Attempted Establishment of a New Purple Martin Colony by Displacement of a Nesting Pair from a Colony 1000 ft. Away

Ken Kostka
American Swallow Conservancy
514 Painter Ave.
Natrona Heights, PA 15065
Sept 1, 2022

Dedicated to the Preservation of the Purple Martin

My colony at left end of red line and my friends’ uncolonized site at right end, 1000 ft. distant

SUMMARY: In an attempt to establish a new Purple Martin colony in my neighborhood, 20 miles northeast of Pittsburgh, PA, I displaced three pairs of gourd-nesting martins from my backyard colony while offering identical gourds on a rack in my friends’ orchard, 1000 ft. to the east. One pair re-nested at the new site and fledged 3 young. This lone nesting pair generated a large amount of martin activity by attracting many visitors. Whether a new colony has been established will be determined by whether multiple pairs breed at the new site in 2023.

Purple Martin colonies in the greater Pittsburgh area still uncommon. While having made a comeback over the past 20 years, there are still relatively few colonies in the four-county area around my home (Allegheny, Armstrong, Butler, and Westmoreland). Since 2021, I ‘ve tried to help my friends who live nearby start a new martin colony. I knew having my active colony less than a quarter mile away would make it easier, but their orchard is somewhat tree-enclosed, so I knew it would be challenging. However, their orchard is also in a nearly direct line between my colony and the “lake-like” Allegheny River, where martins from my colony often forage, so I knew their site would get a lot of exposure to passing martins.

Orchard clearing with gourd rack

No martins were attracted to the gourd rack in 2021. I tried again beginning in late April of 2022, but none were attracted by late May, so I decided to displace several pairs from my own colony, 1000 ft. away. My backyard colony consists of a lone T-14 wooden martin house. I limit the number of Purple Martins in my wooden house to 8-10 nesting pairs because of its proximity to several neighbors. I am happy with a small colony, especially since I manage a large 40 pair colony 2 miles to the north at a local county park. My yard is fairly wide open. My colony is 12 years old and very popular with the martins since I do a lot of supplemental feeding. The house fills up with mainly ASY (2+ year old martins) pairs by late April.

View of gourd rack from the north

The 10 ft. high gourd rack is situated in an orchard 1000 feet away from my colony. This orchard, long and beautiful, gently slopes to a thickly wooded hillside that drops steeply to the Allegheny River 250 ft. below and 1/4 mile away. The gourd rack is in the center of the most open area in this somewhat tree-enclosed orchard. The overhead GoogleEarth photos of the site are 10 years old. Many of the large, tall pines just north of the gourd rack clearing in the GoogleEarth photo are now gone, creating an even larger clearing. The current photo to the left was taken from the the northern end of this clearing where the pines used to be. The clearing is approximately 65 ft. by 150 ft., with 25 ft. tall trees at the perimeter, but much taller 50 ft. trees (including pines) in all directions at a greater distance. There are several open areas nearby. (All ground level photos are current.)

My T-14 martin house

My strategy for starting the orchard colony in 2022 was to allow my T-14 to fill up with the usual 8-10 pairs in April, then hang 5 gourds under my T-14 and wait for new martins to settle into the gourds. Once the gourd-nesting martins had attracted mates and begun nest-building, I would remove the gourds, forcing the martins to seek out a new site. Hopefully one or two pair would choose to re-nest at my friends’ orchard site nearby, and move into an identical gourd in the gourd rack 1000 ft. away. I hoped to improve my chances of attracting a displaced pair to the orchard by employing the “Social Attraction” technique which involves broadcasting martin vocalizations and deploying martin decoys, among other things, in an attempt to convince investigating martins that a site is already colonized.

On May 1st, after all available compartments in my T-14 had filled up, I hung 5 large plastic gourds under my T-14. The martins using these gourds took supplemental feedings during the month of May, just like the ones nesting in the T-14.

By May 28th, three of the five gourds hung under my T-14 had attracted what I believed to be mated pairs, and I saw activity on all 5 gourds. However, only 1 of the gourds had an almost completely built nest, with green leaves being brought in, a sign that eggs would be laid soon. Therefore, I could not wait any longer, and removed all the gourds at noon, displacing all the gourd-nesting martins. This removal of course created confusion, with the displaced martins sitting on the gourd arms, the porches of unused (blocked) T-14 cavities, and the roof of the T-14 throughout the rest of the afternoon and evening. One big advantage of using gourds is that they can be removed entirely, causing the martins to disperse more quickly, I believe, as opposed to blocking a cavity of a martin house.

My backyard colony at 514 Painter Ave.

Although I did not originally plan to replace the gourds on the orchard gourd rack with the gourds which I was removing from my T-14, it made sense to do this since they already contained partially built nests (without any eggs), which the displaced martins might recognize. But the bigger advantage in moving the gourds, which I had not anticipated, was that two of the five gourds I hung under my T-14 were partially spray-painted different colors from a transplant project I had done in 2007. Two of the three pairs occupied these colored gourds. One gourd had it’s front painted gold – the other red. This was lucky – and may have proved pivotal. In retrospect, I wish I had color-coded all 5 gourds. The martins might associate the color with their nest, making them more likely to recognize and continue nesting in their gourds at the new site. Also, they might be more likely to continue nesting if their nest was moved to the new site along with the gourd.

Closeup of gourd rack at orchard site

I immediately took the gourds I had removed from my T-14 and placed them on the gourd rack in my friends’ orchard, 1000 ft. away, replacing 5 of the 6 gourds on that rack, which were of the same exact type (large white plastic gourds with Excluder entrance holes). I tried to orient them in approximately the same compass direction. Only one of the 5 gourds had a finished nest with green leaves – the gold-fronted gourd. The other two gourds which definitely had established pairs before being removed, a red-fronted gourd and an unpainted white gourd, had only trace amounts of nesting material, although the red gourd had a few green leaves.

I also immediately began continuous daytime broadcasting of Purple Martin dawnsong at the orchard site, and rearranged the decoys. In addition, I placed two unused T-14 sections on a chair and attached decoys to the porches. These T-14 sections were too low for nesting, but I hoped they would serve as another visual stimulus to the displaced martins, reminding them of my backyard colony site. They also served as a weatherproof place to store the smartphones which drove the portable bluetooth speakers that broadcast the dawnsong.

What follows is a day-to-day record of martin activity at the orchard site after the displacement. (Visits by other martins are in bold.)

May 29, 2022 In the morning, there are some still displaced martins hanging around my T-14, but it seems most of the displaced martins have dispersed. I believe removing the gourds altogether, rather than just blocking the entrance holes, expedited the dispersal.

1:00 PM My friend Jameson texts me that many martins are flying above the gourd rack!

2:00 PM When I arrive several hours later, I see two Purple Martins swooping around the gourd rack. An ASY-M landed on at least one gourd porch.

5:00 PM I arrive to check the food and water in the House Sparrow bait traps (situated under an apple tree 30 ft west of the gourd rack), thinking no martins are present, when an ASY-M flies off the porch of the gold-fronted, south-facing gourd.

May 30, 2022 88 F hot, sunny

10:15 AM I increased the volume on the portable dawnsong speakers, and a female martin appears on the porch of the gold-fronted gourd. I think she came out of the gourd when I turned the volume up. She did not flush when I approached. Eventually she flies off and an ASY-M came in and landed on the gourd porch. He eventually takes off and they both flew around.

8:26 – 9:00 PM Two martins are buzzing around – flying above the orchard canopy, occasionally dipping down towards the gourds. I hear bluejays and grackles giving loud mobbing calls above a patch of tall pines just north of the site. Soon I see 3 martins, and eventually 5 circling around. A Great Horned Owl (GHO) flies out and lands at the top of a 50 ft.all pine tree about 90 ft. southwest of the gourd rack. The martins join in the mobbing. The owl soon flies off to the south and the martins disappear. I think the displaced martins are roosting in trees because of the hot weather and because they are not yet comfortable roosting in the gourd rack.

View of gourd rack from the south

May 31, 2022

10:00 AM A pair of martins, ASY-M and F (age unknown), are bringing green leaves into the gold-fronted gourd! There is a wren entering all the gourds, so I put up a gourd on a shepherds hook under an apple tree 30 ft west of the gourd rack. The wren eventually nests in this gourd.

3:00 PM I put a better predator guard on the gourd rack pole, as well as bird netting to stop any snakes. I see 2 martins flying above the site.

8:30 – 9:00 PM I did not see any martin activity at the orchard site.

June 1, 2022

8:00 AM an ASY-M is sitting on the inside porch with just his head looking out. Later in the afternoon, I checked for eggs but found none. There was a big storm later in the day.

June 2, 2022 slightly overcast. a bit cool

8:00 AM The pair was inside their (gold-fronted) gourd and eventually exited. I tried supplemental feeding by tossing egg while the female was sitting inside looking out but she did not go after any egg. Eventually, I counted six martins circling above site at about 40 feet. I kept tossing egg and one did eventually go after a piece but veered away at the last second.

11:15 AM Female exits gold-fronted gourd. ASY-M brought green leaf and female snuck back in when I wasn’t looking. As I was leaving, I saw 2-3 martins circling. Owl was being mobbed in the pines to the north.

1:30 P M Male brings green leaf. Female comes out of gourd and snaps up a piece of tossed egg I had intended for the male! Later, I see a non-ASY-M martin sitting at the very top of a 50 ft. pine about 175 ft. south of the gourd rack. Is it the female?

3:30 PM I removed the decoys from the gourd rack and put them on the porches of two T-14 sections that I have sitting on a table by the firepit about 30 ft south of the gourd rack. The portable speakers playing the dawnsong are also placed on these T-14 sections.

