The Lock 4 Colony in Natrona, PA; Year 2 Dynamics. 2006

Ken Kostka
American Swallow Conservancy


In the article titled “Purple Martins Breed in Natrona, PA, in 2005, as a result of Forced Dispersal Project”, I chronicled the breeding season of the first pair of Purple Martins to nest in northern Allegheny County in over 30 years. That subadult pair arrived in mid-June of 2005 and successfully fledged four nestlings.  At least 17 additional martins visited the site on one or more occasions between June 17th and August 20th, 2005. I was in a state of perpetual suspense during the off-season, because a “one-pair colony” can either grow into a multiple-pair colony or fizzle into a “zero-pair colony”, depending on the survival and site loyalty of the lone breeding pair, as well as their success in attracting other breeding martins. 2006 would prove to be another very exciting year, with more surprises, questions, disappointments, and successes.

Summary  On April 23, 2006, the first Purple Martin of the season – an adult male – appeared at the USACE (US Army Corps of Engineers) Lock 4 colony along the Allegheny River in Natrona, Allegheny Co., PA.  The site consists of two wooden T-14’s, one with gourds hung underneath. This adult male did not attract a mate until May 5, and by May 14, there were four martins staying at the site. A period of continuous cool, wet weather began on May 15 and lasted until May 23. During this time, the martins were fed crickets, mealworms, and scrambled egg on a daily basis, and their numbers grew to 18 martins by May 21. By June 5th, there were 6 nests, 4 of which contained 1 or more eggs. However, three breeding martins died of unknown causes over the course of the next ten days – one from each of three separate nests – causing there to be only 3 breeding pairs. These three pairs went on to reproduce successfully, fledging 14 of 15 nestlings. I  have highlighted in red any observations or activity that I consider to be especially significant or noteworthy. A discussion/analysis of these noteworthy observations and events appears at the end of this article, as do several other summary tables.

Key terms and abbreviations: SY-M = subadult male, a one year old male, a first year breeder; SY-F = subadult female, a one year old female, a first year breeder; ASY-M = an adult male, two years old or greater, all dark plumage, they are in their second or greater breeding season; ASY-F = an adult female, two years old or more, they are in their second or greater breeding season; HY-U = Hatching Year, sex Undetermined (a fledgling). WH-13 = compartment #13 in a wooden house (T-14); T-14 = a type of wooden house with 14 compartments, named after its inventor, Andy Troyer; Snyder Excluder = a type of entrance hole designed to exclude starlings, named after it’s inventor, Duke Snyder; Conley Excluder = a variation on the Snyder Excluder, believed to allow easier entrance by martins, but also known to occasionally admit starlings. All temperatures in Fahrenheit scale.

The first Tree Swallows returned to Natrona on March 30, 2006, and the first Purple Martins returned to the Saxon Golf Course colony, 8.7 miles north, on April 1st.  The oldest male martins (5-7 years old) return to southwestern PA in early April, and subadults, in early May;  By April 20th, there were over 20 martins back at the long-established 28 pair Saxonburg colony, but still none at Natrona. The pair that nested in Natrona last year would now be two-year old birds, not overdue until late April. I would recognize the male of the 2005 Natrona pair because he was banded. He had a yellow aluminum leg band with the code K404; the female was unbanded.

Although no martins had yet arrived in Natrona, four of the twenty martins back at the Saxonburg colony had been frequent visitors to the Natrona site in 2005. They were K279 ASY-M, P524 ASY-M, K415, ASY-M, and K479 ASY-F. The last three martins were SY’s in 2005.  K279 and K479 were displaced breeders; K415 and P524 were non-breeding floaters. These four birds from Saxon were spotted at the Natrona site a total of 32 times between June 18th and August 10th, 2005, an average of eight days each.  I had hoped that at least one or two of these frequent visitors would breed in Natrona in 2006, but none had yet been seen there. All four went on to claim new compartments and breed successfully at the Saxonburg colony. Interestingly, two of these birds – K415 and K479 – paired and nested together. None were ever spotted again at Natrona.