5:15 PM Male flying around and went after a piece of tossed egg but veered off. Female sitting inside gourd. I tossed egg to lure her out but she stayed put.

I sat on a chair in the landowners fire pit (which is about 30 ft. south of the gourd rack) and female did not flush. I want her to become accustomed to people sitting in the fire pit area because the landowners occasionally use it for parties and I do not want their presence to scare the martins.

View of my colony, orchard site, and the Allegheny River

8:15 PM cool evening and it was rainy today so I tried tossing egg again and 1 martin took a piece. There were 3 flying around so I’m not sure which one. I suspect the pair will spend the night in the gourd. It definitely seems like martins from my site are visiting more frequently since the pair is here.

June 03, 2022

11:15 AM Female enters gourd as male ushers her in. Several minutes later, I hear the ASY-M emit what I believe to be a vocalization intended to recruit other martins to the site. I call it the “screaming banshee” vocalization, and I soon see 3 other martins following him around at a height of about 100 ft. above the site. He is recruiting! I’m not sure if these 3 other martins are from my colony or not but it is really cool! I see as many as 5 other martins flying very high – about 200 ft. – and he continues the banshee call. There is still time for martins to start nesting or renesting, so I am hopeful that at least one other pair will choose to nest in the gourd rack.

Yesterday, a couple who lives about 1500 ft. north of the site, and been trying to attract martins for several years, said they’ve had martins visit twice in the past week. She says these visits inspired them to get rid of the House Sparrows! I think his was the first time they had seen martins in many years.

June 04, 2022

11:15 AM Female inside gourd looking out, and eventually flew out. No other martins around. I turned the volume up on the dawnsong speakers.

June 05, 2022

11:30 AM The pair is in the gourd. Eventually the male flew out and brought back a green leaf. Two other martins are flying around. One briefly landed on a north-facing gourd porch. When all the martins are away, I lower the rack to check for eggs and found 2 eggs in the gold-fronted gourd!

June 06, 2022

11:30 AM 2 martins cavorting above the site.

June 07, 2022 62 degrees. rain

1:00 PM It has been raining all morning, so I try tossing pea-sized chunks of scrambled egg. The female is looking out of the entrance hole and when I toss the first piece, she emerges and eats 7-8 pieces of tossed egg! Male not present. I also fed a lot of egg at my backyard T-14 colony.

7:00 PM Just before a big rain, I fed the female 4 pieces of egg and fed the male 1 piece. He didn’t seem very hungry. Perhaps he was eating egg back at my colony site!

June 08, 2022

8:00 AM Toss-fed female 4-5 pieces of egg. Male not around.

View of the gourd rack from the west

2:00 PM Male exits gourd. 3 martins flying around. When there are no martins in sight, I lower the gourd rack and find FOUR eggs in the nest of the gold-fronted gourd! [No more eggs were laid, so I’m assuming she is an SY-F (“subadult”, first-year breeder, meaning she was born last season)

June 09, 2022 60’s cloudy and a bit cool.

12:00 PM Male emerged from gourd and ate 2-4 pieces of egg. Then the female showed up and ate a bunch too. They both ate a good bit! The female chased a House Sparrow off the gourd rack quite aggressively. Perhaps it’s been trying to enter her gourd. I reset the House Sparrow wire bait traps.

7:30 PM I toss-fed the female 5-6 pieces of egg and the male 2 pieces. My colony on Painter Ave. (1000 ft away) have been taking tossed egg to their nestlings all day.

June 11, 2022

12:15 PM Pair inside gourd. Female exits; male stays inside. I notice that the tall grass around the firepit area (25-30 ft. to the south of the gourd rack) has been weed-whacked. Erica and Jameson (the property owners) have talked about having a get-together tonight around a fire that night. (The firepit is only 30 ft. from the gourd rack) At first, I was unconcerned, remembering how, when I worked at the Purple Martin Conservation Association, campers would have gatherings around fires at similar distances from the large colony at Indianhead Landing on the shores of Edinboro Lake, without bothering the martins. However, I later realized that that was a large established colony where the martins were accustomed to the activity. Here, this was a lone pair nesting for the first time, and I was worried that the nightime activity could spook the incubating female off her eggs and cause abandonment, and I relayed these concerns to the landowners. But moving the firepit or foregoing the get-together was not to be, so we decided to take a “whatever happens, happens” approach. It would be a learning experience either way. I did suggest they avoid going near the gourd rack at night. I also consulted with Jamie Hill, Founder of the PMCA, and he said that even if the female were scared off the eggs on this warm summer night, so early in incubation, the eggs would not be harmed. I did not attend the get-together but I did walk down very late and briefly observed while the party was still going. It was pretty loud, with guitar music and general revelry – and I have to admit I went to bed a bit worried.

June 12, 2022

My fears were apparently unfounded, as the pair is still present and attending the nest! In retrospect, I’m glad the landowners didn’t cancel or relocate the firepit gathering since I learned the martins will tolerate such activity. Adam Troyer of Conneautville, PA, suggested that the martins may have been accustomed to noise at night since martin roosts in South America are sometimes very noisy. The roost can form in the trees above crowded city streets or in oil refineries. I wonder, also, if all of my supplemental feeding and management activity helped to accustom the martins to general human activity and further bond them to the site, making them more tolerant of this unusual nigh-time activity. I fed the pair of martins on at least four separate occasions several days prior to the party, and was present daily while starting, adjusting, or ending the dawnsong, in addition to trapping House Sparrows nearby.

June 13, 2022

I finally caught the House Sparrows that were snooping around the gourd rack and attempting to nest in an unused gourd.

June 21, 2022

12:30 PM The male exits. After I’m sure neither parent is present, I lower the gourd rack and find that 1 egg has hatched!

3 day old nestlings inside gold-fronted gourd

June 22, 2022

12:30 PM I do a nest check and find 3 hatchlings!

6:00 PM I do another nest check after a big windstorm and the nestlings are fine. I reorient or substitute several unused gourds so that they all face a more open direction (see diagram)

June 23, 2022

12:15 PM Another ASY-M is snooping around the gourd rack!

8:30 PM As it is starting to get dark, I count 6 martins flying in the sky above the area of the gourd rack. I realize an owl is nearby and it eventually flies off in a northerly direction. I see or hear owls quite often in this orchard. There are quite a few tall pine trees just north of the site and I suspect there must be an owl nest nearby. I have noticed on several occasions that when the male exits the gourd, he flies UNDER the apple tree 70 ft. to the south. There is about 6 ft. of clearance under the tree and it must be easier to exit the area of the gourd rack by doing this rather than climbing steeply.

June 24, 2022

12:30 PM Found 1 mite on a nestling. Saw a House Sparrow snooping around, so I set the bait traps again but did not catch it.

June 25, 2022

12:45 PM All 3 nestlings look very healthy. I saw 4 martins flying around. I reset the sparrow bait traps.

June 26, 2022

12:20 PM Both parents inside gourd. When they exit, I did a nest check. All 3 nestlings look very healthy. I removed the old, unhatched egg. It was infertile.

June 27, 2022

12:00 PM All 3 five day old nestlings look very fat and happy, There are 4 martins flying around.

My friend Jameson and his kids with the 15 day old nestlings born at their orchard site.

June 28, 2022

12:30 PM I saw a pair of Cliff Swallows (I think) flying above the site.

June 29, 2022

6:00 PM Nest check – all good.

July 02, 2022

12:30 PM The 3 ten day old nestlings are doing well. Saw 4 martins at the site – male was giving alarm call.

July 04, 2022

12:00 PM All 3 young, now 12 days old, are doing well. Interestingly, there has been a LOT of activity at my backyard colony site, 1000 ft. away- way more than usual. I had 2 very late nests at my colony – much later than ever in the past 12 years. (I saw martins as late as Aug. 31st!, While one of these very late nesting pairs was a renest, I believe one of these pairs may very well have been displaced martins that re-nested in a T-14 compartment after being displaced from their gourd. (I reopened several unused T-14 cavities sometime on or after June 22 that had been closed on May 28th, the displacement day.)

July 06, 2022

2:00 PM Saw 4-5 martins flying above and around gourd rack. I notice how the parents circle above the orchard canopy and swoop down steeply when coming in to feed nestlings. When leaving, they seem to have zero problems climbing steeply to clear the apple tree 50 ft south of the gourd rack. Sometimes, they fly under the apple tree, which has about 6 ft. of clearance.

7:30 PM Again, I see 4-5 martins flying in the area of the gourd rack.

July 07, 2022

3:00 PM Nestlings are 15 days old and look very healthy. I did a nest replacement to rid the gourd of any nest parasites. This just means removing the old, sometimes parasite-infested nest material and replacing it with 2-3 inches of chopped straw or soft white pine needles.

July 09, 2022

12:30 PM the 3 nestlings are fat and happy. They scolded me when I removed them to take a photo. There are 4 martins flying around.

July 13, 2022

5:30 PM The 3 nestlings look good.

8:30 PM An owl (GHO) in the pines flies off when I approach, as I count 6 martins flying around. Back at my colony, I counted 20-25 martins come in for the night. (This includes fledged young. Six nests have fledged.)

July 15, 2022

2:00 PM I decided to try tossing 5-6 giant mealworms to the ASY-M. He caught some but did not take any into the gourd.

July 18, 2022

1:00 PM 6 martins flying around. 3-4 ate some tossed giant mealworms. It is raining lightly.

July 20, 2022

1:30 PM 5-6 martin flying around. The nestlings are 28 days old today (the day they normally fledge) but I don’t want to cause premature fledging. The ASY-M parent scolds me when I go near the gourd rack. I tried tossing mealworms but no martins were interested.

8:00 PM 6-7 martins flying around.

8:30 PM 8 martins flying around the orchard area in a group.

July 24, 2022

2:00 PM ZERO martins present during nestcheck.

8:30-8:45 PM Only 1 martin (non-ASY-M) calling and circling.

Aside from the evening of the 24th, I did not have the opportunity to be at the gourd rack in the evenings when the fledged martins (and parents) would have been due to come in for the evening.

In late July or early August, I did find one dead juvenile martin in an unused gourd. I assume it was a fledgling from the gold-fronted gourd.

DISCUSSION: While I cannot definitively prove that the pair I displaced from my colony was the same pair that nested in the orchard gourd rack (since they were not banded) there is overwhelming anecdotal evidence to suggest they were the same pair. First, the pair appeared at the orchard site the day after I displaced multiple pairs from my colony. Second, the male was ASY, just like the male that was displaced from my colony. Third, they used the same color-coded, gold-fronted gourd that was removed from my colony. Fourth, they seemed rather tame, and took multiple supplemental feedings just like the pair that was displaced from my colony.

SUMMARY: On May 28th, I displaced 3 pairs of gourd-nesting martins from my colony and placed their gourds on a gourd rack in my friend’s orchard, 1000 ft. away. The next day, many martins were seen investigating the orchard site, and one pair moved into their transplanted gourd at the new site. By June 7th, they had laid 4 eggs in their gourd and on June 22, they had hatched 3 nestlings. The 3 nestlings fledged sometime between July 21 and July 24.

Of course I will not know until 2023 if I was successful in establishing a new colony, since one pair is not a colony. But several facts make me optimistic. First, there were multiple visits by other martins over the course of the 2 month period during the successful nesting of this lone pair. On at least 20 occasions, anywhere from 1-7 additional martins (usually 2-3) were seen flying around the area above the gourd rack. These may have been martins from my colony, the colony 1 mile north, other colonies, or non-breeding floaters. They may have been nesting or non-nesting martins. and since I was only present at the orchard site a fraction of the time, I think it is reasonable to assume that there were many other martins that visited the site when I was not present. One breeding pair attracts a lot of interest from other martins!

View of gourd rack from the east

I believe attracting a lot of visitors is key for a lone pair to establish a colony the following year. When I established the colony in my backyard in 2011, the lone pair had many visitors, and in 2012, there were 12 breeding pair! Similarly, in 2005, when a lone pair nested at the USACE Lock 4 colony in Natrona, PA, after being displaced from their T-14 wooden martin house at Saxon Golf Course near Saxonburg, PA, many martins visited the site, even though the closest colony was 8 miles away!. Here is an excerpt from that article: “Perhaps most amazing is the fact that a total of AT LEAST 17 additional martins visited the Lock 4 breeding site on at least one occasion between June 17th and August 28th, demonstrating that one breeding pair of martins acts as a magnet in attracting other martins. Many of these martins were frequent visitors to the site. It will be interesting to see if any breed there next season.” 6 pair bred at the Lock 4 site in 2006! (3 successfully and 3 unsuccessfully). In fact, the original banded male was not one of the martins that returned in 2006, and yet six pairs attempted to nest!

The martin pair at the new site accepted supplemental feedings on multiple occasions. Could this supplemental feeding have contributed to their breeding success? Could the fact that they became accustomed to these feedings make them more likely to return to the new site in the following year?

Factors that may have contributed to the pair accepting the new location of their gourd:

Close-up of
gold-fronted gourd

Advanced nest. Of the three pairs displaced, the only pair that stayed with their transplanted gourd and nested at the nearby site was the pair with an advanced nest that was ready to receive eggs. The other 2 pairs had scant nests in the early stages of construction. Perhaps the advanced nest was a sign of a strengthened pair-bond which increased their chances of staying together and staying with the nest.

Color-coded gourd. Also noteworthy is the fact that their gourd was color-coded. The front was spray painted gold. This may have been key in allowing them to recognize their gourd in its new location. Might they have moved into a non-color coded white gourd if their gourd wasn’t available. Yes, but I think the color-coding was a big factor.

Adult male. The fact that the male was ASY may also have been significant. Adult males are more attractive to females, and he may have been more effective than a subadult male in convincing the female to stay with the transplanted gourd.

I do not plan to hang any gourds at either of the two nearby colony sites in 2023. Hopefully this will insure that the returning pair and any visitors or displaced gourd-nesting martins in 2022 will nest at the new site.

One possible disadvantage of the orchard site is the stark presence of Great Horned Owls. Owls were spotted on multiple occasions, so much so that it is possible they may have been nesting in one of the nearby tall pines. Martins participated in mobbing the owls on 2 or 3 occasions.

A few words about the “social attraction” element of the project: I feel that one important factor in getting the displaced martins to accept the orchard site may have been that it was open and available to them even when they began nesting in my backyard colony, allowing them to become familiar with it. Not only did they encounter the site when flying towards the river to forage, but I played the same dawnsong vocalizations at both sites and deployed decoys at the site. I probably should have put some decoys on my active T-14 as well! My point – they may not have adopted the orchard site if the gourd rack was not put up until after the displacement.

PLEASE NOTE:: Trapping, banding, and transport of Purple Martins or their eggs requires state and federal wildlife permits.

POST SCRIPTS: Adam Troyer suggested raising the gourd rack from its current 10 ft. height to make it more attractive to other martins next season, considering the somewhat tree-enclosed nature of the orchard. I gave this a lot of thought and feel it is an excellent idea. Therefore, I am adding 6 feet to the rack. The gold-fronted gourd will sit at a height of 16 ft. in 2023, rather than 10 ft. At first, I thought the drastic increase in height might put off the returning pair (assuming they both return), but I felt it would not, and that it was important to make the site more appealing to other martins investigating the site in 2023. I will also continue to use the social attraction technique in 2023. I think a significant portion of the overflow from my backyard colony will go to the orchard site in 2023, considering it was an active site in 2022. In December of 2022, seven additional large dead pine snags were cut down from the area just north of the gourd rack! This removal has created an even larger open area north of the rack. In fact, there is now a 120 ft. long by 60 ft. wide “corridor” just north of the rack, and the land owner plans to remove even more!

ABOUT THE AUTHOR: Ken Kostka has been involved with Purple Martins since 1981 when he built a martin house in 10th grade woodshop. He was a writer and research assistant for the Purple Martin Conservation Association from 1999-2003, where he played a key role in developing an emergency feeding technique that has saved 1000’s of martins from starvation during martin-killing weather in Pennsylvania and nationwide. In addition to his backyard colony, he manages three other colonies in the Pittsburgh area, a 20 pair colony at Saxon Golf Course near Saxonburg, PA, a 30 pair colony at Crooked Creek Park near Ford City, and a 40 pair colony at Harrison Hills County Park in Natrona Heights, PA, about 1 mile north of his home. He established 3 of these colonies and has managed them for many years. The orchard site is also adjacent to the property where he grew up and tried to establish a martin colony for 27 years, without success, making him especially motivated to make this project succeed!

2020 Purple Martin Journal

The photo above is my original martin house erected in 1979
2020 Purple Martin Journal
Ken Kostka
American Swallow Conservancy

This is my journal for the 4 colonies I manage in southwestern PA. Abbreviations: WH=compartment in wooden house or porch. All my housing is T-14’s, some with gourds hanging from them. I have underlined entries of note, and plan to publish an article about the 2020 cold weather, martin-killing event at a later date. I fed well over 500 eggs to the martins at my 4 colonies between April 10th and May 12th, 2020. While the number of martins grew, as the journal entries indicate, I estimated the amount of egg consumed at an average of 1/3 egg per martin per feeding.

514 = 514 Painter Ave., Natrona Hts., PA. This is my backyard, home colony. It consists of a T-14 with only 9 compartments open. I had 8 breeding pairs in 2019
HH = Harrison Hills County Park colony at ELC (Environmental Learning Center) in Natrona Hts., PA, is 1.8 mi. north of 514 and had 35 breeding pairs in 2019
SGC = Saxon Golf Course colony, 1 mi. south of Saxonburg, PA, is 7 miles northwest of 514 and had 22 breeding pairs in 2019
CC = Crooked Creek State Park colony in Ford City, PA is 12 miles north east of 514; had 2 pairs in 2019 (new colony)

March 25 514 ASY-M swoops around vocalizing loudly at 514 !!!! earliest ever by a week! (I think)

Mar 26  514 I did not see ASY-M in AM.
9:45 AM a friend, Daniel Kisiel, who visits HH frequently, messages me that he has seen a martin at the Harrison Hills County Park colony (along with 2 Barn Swallows).
7:18 PM ASY-F on WH-14 at 514

Mar 27 514 8:00 AM ASY-M and F on WH-11 and WH-12 (porches)

Mar 28 514 still one pair at 11 AM. But at 5:30 PM there were 2 ASY-M and a female

Mar 29 74 sunny windy. 514 2 ASY-M in AM. 3 martins in afternoon. 4 martins at 6:00 PM

Mar 30 514: 6 martins at 11 AM. (2 females) All ate 2-3 pieces of egg. 5:15 PM 7 martins – had to roust out to feed. Har. Hill: Daniel Kisiel reports a martin flying VERY CLOSE to him “as if it were saying hello”. I told him it wanted fed!