Finally, on April 23, at 5:30 PM, I spotted a pair of adult (ASY) martins at the Lock 4 site in Natrona. I naturally assumed it was the same pair that nested successfully there in 2005, but I was wrong! In fact, they were two totally different martins.  The male was not yellow K404 but rather yellow K384.  He had been spotted  two days earlier at the Saxonburg site. Banded as a nestling at the Saxonburg colony in 2004, he was spotted only twice in 2005 – on June 20th and 23rd  at the Natrona site. The female was yellow A544, who had been banded as a nestling in Shelocta, PA in 2004. She apparently didn’t care much for K384 or the Natrona site, because  I never saw her again. K384, however, persisted. He was present at the Natrona site on 4/25, when I observed him chase Tree Swallows off both T-14’s. He was alone on 4/28, 4/29, 4/30, 5/1, 5/3, and 5/4. (On 5/2,  he was briefly joined by another ASY-M). It should be noted that I was only present for a short time in the early morning on most days, and other martins could have visited. Also, I assume that K384 often left to recruit martins from other sites.

On May 5, to my great relief, K384 was spotted with another ASY-F! They emerged together from WH-16 (compartment #16) at 7:00 AM. This adult female was unbanded, and I suspected she was not the same female who bred here last year because she was very dark underneath, and two year old females are typically fairly light. Also, she seemed to favor the newer T-14 rather than the one that was nested in last season. But there is no way to be certain she was not last year’s female, because (like last year’s female) she was unbanded.

May 6, 2006  Cool. High of  60F.

7:30 AM.  The pair emerges from WH-16

10:00 AM.  I put eggshell and mealworms on the feeding tray, and the female lands almost immediately and picks up eggshell and flies to the porch of WH-16. The male enters and she follows him in with the eggshell. I put crickets and mealworms on the feeder, and also tossed crickets, but I didn’t see them eat any, despite it being a cool morning.

1:15 PM.  The pair is still present at the site.

May 9, 2006  Cool in the AM. High of 72F.

7:25 AM.   The pair emerges from WH-25.  Apparently they are uncertain about which compartment they want, since they slept in WH-16 last night. I am playing dawnsong from a small speaker inside WH-28, and there is a mirror in the compartment of WH-27, just above WH-28.  Are these stimuli having some effect on the pair’s (especially the female’s) choice of compartment? What cavity will they finally choose?

8:15 AM.  The female ate a cricket from the feeder.  I have been placing frozen crickets in the feeder trays at 11:30 PM when I come at night to check and take in the House Sparrow traps. By the early AM, they are thawed but still very fresh since it has been very cool overnight. The martins have been eating some, but I later discovered that House Sparrows were eating most of them, so I discontinued the practice.

5:00 PM.  A 2nd ASY-M is present at the site! He is unbanded, and still present at 7:00PM.  He hangs out mostly on T-14 #1, which contains compartments WH-1 to WH-14. I put many twigs on the feeder for the pair’s convenience in the event that they decide to start nestbuilding.

May 10, 2006 

There are 3 martins present in the AM. Yellow K384 is trying to get the female to start nestbuilding by carrying a twig around in his beak and landing on the porches of WH-15, 16, and 17. Both males vie for her attention by “whooping it up.” They both fly around and land on multiple porches, then entering and exiting the compartments.

6:40 PM.  During a nest check, I discover many twigs (from the tray) inside WH-16.

7:40 PM   Unbanded ASY-M picks up twig from tray and goes into WH-7.

8:00 PM    Yellow K384 picks up twig and lands on lamp-post next to female. She chases him off.  He takes it into WH-16.

8:15 PM    The pair enters WH-16.

May 11, 2006  Rained overnight; cooler and windy, but nice.

8:45 AM.  The unbanded ASY-M shows up with what appears to be a new female. She flies around and hovers but is reluctant to land. This new female is much lighter underneath. She is just a little dark underneath. She could be the same unbanded female that bred in this same compartment last year (when it was numbered as WH-14). She enters and exits WH-7 multiple times with the unbanded ASY-M.

9:30 AM.  The original pair returns to T-14 #2, exiting and entering multiple times, while the new pair is inside T-14 #1 (WH-14). Eventually they notice each other and the four of them fly around together whooping it up. The darker female lands on the other house and K384 follows. She seems enthralled by the new female (or male?) and the males get into a few brief fights. Eventually, she goes back to her own T-14.

10:25 AM. An SY-M shows up and pokes around. I see the dark female on WH-24.

10:45 AM  Very windy. All martins gone. Still gone at 11:30 AM. Then it rained almost constantly until dark.