Mar 31 45 degrees. cloudy, damp. 514: 7 martins (5 male, 2 female) ate intermittently all day. I chased pair out of WH-8 to feed.
Harr. Hill: 1:00 PM 3 martins. I think all ate some egg, but not as much as I thought they would. Met Daniel and showed him how we feed.
Crooked Creek 3:00PM NO MARTINS PRESENT!
Saxon Golf Course 5:00 PM NO MARTINS PRESENT! Checked wooden pole and it seems very solid.

Apr 05 62 sunny. 514 Eight martins!

Apr 06 65 sunny. 514 Eight martins; Harr Hills: 12-14 martins (per Dan Kisiel)

Apr 07 65 sunny, rainy. 514 12:30 PM – 10-11 martins; 6:00 PM – 12 martins. Fed (tossed) egg on and off all day.

Apr 10 hi 44 windy cold 1″ snow overnight! 514: 17-18 martins! ; Harr Hills: 25-30 martins;
Saxon GC: 8 martins; Toss and tray fed at all 3 sites.

Apr 14 hi 44 cold. 514: 19 martins (8 female and 11 male) ; Harr Hills: 25-30? martins; Saxon GC: 5 martins (there were 8 4 days ago so several must have just been passing thru); Toss and tray fed at all 3 sites. Crooked Creek: 3:00PM ZERO martins present. It is supposed to be hi 40’s for the next three days!

Apr 15 hi 49 sunny but chilly and somewhat windy.

Apr 16 hi 45 cold. 514: 21 martins! ; Harr Hills: about 25-30? martins;

Apr 17 hi 43 cold snow rain. 514: 21 martins at 1:00 PM but 23 martins at 6:40 PM !!! (13 of these 23 were female) Harr Hills: 25-30? martins; Saxon GC: 11 martins at 12:30pm!!! So during this 4 day cold, martin-killing weather event, Saxon GC went from 5 to 11 martins !!!

Apr 18 hi 40’s still chilly. 514: 30 martins at 9:00 AM !!! Where are these extra martins coming from? Harr Hill? Surely these martins are not migrating in this chilly, 40-degreeish weather! There were 23 again at 11:00 AM. This number includes 6-7 martins found communal cavity roosting in WH-14! I flushed them out before feeding. Harr Hills: 25-30 martins but it seems more showed up when I was feeding…could they have moved from 514 Painter, less than 2 miles south???
It is at this point (30 martins at 514) that I decided to focus my supp/emerg feeding efforts at HH, since I was getting so many martins at 514. I assumed that since I was feeding most often and heavy at 514, martins were coming from HH to seek out food, and I grew worried that 514 was becoming a feeding station – WHICH I DO NOT WANT !!!! (because my neighors have complained about droppings in the past) I’m OK with HH being a feeding station. It would only take a martin about 3 minutes to fly from HH to 514. (at 32mph). So I started feeding at HH FIRST in the AM, and always made sure there was food on the trays THERE before putting any food on trays at 514. In fact, I no longer tray feed at 514, or rarely….and ONLY if there is food on HH trays. This strategy seemed to work as I am not getting more than usual number of martins at 514 and there are TONS at HH.

Apr 19 hi 57 mostly cloudy wind 10-20 514: did not feed in the AM (all martins were out by the time I returned from Harr. Hills) but found 2 dead martins in WH-14, one male and one female, each weighing 33 grams. 2 dead martins despite me feeding at this site at least twice a day for the last 5 days!!! ??? These must have been untrained martins that arrived underweight and were just passing thru??? Martins began returning for the evening at 6:15 PM and ate quite a bit. There were 13-14 martins that started landing on the house at 8:00 PM, so 7-10 of the 23 martins (2 of which died) were either passing thru or visiting from other sites. Harr Hills: ~30 martins ate quite a bit around 10:30 AM. Found a dead ASY-F stuck in a door which weighed 60 grams!! Toss-fed again around 7:00 PM and the martins ate quite a bit!

Apr 20 hi 57 sunny. Martins ate heartily at both HH and 514 in AM. Also ate heartily in PM at 514 (I did not visit HH in PM)

Apr 21 hi 48 cloudy. some sun. winds 20 mph. occasional lite snow!!! Martins ate heartily several times in AM and early afternoon at both HH and 514. 40+ martins at HH. 14-16 at 514. When I returned to 514 from big feeding session at HH, there were only 2 martins at 514 at 12:15 PM. Could some have gone to HH to feed?? When I checked comps at 514 at 2:15PM, there were about 5 martins already hunkered down inside comps (different comps), so I flushed them and re-fed (toss-fed), but will not disturb them again today. HH is exactly 1.8 mi. north of 514 and I am convinced the HH birds were visiting 514 to feed, so I have made it a point to make HH the primary feeding place, because I do not want to get a lot of “feeding visitors” at 514 (neighbors have complained about dropping in the past). So I cannot afford to have 514 become a big feeding station! But HH would be OK. Fed heavily again at 5-6 PM at both HH and 514. Found dead ASY-M stuck in door at HH. Weighed 52 grams. Second stuck martin at HH during this cold spell tells me there a possibly a significant number of martins “passing thru” that are not familiar with excluder entrance hole.
It occurred to me that it was a good thing that Lock 4 housing never got opened since I would have been unable to go there with the Covid-19 restrictions. These birds are surely hunkering down at HH or 514, where I am feeding heavily. I hope that any early returners from Crooked Creek are at HH, where they will learn to take egg. I think it possible that early returners to smaller, newer colonies might hang out at larger, older colonies during cold snaps anyways….perhaps to get into communal cavity roosts?….but can learn to take supp. feedings there! Perhaps even early arriving ASY-Y’s from older but smaller colonies might gravitate towards large colonies for this reason – and to feed where they know supp feeding may be occurring.
Why not keep smaller, newer colonies closed early so early returners from those colonies are forced to congregate at one large, centrally located colony where they can be fed more efficiently in case of a cold snap. I wonder if any ASY’s will return to Lock 4 if I am able to reopen by early May?

Apr 22 hi 48 (36 in the AM) sunny breezy. Martins were very hungry in AM, very hungry in afternoon, and moderately hungry in evening. Fed tossed egg at HH & 514 all day, and Saxon GC at 1PM. There were 7 martins at Saxon at 1:00PM. 15 martins at 514, and 40 or so at HH. I think some of the martins at 514 went back into their comps after the morning feeding, because I counted 5-6 (in different comps) about an hour after feeding (I did not flush them because it was very cold), but all comps were empty by 4PM when it started getting towards 50 degrees. I found another dead female at 514 in WH-14. She weighed 36 grams

Apr 23 hi 63 (47 at 11 AM) sunny. rain after 3pm. Fed at HH and 514 in AM around 11am. Martins ate a decent amount – not nearly as hungry as yesterday.

Apr 24 hi 63 (49 at 11 AM) sunny. toss-fed at HH and 514. Martins ate heavy in AM. 40-50 at HH and 16 at 514.

Apr 25 Nice, sunny! no feeding

Apr 26 hi 49 softly rained all day! Toss fed at HH in AM and afternoon. put lots of egg on trays after afternoon toss-feeding and did not return. ALL egg was gone the next day. One advantage of rain is that it keep the egg soft !!! It helps to soak the tray egg on sunny days to keep it moist and more palatable to the martins.

Apr 27 hi 57 (44 degrees at 10-11 AM) became part sunny. Toss fed at HH and 514. 50? martins at HH? (Lots!) 16 martins at 514 (didn’t look inside)
Drove by Lock 4 yesterday. Tarps still on houses. Turns out this was a good thing. Getting access to this facility is a pain and it’s just as well the martins were forced to disperse to either HH or 514. I will email lockmaster soon to ask permission to permanently remove houses. No longer have to deal with Springhill, trains, or gates.

Apr 28 hi 68 1/3 sunny and 2/3 cloudy (49 at 10:30am) HH: MANY birds…50? Fed heavy in AM. 514 – 16 martins also toss fed pretty heavy. Toss fed heavy again at 7-8pm – both sites.

April 30 hi 53 Cloudy and cool all day. fed heavy at both HH and 514.
May 01 hi 54 Cloudy and cool all day. fed heavy at both HH and 514.

May 04 hi 53 Fed at HH and 514 (More tray-feeding at HH because of so many martins.) They all seem to get a few pieces because when I come back shortly after tray-feeding, they don’t swarm me – they just sit on the houses – porches are PACKED !!!

May 05 hi 56, but cool in AM. 16 martins at 514; they did not feed in the PM like the martins at Saxon GC. Van thermostat said 57 at 6PM. Fed at HH, 514, and Saxon GC, where there were 21 martins! Tore out 6 House Sparrow nests, most of which had eggs. I loaded they trays after feeding heavy, knowing it would rain all day tomorrow, and the martins would have one decent meal at least. Visited Crooked Creek around 5 PM and saw martin sign! Lots of droppings and definite activity in WH-15 and WH-16. Loaded two trays with egg, just in case the martins there are egg-trained. I did not see any martins but it was 55/56 degrees and they were probably out feeding. Could they be coming to HH to feed??? Could the Saxon martins be visiting HH to feed?