May 12, 2006  cool. 48F

6:30 AM  5 martins present. I put mealworms and crickets in the feeder, but none landed to eat. At the Saxonburg colony, I put eight scrambled eggs and a pint of mealworms in the feeder and there was a feeding frenzy. Could it be that since these martins are next to a large body of water (the Allegheny River), they are finding more to eat during cool weather than the ones as Saxonburg?

May 13, 2006

  1. Four martins present (ASY pair, ASY-M, SY-M)  I put crickets and mealworms in the feeder. K384 landed three times and ate 1 mealworm each time.  None others landed while I was there.

May 14, 2006  warm in AM, but it became windy and rained hard from 4:00 PM until dark. The weather will remain cool and wet for the next nine days.

Same 4 martins present in the AM, but Wayne (lock worker) told me he saw 5-6 martins at 3:30 PM!

May 15, 2006  Cool. Rain

5:40 AM. I placed crickets and mealworms on the feeder but had to drill drainage holes to let the rain out. When a House Sparrow landed to eat a cricket on the feeder, an ASY-M flew down, chased the sparrow off, ate a mealworm, and flew off. When the House Sparrow came back, the other ASY-M flew down, chased it off, and ate several crickets.  So the House Sparrow seemed to stimulate the martins to use the feeder. Three of the five martins seem to be feeder-trained. A similar thing happened at the Saxonburg colony last season. When I placed scramble egg on the feeder, the martins were reluctant to land and eat, but when an American Robin landed and began to eat egg, a martin flew down as if to chase the robin off and began poking around in the trays. I felt this was a positive occurrence, as it seemed to teach the martins that the feeder was a food source.

3:30 PM. 5 martins present (2 ASY pairs and an SY-M).  3 martins ate at feeder. The new ASY-F landed and watched the others eat. The SY-M did not eat.

May 16, 2006  Cloudy. Light rain. 3rd day of cool weather

6:30 AM. 2 of the 5 martins are sitting on the feeder when I arrive. I decided to toss crickets and many were eaten. Even the SY-M ate some. I can’t put crickets and mealworms on the feeder because the starlings and House Sparrows have learned to land and eat them, and I certainly don’t want to encourage or attract either of these two harmful species..

4:00 PM  There are 6 martins. A new ASY-M is present. All 6 martins are eating tossed crickets!

May 17, 2006  Cool. Rainy. 50’s

6:30 AM.  8 martins on the T-14’s!! 3 ASY-M, 2 ASY-F, 2 SY-M, 1 unknown (I didn’t get all eight to sit still long enough to tell.) Almost all are eating tossed crickets. Fantastic!

3:00 PM.  I toss-fed crickets again to 5 martins that were present.

May 18, 2006  Rain, some sun, cool, windy, 50’s

6:30 AM.  9 martins present.  Almost all ate crickets that I tossed in a light rain.

3:00 PM.  0 martins present

5:00 PM.  4 martins present. Toss-fed crickets

7:30 PM.  7 martins present

8:00 PM.  Just after I toss-fed crickets, all 8 martins flew off and landed on the Trio Castle on the lock wall. A new SY-F had arrived and they were all making a big fuss. Eventually, all eight martins came back to the T-14’s and went inside around 8:30 PM.

May 19, 2006  high of 50F, rain

6:15 AM.  7 martins present. I toss-fed crickets.  A starling landed on a T-14 and went after a tossed cricket and caught it!  The starlings and House Sparrows must really be getting desperate. They gather whenever I start to feed the martins and go after the crickets that land on the ground. I have been catching dozens of mostly female OLYMPUS DIGITAL CAMERAstarlings in my bait traps with bread. I normally catch House Sparrows in them.

3:30 PM. 11 martins present. Toss-fed crickets. The martins are also taking many tossed mealworms for the first time. A Barn Swallow also ate a few tossed mealworms. I have also had Tree Swallows take food during these toss-feeding sessions. One SY-F is sitting on the fence with wings drooped.  Is she stuffed and relaxing or ready to die?

May 20, 2006  cool, cloudy. sunny in PM

7:00 AM.  12 martins present. I toss-fed a large quantity of crickets and mealworms. All of the martins are taking them.

12:00 PM. I fed again. Only 7 martins present. The original pair (K384 and dark female) are not present.