May 06 hi 44. 16 martins at 514. Lots of rain. cold. Fed heavy at 514 and HH. Only toss-feeding at 514 because starlings get into trays. Tray fed twice at HH and toss-fed once (partial)

May 08 hi 49 fed at HH and 514. cool. martins very hungry. martins ate off brick pile where I had placed some egg (at 3 ft. off ground) for bluebirds, cardinals, etc,,,) even though 514 martins fed well (toss)

May 09 hi 43. Cold. windy! brutal! some snow squalls. some sun later (43 degrees at 6:00pm). wore tassel cap and scarf! in AM and early afternoon. 514: toss fed all day HH: Tray fed 3 times and toss fed (thoroughly) once. loaded trays at 4pm after the toss feeding. Saxon: 20 martins. windy, many martins seem weak as they exit (had to roust some) but most feed well in high wind. found one dead ASY-F weighed 35 grams. Coopers hawk got one as they were feeding! (ASY-M I think). I tried to rescue but it flew off with it. Loaded 3 trays before I left. Crooked Creek: winds calmed and sun out at 6:15pm when I rousted 7-8 martins from mostly house #2 . One went after spoon-tossed EGG and after an hour, at least 4 others (maybe all) went after and ate as well! I HAD NEVER DONE ANY SUPP OR EMERGENCY FEEDING AT THIS SITE !!!! Some martins seemed weak and wing-drooped, some somewhat clumsy. Two landed on feeder/ pole gourd rack top perch very close to me as I loaded trays with egg. One landed on ground to go after a piece off egg it had dropped. But I was elated – almost cried – when several started going after and eating egg. I really think almost all ate some egg. I loaded 4 trays with egg and am confident some will eat in the AM, if not before dark! This emergency feeding session MAY have saved this colony! Raven was flying over and croaking loudly for quite a while!!?? not sure why – perhaps it was alarmed by me. saw a barn swallow.

May 10 hi 60 sunny breezy cool. saw juvenile bluebird on porch! they have fledged! tray fed in AM and PM at HH. all eaten both times. wing to wing on feeder trays at 7PM. Toss fed in AM and PM at 514

May 11 hi 43. cloudy. HH: toss-fed 2 times and tray fed 2 times; 514: toss fed all day. Saxon GC: toss-fed two times and left food on trays (most was eaten – just crumbs left. ) Crooked Creek: 5:30PM arrived with egg and ALL SEVEN MARTINS ate tossed egg right away! (5 males and 2 females). stayed for an our and toss fed several times. Loaded 4 trays with egg also.

May 12 hi 53. fairly sunny but stiff breeze all day long. 514: martins never left to try feeding. Tossed egg all day to hungry martins. HH: tray fed at 10AM and 5PM Toss fed thoroughly at 6PM. SaxonGC: toss fed at 7pm – had to roust (by lowering houses) about half of the 25 martins present. All ate. Lock 4: removed both covered/unopened martin houses around noon with Scott Allen and helped him set one up at Aspinwall Vets hospital. Scott says he only has 15 of the 45-50 martins present at the beginning of the cold snap. I told him they probably died b/c he didn’t feed enough. All martins hungry today. This was a 3rd day of non-feeding, martin-killing weather. I was a little sad to have to remove the martin housing from Lock 4, since I’ve had housing there since 1999, and a colony since 2005, but it has become impossible to manage the site with Coronavirus restrictions, and even before that, it had become very difficult to conveniently access the site, so I felt it was time to call it quits. I’m hoping this does not affect their choice to roost here. I don’t think it will.

May 13 hi 60 sunny. winds 3-7 mph. Didn’t feed except to a couple at 514 that were still hanging around about 10:30AM

May 14 hi 68 cloudy. no wind. 51 degrees at 10:30AM. I arrive at 1030am at HH and there are no martins present! (maybe 1 or 2) very unusual. So I loaded the trays and left, but came back 5 minutes later (I had forgotten to check the entrance holes for stuck birds) to find a big swarm of martins that did start landing on trays to feed. They must have been out chasing a Coopers Hawk? I toss fed martins at 514 after this.

May 15 hi 78 sunny. saw Tree Swallow

May 19 hi 64. cloudy, windy. martins couldn’t have found much food today. Didn’t feed at any sites

May 20 hi 65. 54 degrees at 10:30AM. chilly and windy in AM. Tray fed 15 eggs to martins at HH and martins were landing immediately. Did not toss feed at 514 because there seemed like more birds than usual and I did not want to draw more in. In marginal weather, unless already stressed, they are better off foraging afar and searching out hard to find food and feeding spots (wind shadows, over water, etc…) They have no young or eggs in the nest yet. When I came back to HH in the afternoon, I discovered they had eaten about 1/2 of the 15 scrambled egg on the trays.

May 21 hi 70. nice sunny day. not windy.

May 22 hi 68. cloudy and light rain in early AM.  Much nice later. sunny after 5PM. not windy. martins not

May 21 hi 70. nice sunny day.

May 24 hi 77. nice sunny day. 514: did nest check and found lots of green leaves but no eggs. lots of mud in WH-2 and WH-3. Wonder where they’re getting it. must do an article about height of housing. My T-14 is only at 9 feet high (lower comps) Upper comps at 11 feet. Don’t need to be high and less susceptible to wind damage. HH: found 1 egg in uppermost compartment of relocated T-14. (WH-35)

May 25 hi 88. hot! 514: saw martins gathering nest material at the end of Boehm’s driveway across the street. Picking up silver maple helicopter seed pods probably.

May 26 hi 88. Hot again! 514: Nest check – all 9 nests have green leaves and WH-7 has two eggs. SGC: Quite a lot of activity for 1:30 in the afternoon on a hot day as martins are usually out feeding by now. This activity is probably the result of newly arriving martins. Did a nestcheck nd found about 15 martin nests, many with green leaves but zero eggs. Removed 9 House Sparrow nests with full clutches of eggs. I wanted to get this done before any martins had eggs, because House Sparrows can destroy martin eggs if their nests are removed. (House Sparrows are a non-native, invasive species that is harmful to native cavity nesters. They are abundant and aggressive and it is legal to remove their nests. They are not a protected species. Be sure to properly identify its nests before removing as you do not want to accidentally remove a martin nest.) HH; stopped by briefly around 2:30 PM and noticed a LOT of activity, due again to newly arriving martins no doubt.

May 27 hi 84. Sunny. no rain. low wind. really nice tropical day! I finished upgrading HHElecFenceTrenchthe electric fence snake guards at the Harrison Hills colony. I had to retrench the underground wire to the relocated T-14. Also changed the steel wire part of the snake guard on all 3 houses to aluminum wire, which won’t rust and conducts current better. (This colony consists of two T-14’s and one T-10, all with gourds.) At the other end of the trench in the photo is the solar charger, which also powers electric fencing for the other two martin houses. I also have a climbing animal guard on all three houses, as well as bird netting bunched up above the guard in case a snake gets over the electric fence. The yellow spacers are key – they keep the aluminum wire from touching the pole and grounding it out. I will do an article about this soon. I put the interpretive poster up also.

May 28 warm, sunny day. 514: Partial nest check at 6PM reveals 2 eggs in WH-3 and 2 eggs in WH-9. several females (WH-4 and WH-7) were on nest and I did not flush them.. I pulled WH-3 nest tray out and female flew. I thought it was a bit odd to have HHcolony2this many females on incomplete nests at 6PM on a sunny day. Also, at HH, I discovered something had pulled up the sod chunks from the trench I dug to lay the electric fence wire. Greg said it was probably skunks looking for grubs. I replaced them and packed them down with a sledgehammer. I took a photo of the colony site.

May 29. rain and wind. high 68. Had Song Sparrows, Carolina Wrens, and adult & 4 juvenile bluebirds eating out of my mealworm feeder at 514

May 31. Crooked Creek 3:00 PM : last visited 20 days ago. Quite a bit of nesting activity. At least 3 nests with eggs and 3 more with green leaves. Found a martin nest CrookedCreek2020with 1 martin egg and 1 starling egg. Tossed the starling egg. CrookedCreekShaleinsideCompThe compartment right above or below had 2 starling eggs in what looked like a martin nest (no starling nesting material). Tossed these. These were WH-8, 9, or 10. This house has wooden crescents and had the 2 martin nests last year. (Didn’t have any starling problems last season.) In house #2, I found CrookedCreekShaleonPorchsmall shale rock pieces on the porch of one compartment (see photo), and the same size shale rock pieces just inside the entrance of a comp. on the opposite side of the house. Saxon Golf Course: removed about 6 House Sparrow nests, most without eggs. It has only been 5 days since I removed 9 nests, so I’ve apparently discouraged at least 2-3 pairs of House Sparrows.

June 2  514: nest check at 3:30 PM. WH-1 had 2 eggs, WH-3 had female on nest, WH-4 had 6 eggs, WH-5 had 2 eggs. (I accidentally scared the pair out – female was still inside when I reached in and I bumped her with my hand.) WH-6 had 3 eggs, WH-7 had 5 eggs, WH-8 had 5 eggs, WH-9 had 5 eggs, WH-10 had 4 eggs

June 7  514 nest check:

WH-1  3E  (3eggs)
WH-2  closed
WH-3  ?  female on nest
WH-4  6E
WH-5  6E
WH-6  3E? (female on nest)
WH-7  5E?  (female on nest)
WH-8  5E
WH-9  5E
WH-10  6E

June 16  514 nest check: 2PM

WH-1  4E (don’t look great)
WH-2  closed
WH-3  eggs – female on nest
WH-4  6E
WH-5  6E
WH-6  6E
WH-7  4Y 4 do (4 young, 4 days old)
WH-8  6E
WH-9  5Y 1 do
WH-10  6E

June 21  514 nest check:

WH-1  8E
WH-2 closed
WH-3  6Y 4 do
WH-4  4Y 4 do
WH-5  2E 4Y 1 do
WH-6  6Y HD (hatching day)
WH-7  4Y 9 do NR (Nest Replaced) a fair amount of blowfly larvea present
WH-8  5Y 3 do
WH-9  4 Y 4 do 1DYD (1 dead young discarded)
WH-10  1E 5Y 1 do

Harrison Hills Nest check at 4:00 PM revealed a total of 49 nests. This is a  98% occupancy rate since there are only 50 available nesting cavities!!  34 nests have nestlings and 15 nests have eggs! Average age of nestlings is about 3 days old. 