May 21, 2006  Cold!

7:30 AM. 16 martins present.  I toss-fed crickets. ( I also fed at three other colonies today – Saxonburg, Moraine State Park, and Shelocta.)

8:00 PM.  18 martins present! Fed again. Only one of these 18 martins is banded – Yellow K384 ASY-M, despite the fact that almost all of the martin nestlings within a 30 mile radius have been banded for the past 4 years. Scientific Advisor Dan Ariola suggests that these martins are stalled migrants, waiting out the cold weather. This would mean many of these martins from colonies much further north. It would make sense that the Allegheny River serves as a migrational corridor.  This large body of water could function as both a geographical landmark and a feeding area for migrating martins.

May 22, 2006  Cold!

7:00 AM.  15 martins present.  Toss-fed crickets

8:00 PM.  15 martins present. I ran out of crickets and had to resort to tossing Sierra Exif JPEGmarble-sized pieces of scrambled egg.  The martins at this site had never been fed egg, but they started eating it almost immediately. Based on a similar feeding experience at the Moraine State Park colony on April 26, 2006, which I will describe in an article titled “Emergency Supplemental Feeding During the 2006 Season” (not yet online), I have come to the conclusion that the best way to get martins to eat scrambled egg is to toss it. Once martins are trained to accept tossed crickets and mealworms, they apparently come to “trust” the  tossed egg, whereas they would be reluctant to pick it up from a feeding platform.

May 23, 2006  Cold, windy, sunny in the AM. Weather got nice in the PM, finally.

7:30 AM.  12 martins present. Ate tossed egg (exclusively)

11:00 AM. Martins ate more tossed egg.

May 24, 2006  Sunny. 70’s. nice.

7:00 AM.  I counted 11 martins and toss-fed egg but they didn’t eat much.

4:00 PM. Did 1st nest check. Partials in WH-16 and WH-25 (the original pair can’t decide) Green leaves only in WH-3, 7, 10, 14 (bottom compartment of each section in T-14 #1) Based on activity alone, a pair is claiming a modified Supergourd (porched with Conley excluder entrance) facing the river on T-14 #2, another pair is claiming WH-7, and an SY-M is claiming WH-10.  So there are 3 pairs and a spare, it seems.

May 25, 2006.  Rain, mid-50’s in the AM.

8:00 AM.  11 martins: 3 ASY-M, 4-5 females, 2 SY-M.  They ate 2-3 scrambled eggs despite yesterday being warm and sunny.

May 27, 2006 

9:30 AM.  10 martins ate 2-3 tossed eggs

May 28, 2006

9:00 AM. The martins are nest-building like crazy, taking corn fodder off of the feeding trays.

May 29, 2006

9:30 AM. I spotted a banded SY-M, only the second banded martin (out of at least 18) to be seen this season. He is a Yellow K566 – one of the four nestlings that fledged from this Natrona site last season!

June 1, 2006


WH-06 = partial nest
WH-07 = nest with green leaves
WH-10 = nest with 1 egg
WH-15 = trace nesting material
WH-16 = nest with green leaves (K384 and dark ASY female eventually laid 6 eggs in WH-15)
SG – 3 = green leaves

There are several other compartments with green leaves or trace nesting materials, but I am excluding them since they never received eggs.

June 4, 2006  Rained all day. I toss-fed egg.

June 5, 2006  Nest Check I have placed the age of the MALE/FEMALE next to the nesting cavity

WH-06     ASY/ASY     nest
WH-07     ASY/ASY    3 eggs
WH-10     SY/SY         3 eggs   *female found dead on nest*
WH-15     ASY/ASY    2 eggs
WH-24     SY/SY         nest
SG-3        ASY/SY       1 egg

*The female found dead on the nest did not appear underweight. I failed to weigh her, but she appeared quite meaty. She did not have any apparent external injuries and there was no blood, so a starling attack is unlikely, although it cannot be ruled out. Furthermore, the nest was undisturbed and the eggs unbroken. No starlings were seen on the house, and none tried to nest in any cavity afterwards..

June 7, 2006 

8:00 PM. There is a SY-M here with a maimed foot that I saw this morning on a T-14 at Crooked Creek Park near Ford City, PA, 12.5 miles north. I know it is the same male because although he is unbanded, the maimed foot has a few small feather “stuck” to it. It is quite distinct and there is no mistaking it. The Crooked Creek site is uncolonized, but the dawnsong is being broadcast from a nearby building. He was seen again at the Crooked Creek site the next morning, and just about every morning for the next week.

June 8, 2006

I found a decaying martin next to the fence at the north end of the facility. It could have been anything but an adult male. It must have been dead 1-2 weeks. Was it a victim of the bad weather, sickness, or a hawk?

June 9, 2006  Nest Check

WH-06     ASY/ASY     nest with green leaves
WH-07     ASY/ASY    5 eggs
WH-10     SY/SY         3 eggs    (believed abandoned)
WH-15     ASY/ASY    6 eggs
WH-24     SY/SY         nest with green leaves
SG-3        ASY/SY       1 egg  (same as last time)

June 10, 2006  windy, cool, 50’s. I toss-fed egg several times in the AM.

June 11, 2006  high of 67F.  Cool in the AM. There are 5 ASY-M’s present.

I tossed egg but the martins didn’t eat much. It was relatively warm here compared to the Saxonburg colony, where it seemed quite cool and the martins were swarming around as I tossed egg, as well as landing on the feeding trays to take egg. Of course, there are at least half a dozen nests with young at Saxonburg, and the martins are feeding much of the egg to the nestlings. Also, perhaps the river pool – which is large body of water much like a lake – is acting as a heat sink, providing more flying insects to feed on, as well as warming the surrounding air. It just seems significantly warmer at the Natrona site

June 12, 2006  high of  70F. Toss fed a couple eggs at 7:00 AM. Again, not as cool here as at the Saxonburg colony.

June 13, 2006  Warm, sunny.

There are three banded martins present among the 5 nesting pairs and other non-breeders:

yellow K384 ASY-M (nesting in WH-15, banded as a nestling at the Saxonburg colony in 2004)
yellow K566 SY-M (non-breeder; banded as a nestling at the Natrona, PA colony in 2005)
yellow E027 SY-M (non-breeder; banded as a nestling at the Shelocta, PA colony, 22.5 miles WNW, in 2005)

Nestcheck 12:30 PM.:

WH-06     ASY/ASY    4 eggs
WH-07     ASY/ASY    5 eggs
WH-10     SY/SY         3 eggs    (believed abandoned)
WH-15     ASY/ASY    6 eggs
WH-24     SY/SY         female on nest (did not disturb)
SG-3        ASY/SY       2 eggs  *ASY-M found dead on nest*

The dead ASY-M in SG-3 could not have been dead for more than 1-2 days, but weighed 43 grams, suggesting he was sick, old, diseased, or a victim of the poor weather. Since there continued to be activity in the gourd, I assumed he was not the resident male – just as old ASY-M that had crawled inside the gourd to die. I recalled having seen what seemed like a rather scruffy looking ASY-M hanging around that gourd. As it turned out, the nest was abandoned, suggesting he was the resident male. As with the female found dead on June 5, there were no signs of external injury or attack and no blood. The eggs were unbroken and the nest was undisturbed. I had not seen any starlings on the gourd. In retrospect, it seems certain that this martin was not the victim of a starling attack, since he was about 10 grams underweight. He probably was sick.

June 14, 2006 

8:00 AM.  A new martin is seen for the first time this season. He is Yellow T213, an SY-M banded as a nestling at the Moraine State Park, PA colony on July 5,  2005 and seen at the Natrona colony on Aug. 8, 2005 as a fledgling (HY-U). The Moraine colony is about 30 miles NW of Natrona.

Yellow K566 SY-M also present in the AM.

June 15, 2006

7:00 PM. I find a dead ASY-F under a tree just inside the fence by the road, about 40 feet from the martin housing. She weighed 41 grams – about 8-10 grams underweight. Her wing looks a little disjointed but this may just be a result of how it was positioned when she died. Again, there are no visible signs of trauma or injury. Eventually, I determine that this is the female from WH-6 which contains a nest with four eggs. This is the third breeding martin to be found dead in 10 days. In ten days, the number of breeding pairs has dropped from 6 to 3.  Alarmed, I begin to suspect that perhaps starlings are responsible for these three deaths. I plan to arrive early tomorrow morning and monitor the housing from a distance to detect any starlings that may be depredating the colony.