June 28  514 nest check:

WH-1  8E
WH-2 closed
WH-3  6Y 11 do NR
WH-4  4Y 11 do NR (1 fell approx. 8 ft. into grass – looked OK)
WH-5  5Y 8 do
WH-6  6Y 7 do
WH-7  4Y 16 do
WH-8  5Y 10 do NR lots of small shells; quite a few blowfly
WH-9  4 Y 11do NR
WH-10  4Y 8 do 1 DYD NR  lots of fleas

Did a bunch of nest replacements at Harrison Hills colony site

Visited Crooked Creek colony site and was pleased to discover at least 17 nests! This has been a breakout year – THE breakout year – after attempting to establish a colony since 1999 ! 12 of the nests had nestlings and 5 had eggs. There were also 4 nests with green leaves, so there could end up being as many as 21 nests ! In one of the nests, I discovered a blue egg. I’m not sure if a bluebird accidentally laid an egg in this nest or if this is actually a blue martin egg ! I took this photo.  The  was in a an Excluder Gourd.  [Postscript: When I cleaned out this gourd on Sept 1, I examined the unhatched eggs by gently breaking them open to see if they were fertile, and they were! All had partially developed embryos (dead of course) except for the blue egg, which I now believe was a bluebird egg. I hypothesize that an aggressive pair of bluebirds took over the gourd after the martins had begun incubating and laid one egg, then abandoned the gourd for some reason. Or perhaps the martin pair failed (i.e., the female died for some reason)  and the bluebirds took over. Impossible to say what happened for sure.]bluemartinegg

I added a ton of crushed eggshell to the trays. There was a nest of green leaves built behind a mirror. This was WH-7. There was also a nest of 5 eggs behind a mirror.


Took a photo of one of the T-14’s during a nest check. I use a ladder to avoid having to remove the predator guard every time I lower the house.


June 30  514 nest check:

WH-1  8E
WH-2 closed
WH-3  6Y 13 do NR
WH-4  4Y 13 do NR
WH-5  5Y 10 do NR
WH-6  6Y 9 do  NR
WH-7  4Y 18 do
WH-8  5Y 12 do NR
WH-9  4 Y 13do NR
WH-10  4Y 10 do NR

Did a bunch of nest replacements at Saxon Golf Course and Harrison Hills. Found almost no nest parasites, especially at Saxon Golf Course! It has been very hot and dry for the past couple weeks, and I believe that’s why – an advantage of the hot dry weather!

July 5  Checked WH-1 at 514 and found 4 young that just hatched today. Also replaced a nestling that had fallen from WH-3. (I was only able to determine this by my nest check records. It looked pretty good…maybe a bit of a runt.)

Did a bunch of nest replacements at Harrison Hills and Crooked Creek colony sites.

July 6  11:30 PM  514: I forgot to look for fallouts with a flashlight when I came home from work at 9:30 PM, and as I walk out to check, a small raccoon has one in his mouth. I began to chase it and yell, and it dropped the nestling just before running into some shrubs, but the nestling was mortally injured and died in my hand. It was no doubt the same one that was on the ground last night.  Damn! I did check for fallouts when I came home for lunch, and there were no fallouts, so it must have fallen out (or been pushed out) sometime between 7 and dark (9ish). I remind myself that Purple Martins are wild creatures, not pets, and it would not be appropriate to get too emotional. We must always do what is best for the martins, and not ourselves.

July 7  The very hot dry weather continues, Did some nest replacements at Saxon Golf Course and, again, found no nest parasites! Nests very clean and the young look great. I did remove SIX MORE House Sparrow nests, 5 of which had partial clutches of eggs!  They never give up!

Sat down and counted up total numbers of nesting pairs at each colony. This only includes nests with nestlings. There are still a handful of nests with eggs so the count could go up, but I am pretty much done doing nest replacements for the season.

514 Painter:                    9 pairs
Harrison Hills Park:    47 pairs
Saxon Golf Course:      16 pairs
Crooked Creek Lake:   14 pairs

It has been so hot and dry that nest parasitism seems very low, so I decided not to do nest replacements on the gourds at Harrison Hills (since its such a pain with gourds), but will keep an eye out for mites. In fact, when I visit Harrison Hills site, I now check for 4 things (with binoc’s): nest mites on gourds, signs of owl predation like broken entrance plates or owl feathers, operation of the solar charger and electric fence, and presence of stuck martins or fallouts. A blade of grass is best for testing operation of electric fence. You feel a tingle when you touch the fence with it – and its not as painful as touching it directly!

514 Painter: around 7:00 PM this evening, I counted AT LEAST 22 martins sitting on the overhead wires on Lincoln St. Since I only have 9 nesting pairs, and no nestlings have fledged, I should only have 18 adults, so there were at least 5 extra, probably more. These extras are non-breeding “floaters” – most likely subadult males that could not get a mate (there’s always a surplus of males in the martin population) or adults whose breeding attempt failed. (It is too late to renest.)   Lots of activity.

July 12  514 nest check: (all nestlings counts approximate)

WH-1  OY
WH-2 closed
WH-3  5Y 25 do NR       due to fledge 7/15
WH-4  4Y 25 do NR       due to fledge 7/15
WH-5  5Y 22 do NR       due to fledge 7/18
WH-6  6Y 21 do  NR      due to fledge 7/19
WH-7  0Y 30 do NR       due to fledge 7/10
WH-8  5Y 24 do NR       due to fledge 7/16
WH-9  4Y 25 do NR       due to fledge 7/15
WH-10  4Y 22 do NR     due to fledge 7/18

July 14  Finished up the last of the nest replacements and checks these past couple days.  The really hot weather broke about 5 days ago. The martin nestlings seemed to endure the very hot (highs in the low to mid 90’s for several weeks) weather well, and it looks to have been a successful breeding season so far. Near-final nest counts (with 1 or more nestlings due to fledge) are as follows:

514 Painter:                    8 pairs
Harrison Hills Park:    47 pairs (still 2 nests with eggs that could hatch)
Saxon Golf Course:      16 pairs
Crooked Creek Lake:   15 pairs

Total:    86 pairs

I will begin monitoring the Lock 4 roost site in several seeks to see if the martins begin gathering there again. I would expect numbers to be down due to the martin-killing weather of April and early May, when many martins perished. Two landlords in adjacent counties lost almost all the martins present at their backyard colonies.

Now that the field work of the 2020 season is over, I plan to write several new articles for this website.

Checked the bluebird house and found 3 eggs. She is on her 3rd brood of the season!

July 15  Painter Ave.: A ton of activity at the backyard colony this morning as 3 martin nests are fledging. At 2:10 PM, I spot FOUR Barn Swallows cavorting. They go in and out of the big shed, entering and exiting repeatedly through the windows and doors! The Barn Swallow vocalizations are not even playing. I turn them on but do not see these barnies go near the speakers or decoys. I have had one pair of nesting Barn Swallows for the past 5 years (2015-2019), but none this year. The pair in 2019 did not breed successfully. (The nestlings jumped or were pushed out and had mite infestation.) Plus, I think the very cold spring of 2020 killed a lot of barnies. I plan to place game cams in both sheds to record the frequency of visiting barnies. I think the martin activity probably helps to attract barnies too. Swallows attract swallows!

July 19  HOT High 95 degrees. Painter Ave.: As of 1:00 PM, all nests have fledged! Very quiet in the afternoon. I did nest replacements and found quite a few shells in ShellsCloseDimemost nests. I was SHOCKED that hardly any martins returned in the evening! Maybe 2 or 3. It seemed like a family appeared (5 martins or so) briefly but didn’t seem to roost here. I’ve had 7 nests fledge in the past 5 days and martin parents normally bring their fledglings back to the natal cavity to roost just before dark for 1-2 weeks, so my yard should be rocking with many (30-40) roosting martins, just before dark, but I’m stunned that so few have returned! I must assume it is because of the extreme heat! Perhaps the heat has caused them to begin roosting in the trees at pre-migratory roosts like the one at Lock 4 in Natrona, earlier that normal. Or perhaps the parents are roosting with their nestlings individually. I will try to visit the Lock 4 roost site on Tuesday to see if any come in to the trees at dusk.

July 21  High 89 degrees. humid. Crunched some numbers today and came up with average fledge dates for all 4 colonies I manage:

514 Painter:                    8 pairs       Average fledge date – July 16th
Harrison Hills Park:    47 pairs      Average fledge date – July 18th
Saxon Golf Course:      16 pairs      Average fledge date – July 21st
Crooked Creek Lake:   15 pairs      Average fledge date – July 24th

Interesting to note that the colony in my backyard had the earliest fledge date and the one furthest from my home – Crooked Creek (25 road miles), had the latest. Many factors involved, I’m sure, but we had a martin-killing spring and I was able to get more supplemental/emergency feedings to the martins closer to my home, perhaps allowing them to start nesting a little earlier

4:00 PM Painter Ave.: Two Barn Swallows cavort around the yard and neighborhood for a good 10 minutes. I did not see them enter either shed but I was not watching the whole time. Seems like they were really checking out the decoys and barnie vocalizations.