June 16, 2006

6:30 AM. I park in the alley across the road from the lock yard, where I can monitor the martin housing from afar with binoculars. Some starlings are foraging in the grass below the housing (which is typical) and one or two lands briefly on the T-14 porches before dropping to the ground to forage. Although no starlings are seen trying to enter compartments or harassing martins, the starlings activity unnerves me, and I decide to replace the Conley Excluder entrance holes (on the active compartments) with Excluder II’s just in case the starlings are responsible for the martin deaths. The Excluder II is a more restrictive entrance hole; there have been reports from other landlords of starlings penetrating the Conley entrance. Around noon, I switch the entrances. The ASY female at WH-7 hesitates for about 30 seconds – bobbing her head in and out – then enters without any problem, as does the male.  The ASY female at WH-15 doesn’t even hesitate; she slips right in like nothing has changed, as does the SY female at WH-24. From this point on, no more martins are found dead.  All three remaining pairs go on to fledge young. But this may just be coincidence. With the help of Scientific Advisor Gene Morton, I conclude that these three martin deaths were most likely caused by something other than starling depredation. Several factors lead to this conclusion. First, there were no signs of injury usually associated with a starling attack on any of the three martins. Starlings typically use their long beak as a weapon to kill or injure martins, resulting in a bloodied head or back. Furthermore, none of the nests were disturbed; no eggs were broken, and starlings did not attempt to nest in any of the compartments in either of the two T-14’s. Second, at least two of the three martins were 8-10 grams underweight, suggesting that they died of sickness or disease. Several days later, however, a starling was seen peering into WH-7, before it was chased off by a lock worker.

June 20, 2006

7:00 AM.  9 martins are flying above the site when a Cooper’s Hawk flew through. It had been sitting in a tree and apparently spotted by the martins.

June 22, 2006

WH-06     ASY/ASY    4 eggs   (believed abandoned)
WH-07     ASY/ASY    1 egg, 4 nestlings that are either hatching day or 1 day old.
WH-10     SY/SY         3 eggs    (believed abandoned)
WH-15     ASY/ASY    6 eggs
WH-24     SY/SY         4 eggs
SG-3        ASY/SY       4 eggs  (3 eggs look old/spotty; only one looks new)

June 23, 2006

ASY-M carries eggshell half out of WH-15, indicating a hatch! I also saw a starling try to land on the T-14.

June 26, 2006

WH-06     ASY/ASY    4 eggs   (believed abandoned)
WH-07     ASY/ASY    5  nestlings
WH-10     SY/SY         3 eggs    (believed abandoned)
WH-15     ASY/ASY    6 nestlings
WH-24     SY/SY         4 eggs
SG-3        ASY/SY       4 eggs  (believed abandoned)

June 28, 2006

WH-07     ASY/ASY    5  nestlings – 5 days old
WH-15     ASY/ASY    6 nestlings – 4 days old
WH-24     SY/SY         4 eggs

June 29, 2006

8:00 PM. Saw several new martins at the site:

yellow K5?7 SY-M (not sure of second or third number, but K527 was spotted several days later)
yellow T344 SY-M
unbanded ASY-M

A lock worker tells me that there are many mayflies above the water. (See photo at right of closeup of two mayflies on window)

July 03, 2006

9:00 AM.  All three pairs are feeding young. I see 4 banded martins, one of which is a new arrival. I also see what I believe to be a new non-resident unbanded ASY-M and a new unbanded SY-M. :

yellow K501 SY-M banded as a nestling in 2005 at the Saxonburg colony, 8.7 miles OLYMPUS DIGITAL CAMERANNW
yellow K384 ASY-M
yellow E027 SY-M
yellow K566 SY-M

July 04, 2006 constant rain in AM., overcast, warm, a bit windy

The martins ate tossed egg and fed it to their nestlings. They ate about 2-4 eggs in the AM and again in the PM. The ASY pairs in WH-7 and WH-15 made constant trips to their nests with egg. They would hover over me as a sign they wanted more. (Eventually, all of their young fledged successfully, so I assume the egg supplementation was beneficial, or at least not harmful.)

I saw a new banded martin among the 4 banded birds:

yellow P944 SY-M banded as a nestling in 2005 at the Zeglin’s Dairy Farm colony in Mt. Pleasant, PA, 32 miles SSE)
yellow K501 SY-M
yellow K384 ASY-M
yellow ???? SY-M with blue anodized on right leg (probably E027 SY-M)

July 07, 2006  Warm, sunny.