8:30 PM – 9:00 PM Lock 4 Roost site on River Rd. in Natrona, PA. I decided to check out the Lock 4 premigratory Purple Martin Roost site to see if any martins were yet present. I had texted one of the Lock workers earlier in the day to ask if he’d seen any evidence of roosting activity (droppings, dead martins, etc…) and he said yes there were quite a few droppings under some trees already and a few dead birds. So I was excited and when I arrived and parked in the parking lot next to the Lock yard, I began hearing martin vocalizations around 8:40 or so. I saw about 300 martins in loose groups, which eventually tightened. The first wave came into the treetops at 8:57 PM, followed by another wave at 8:58 PM. I saw a small group still in the air at 8:59 PM. I also saw several small waves of starlings (100-150) come into another nearby tree around 8:45 PM. A Harrison Township police officer stopped to check me out and I explained about the roost. He was very nice. He didn’t say I couldn’t park in that lot, so anyone wanting to view the roost would probably be OK to park there, I’d say, even though the lot is owned by ATI (Allegheny Ludlum Steel Corp.)  It’s a very big, largely empty lot.  But I’d stay close to your vehicle and “be aware of your surroundings.”  Large trucks sometimes enter and exit the lot.

60 of the 86 pairs at the 4 martin colonies I manage have already fledged, so considering each pair and their fledglings = 5 martins, and there are 60 pairs, the 300 number could just be “my” martins – I don’t know! Many if not most adult martins in southwestern Pennsylvania present at colonies other than mine were killed by the cold weather in April and early May, so it will be interesting to see how big the roost gets this season.

As you may recall, the martin housing was removed from the Lock 4 site back in early May, so I am relieved the martins are still gathering and roosting here even though it is not an active breeding site anymore.

July 22. 8:15 PM – 9:00 PM Saxon Golf Course colony, 1 mi. south of Saxonburg, PA. High temps for the past couple days in the mid to high 80’s. I visited the Saxon colony this evening to determine if what happened in my backyard colony (families not returning to roost in the several days after fledging) was also happening here. I theorized that the martins in my backyard colony on Painter Ave in Natrona Hgts. were not returning to their natal colony to roost either because of the extreme heat or because my backyard colony is only 1.3 miles from The Lock 4 roost site, and the parents were just taking their fledglings to the roost to roost! Other notes: (Saxon):

Unlike my backyard colony, there was an abundance of post-fledging, before-dark activity at the Saxon colony, where 12 nests have fledged in the past 5 days, and 5 of these nests have fledged in the past 3 days. At 8:30 PM, about 40-50 martins were circling the site and almost all had landed on and entered the housing by 8:50 PM.  So why did the Painter Ave. martin families not return in this fashion? At least two possible reasons: 1) The extreme heat caused them to want to roost in trees instead, and they chose the trees at the roost, only 1.3 miles away…or 2) The proximity of the colony to the roost, only 1.3 miles away, regardless of the heat, caused them to choose to roost there. I don’t remember this happening last year so I lean towards reason 1, but it could be a combination of heat and proximity. Keep in mind also that the roost site is right on the river, with plenty of opportunity for splash-bathing and drinking on the fly in the 95 degree heat. The relatively small number of martins already gathering there (a couple hundred) would make it possible to keep track of their fledglings.  Thanks to Ornithologist Jamie Hill for his input on this matter.

Of course another big difference between the two colonies is distance from the roost. The Saxon colony is 8.7 mi. NNW of the Lock 4 roost, whereas the Painter colony is only 1.3 miles north. Since the temperature has moderated a good bit (highs in the mid 80’s as opposed to mid 90’s), it’s impossible to say for sure why the Painter colony martins did not return much after fledging, but I suspect it may be a combination of heat and roost proximity.

July 26. Hi 93.  very hot and sunny

Noon. 514 Painter. Walked out into the front yard and heard one martin very high in the sky. I could not see it. There is activity at my backyard martin house almost every morning – anywhere up to a half-dozen martins whooping it up around the martin house – parents doing post-breeding cavity defense or subadult males trying to stake a claim for next year, I guess. They always disappear in the afternoon and I wonder where they go and what they are doing this time of the day. (1 – 7 PM)

8:15 PM – 8:52 PM Harrison Hills County Park, Environmental Learning Center Purple Martin colony, Natrona Hgts., PA. All but one of the 47 nests have fledged and I arrived to observe how many families of martins returned to roost at their natal colony. Most parents bring their fledglings back to the natal cavity to roost for about a week, at least 4-5 days. 10 nests have fledged in the past 4 days; 8 of these nests have fledged in the past 3 days. Considering each martin family consists of about 6 martins (2 parents and 4 fledglings), and considering 10 nests have fledged in the past 4 days, I should see about 60 martins (6 x 10) coming in to roost just before dark, but I never counted more than about 20 martins between 8:35 PM and 8:47 PM, about a third of how many I expected to see. The Harrison Hills colony is 3.1 miles north of the Lock 4 roost.

As you recall, I was shocked when barely any martins returned to roost at my backyard colony at Painter Ave. In Natrona Hts. on July 19th, when I should have had about 30-40 returning. I thought perhaps the heat (mid 90’s) and proximity to the Lock 4 premigratory roost (1.3 miles) site had caused the parents to take their families to the Lock 4 site instead. (See entry for July 19). On July 22, I visited the Saxon Golf Course colony which is 8.7 mi. from the Lock 4 roost site and found a normal amount of returning martins (See July 22 entry).

I suspect the proximity of the Harrison Hills colony to the Lock 4 premigratory roost site (3.1 miles), coupled perhaps, again, with the heat (hi 90 degrees today) is responsible for the lack of returning martins. I suspect they are joining the roost at the river instead of returning to their natal colony site, just like at my backyard Painter Ave. colony.   Perhaps there is an inverse correlation between a colony’s proximity to a large premigratory roost site and the length of time (number of days) parents bring their fledglings back to the natal colony. In other words, the closer a colony is to a large premigratory roost, the shorter the time parents bring nestlings back to the natal colony after fledging.

Aug 02   Observed 2 Purple Martins drifting high overhead (150 ft.) towards the Lock 4 roost at around 7:30 PM

Aug 04  Hi 83.  some sun, some rain, windy.  Even though my last martins fledged two weeks ago, I still see or hear martins almost every day, usually in the morning, while lying in bed, still half-asleep. It is not unusual for small groups of 3-5 to come screaming in like banshees, landing of the martin house and swooping around the yard. Very cool! Sometimes, in the early afternoon, I can hear one calling very high in the air, as I walk around in my yard, but cannot see it. haunting feel.

I intended to observe the Lock 4 roost this evening (approx. 1 mile SW of my house), but decided to go biking instead. At the end of my ride, as I was nearing my house on Painter Ave., I observed a movement of at least 50 martins drifting in a loose flock towards the roost at a height of about 100 ft. at 8:07 PM. The flock flew over at 903 Painter Ave., about 1/4 mile west of my home at 514 Painter Ave. Interestingly, they were coming from the direction of the Harrison Hills County Park colony, about 1 mile north. I saw more drift overhead from a northerly direction as I got home. I often see martins drifting over my property in the evening in 2’s and 3’s at around this time in the evening, at this time of year, heading for the roost no doubt. I’m sure I could create a staging area on the overhead wires around my property,  a 3/4 acre corner lot about 1 mile north of the roost,  if I were to play martin vocalizations (like we did at Beach 11 of Presque Isle back in the day), but I don’t want to annoy or alarm my neighbors!

Aug 06  Warm. sunny.  While checking the Harrison Hills colony site, I found what I think is a Great horned Owl (GHO) feather. I know there is a GHO nest nearby, and I have feared GHO predation for the past several seasons as the colony has grown large (35 pairs in 2019 and 47 this season), but I have not had any predation as of yet. Perhaps the very cold spring caused the owls to get a late start.

Aug 07  High mid 80’s. Sunny. 11:30 AM.  Observed 2 Barn Swallows investigating my site here on Painter Ave. They buzzed the barnie decoys and barnie vocalization speakers, and entered both sheds at least twice, but neither game camera captured an image. They were on site for at least several minutes.

Aug 08  Sunny warm. 514 Painter. At 11:52 AM, I spot a Barn Swallow swooping around near the barnie dekes and vocalizations. Also, 2 martins present. Did they all come in together? (I have seen then travel together in the past.) The martins are subadult males and land together on WH-6. The barnie leaves after a few minutes but the SY-M martins bum around until 12:18 PM

Aug 09  High mid 80’s. Sunny. 8:00- 9:00 PM

Harrison Hills Park, Natrona Hts. Cleaned out old nests and lowered houses. Found another half-dozen shells in various nests. A large hawk flew out calling over the colony site at height of 50 ft. Red-Shouldered maybe? It is big and had a nest in the trees about 100 ft. from the colony.

Saxon Golf Course. As I was cleaning out old nests (and removing 3 more House Sparrow nests) I found 1 unfledged nestling in WH-26 which only had eggs on last nest check (July 12), so this colony actually had 17 nesting pairs, not 16. Found 1 shell, probably from pond only 100 ft. away. So many House Sparrows! I really need to think about trapping the adults next year as they are RELENTLESS in renesting when just their nests are removed.

Lock 4 Roost Site, 1 River Rd., Natrona, PA.  I estimate 1000-2000 martins present. When I first arrived, I noticed several hundred starlings lining the overhead wires just outside the Lock yard fence on River Rd. Around 8:00 – 8:30, they flew, in several groups, into the roost trees that the martins use. I used my phone to video a large flock of martins swirling in the sky above the river (150 feet?). The video (best viewed on a cell phone or hi-res. monitor because the martins are very small!) is at

There is also at least 1 Peregrine Falcon present. It is sitting on the tops of several telephone poles near the roost trees and going after martins as they come into the trees. I am standing just below one of these poles and clap my hands to see if the falcon will flush but it doesn’t budge! The first (smaller) wave of martins comes in to land in the roost trees at 8:36 PM. It is nearly dark before the second, larger wave comes in at 8:48 PM. I wonder if the Peregrine is keeping them up longer, because it seems they came in sooner last year.

I also saw several other species of swallows at the roost – Northern or Bank, I think. It would be great to see Barn Swallows joining the roost, as I am trying to get a few pairs to nest in my sheds.

Aug 10. 514 Painter. Two martins hanging around between 11:00-12:00 PM. Were on WH-6 again – probably the same two SY-M’s that were here on Aug 08.

Aug. 11  514 Painter. 2  subdult males (SY-M’s) present at 10:50 AM….maybe the same 2 as yesterday? my “subbie boys” haha. They were hanging out on the same porches. I played the martin vocalizations (dawnsong and daytime chatter) and they immediately reacted – going from the overhead wires on Lincoln St. to the porches of the T-14 and displaying by poking their heads into the entrance holes of the compartment, and looking all around and calling. Both still here at 11:58 AM. At 12:26 there were 3 martins, and at 12:42 there were 4 martins. One seemed like a stranger because it just swooped all around but didn’t land. I went back to the barn swallow vocalizations. This experience reinforced my belief that if I played the martin vocalizations around 7 pm, I could create a staging area by attracting many martins to perch on the overhead wires before going to the roost.

Aug. 16  514 Painter. 8:14 PM. As I walk outside I see about 20 martins drifting in very loose formation towards the roost at a height of 60-80 ft. They are coming from the northeast. There may have been more…looks like I just saw the tail-end of this movement.

Aug. 19  Lock 4 Roost Site, 1 River Rd., Natrona, PA. My friend Doug Falk from Fombell, PA visited the roost and happened to meet a photographer and reporter from the Tribune Review. He saw a Peregrine attempt to take a martin but failed. He estimated 2000 martins came in to roost.

Aug. 27  Lock 4 Roost Site, 1 River Rd., Natrona, PA. I meet with two staffers from the Tribune Review (a reporter and a photographer) at the roost but very few martins come in to roost. I suspect it is because just 2 hours earlier, there was a very severe thunderstorm with rain, and the martins hunkered down and roosted where ever they were just before the storm hit. We did see a Peregrine Falcon fly over.

New Purple Martin Roost in Natrona, PA along Allegheny River; Video and Information. 2019

Ken Kostka
American Swallow Conservation Association

For the past three seasons (2017, 2018, 2019), Purple Martins have formed a premigratory roost in the trees of the US Army Corps Lock & Dam #4 facility in Natrona, PA. This video was taken in late August 2018. The roost has grown to 5000 – 7000 martins, which gather in the evening into large swirling formations and eventually land in several large trees on the Corps grounds.  The roost forms all through the month of August with peak numbers occurring in mid-august.

The martins begin gathering about an hour before dark, streaming in from all directions, landing on wires and and swirling in large formations several hundred feet above the Allegheny River, eventually landing in the trees in spectacular fashion just before dark (watch video above). They disperse in the pre-dawn hours, flying off in all directions to distances of up to 100 miles to feed and explore the countryside, then regather again in the evenings. Towards the end of August, individual birds or very small groups eventually depart for South America.  This is the only known roost in the Pittsburgh area. The only other two known roosts are in Presque Isle, PA and in Waynesburg, PA.

There is a 20 pair Purple Martin colony on the grounds. This colony was established in 2005 with one breeding pair that was displaced from the Saxon Golf Course colony near Saxonburg, PA as part of a project intended to establish new breeding sites. There are several other articles about the Lock 4 colony and the displacement project on this website. I hope to publish more information and videos here about the roost in the future as time and energy permit.

0000003900000124I would find some dead martins under the main roosting tree every morning. Some had no visible marks but some were eaten. I wasn’t sure what had eaten them or whether whatever had eaten them was simply scavenging martins that had died and fallen or whether predators were climbing the roost tree and killing the sleeping martins. So in 2018, the Lockmaster gave me permission to place an electric fence around the main roost tree in an effort to discourage climbing predators. This did seem to deter most predators, but, as the one photo shows, an at least one raccoon got around the fence.DSCN3313


If you want to view the site with GoogleEarth, the address is:

1 River Rd., Natrona, PA 15065

There are also many articles with photos about the Lock 4 Purple Martin colony on this website.

Additional video of roost and Lock 4 facility:

video of roost (swirling formations) in August 24,2017:

video of martins bustling in the trees:

Below is GoogleEarth Photo of the Lock 4 facility, 1 River Rd., Natrona, PA on the Allegheny River in northeast Allegheny County.  The red lines converge in the lawn area containing the martin housing and the roosting trees. This is a restricted U.S. Army Corps of Engineers Facility, not open to the public. Viewing must be done from outside the fencing. The large parking lot to the east is a good vantage point. This is a large private parking lot that is usually pretty empty but I’d stay with my vehicle. The other viewing area is a small parklet just downstream of the Lock 4 facility. This parklet can only be accessed by way of a dead end alley. The entrance to this alley is 0.36 south of the Lock facility off River Rd. The parklet viewing area is better for watching the large swirling formations that form above the river, but the parking lot viewing area is better for watching the martins as they come down into the trees, also a spectacular sight. Keep in mind this premigratory roost forms only in August. Mid to late August is the best viewing time.


Additional Photos of Lock 4 Roost site:

Cat under roost tree before electric fence

Roost trees

Large metal tower that martins stage on

Electric fence with solar charger

Main roost tree second from left

Go here for 2020 updates on the Lock 4 roost:




Ken Kostka,
American Swallow Conservancy

These 18 pairs of Purple Martins died during a prolonged period of cool/cold weather. DON’T LET YOUR PURPLE MARTINS DIE !!!  When faced with three or more days of consistently poor weather (continuous rain or temperatures continuously below about 50 degrees Fahrenheit), Purple Martins begin starving to death because they do not have anything to eat.  Purple Martins eat only flying insects, such as flies, beetles, dragonflies, midges, butterflies, and the like.  When it rains continuously or the temperature gets below 50 degrees, these insects become inactive and the air is deprived of the martins’ only source of food. The only way to keep your martins from dying during these prolonged periods of foul, insect-less weather is to train them to eat large crickets, which can be purchased in bulk and shipped to you overnight.

Here it is in a nutshell: When martins have endured several days without food, they become desperate and will eat large crickets if you fling them into the air with a simple plastic spoon. You can also place the crickets on the porches of the martin housing, but flicking them into the air is much more effective in getting the martins to notice and eat them. So here’s what to do. Call Fluker Farms at 1-800-735-8537 or go to their website at  and order 1000 six-week old crickets. (1000 is the minimum purchase, and six-week old is the largest available). Have them shipped overnight by Federal Express or Airborne Express.  If you have a large colony or plan to feed them through a long period of cold weather, consider ordering more.  A martin will eat about 25 crickets per day.

The crickets will arrive LIVE in a cardboard box.  Put the whole box into a garbage bag and place it in the refrigerator or freezer for about 20 minutes.  This will knock out the crickets and make them easier to handle. (Trying to fling live crickets is difficult; they keep trying to escape.)

Locate your Purple Martins.  They may be hunkered down inside the housing. You may need to chase them out of the housing by lowering the house. Once they have landed on nearby perches, phone lines, etc…, place a cricket into the plastic spoon and catapult it (fling it) high and past the starving martins. You may need to fling several dozen before one or two martins starts to go after the flung crickets. But once one martin starts going after the crickets, the others will imitate and before you know it, they’ll all be feeding. Once they have been trained to eat crickets, you can substitute scrambled egg! But you must start with crickets; this is because crickets look like grasshoppers – something that martins normally eat. The wings and legs are critical because theses body parts allow the martins to recognize the crickets as a potential food item!

Check newspaper for weather forecast  Monitor you birds closely during poor weather. Look for listless behavior and drooping wings. Your birds may resort to “communal cavity roosting” which means they pack themselves into one cavity for shared body heat. Don’t wait too long to act. When martins start falling to the ground and dying, it’s usually too late!

If you are not going to feed, then don’t lower the house, and hope for the best but check the housing as soon as the weather breaks and remove any dead martins that might be blocking the exit of live ones huddled inside.

IMPORTANT: Once you have trained your martins to accept tossed crickets, you can substitute marble-sized pieces of scrambled egg, which is much cheaper and more readily available!!  Keep in mind, it’s much easier to fling the crickets/egg with a plastic spoon instead of by hand/arm. To make scrambled egg in a microwave, place eggs in a large glass (microwavable) bowl, mix, microwave for 1-2 minutes, mix again, and repeat until egg is fully cooked (but no overcooked). Once the martins have learned to accept the egg when flung into the air, you can place it on a feeding tray or platform. Doing so saves the martins from expending energy by flying around waiting to get their chance at a piece of egg.

IMPORTANT: With the increase of emergency and supplemental feeding, some martins at an untrained colony may already be trained to eat egg without you being aware of it! This is because they may have dispersed from a colony that was already trained to eat scrambled egg.  Most landlords whose colonies are trained to accept supplemental feedings use scrambled egg because it is MUCH cheaper and more readily available, so thousands of martins all across the USA are already trained to eat scrambled egg.  So try tossing (flinging with a plastic spoon) several marble/pea sized chunks of scrambled egg towards the hungry martins. If there is a martin trained to eat egg (and they are hungry), they will go after the egg and others will imitate, just like with the crickets.


More supplemental feeding articles: 

40 Starving Martins Eat 900+ Hand-Tossed Crickets at Amish Colony