There are many mayflies being brought in by the parents. 10-12 martins present:

yellow K384 ASY-M
yellow P944 SY-M
yellow K566 SY-M
yellow T??? SY-M (probably T213)
yellow K501 SY-M
2 unbanded ASY-M
2-3 unbanded SY-M
2 unbanded ASY-F

I observed yellow K566 sitting inside WH-15. Yellow K384 (the male of that pair) did not scold or attack him when he arrived with food!

July 08, 2006 Warm, sunny

Parents bringing in beakfuls of mayflies and many dragonflies. Much martin activity – about 15 martins present. The banded include another new bird:

yellow K527 SY-M banded as a nestling in 2005 at the Saxonburg colony, 8.7 miles NNW
yellow K384 ASY-M
yellow K501 SY-M
yellow P944 SY-M
yellow K566 SY-M
yellow T213 SY-M

Yellow K566 was seen entering another cavity with nestlings – WH-24.

I did a nest check and banded the nestlings in WH-7 and WH-15:

WH-7    5 young banded; nest replaced
WH-15  6 young banded; nest replaced
WH-24  4 young 7 days old; nest replaced

July 10, 2006 Warm and sunny

7:15 AM. Another new band: Yellow K493 SY-M banded as a nestling in 2005 at the Saxonburg colony, 8.7 miles NNW

8:45 PM. yellow T213 SY-M

July 12, 2006 Rained on and off all day. I fed egg to the parents, who took it to their nestlings (all three nests)

July 13, 2006  hot, humid

At 6:00 PM., I saw:

yellow K566 SY-M
yellow K493 SY-M
yellow E027 SY-M

July 14, 2006 

At 7:00 AM. There are 4 ASY-M’s present. The parents are going out and coming in very quickly with beakfuls of insects. I saw:

yellow K566 SY-M
yellow K501 SY-M
yellow E027 SY-M

July 17, 2006  hot, sunny

9:20 AM.  A lot of activity!  Approximately 15 martins present. When an SY-F with a yellow plastic color band appears, the males went nuts. She only stayed briefly.  The banded martins seen were:

yellow K384 ASY-M
yellow K501 SY-M
yellow P944 SY-M
yellow K566 SY-M
yellow T213 SY-M
yellow K493 SY-M
yellow E027 SY-M
yellow ???? SY-F (I think this was a plastic band, indicating she may have been from the Erie, PA area.  The bands used in southwestern PA are metal bands.)

There are tons of mayflies – so many that the lock workers have to sweep them up.  They are all over the buildings as well. (See photo below)



July 19, 2006

9:20 AM.  Again, tons of activity!  Nestlings are fledging. I saw:

yellow E027 SY-M
yellow T213 SY-M
yellow P944 SY-M
yellow K566 SY-M

July 20, 2006  Hot, high of 93F

In the AM, I saw the following banded martins, which include two birds never seen before:

yellow A597 SY-M  banded as a nestling in 2005 at the Shelocta colony, 22.5  miles WNW
yellow K262 ASY-F banded as a nestling in 2003 at the Saxonburg colony, 8.7 miles NNW (bred at Saxonburg in 2006)
yellow E027 SY-M
yellow K501 SY-M
yellow P944 SY-M
yellow K384 ASY-M

In the evening, I installed another T-14 in the yard area approximately 200 ft. north of the housing.  The red dot indicates the current location of the T-14’s, and the yellow dot indicates the location of the new T-14. The plan is to relocate the colony to this yellow dot area over the course of two years. One T-14 will be moved per year during the off-season. In other words, one of the two T-14’s at the current (red dot) location will be removed at the end of the 2006 season. This relocation will pose a challenge, which I will address in a future article. However, as I am erecting the new T-14, a group of 4-5 martins circles high above, calling – or perhaps scolding the decoys  – and I take this as a good omen. I put decoys on the roof and hang gourds under it. I also place mirrors in several entrance holes.

July 22, 2006  Saw yellow A597 SY-M, and yellow K501 SY-M

Natrona7Housing is located in red dot (south lawn) area in 2006. Both houses were moved to the yellow dot (north lawn) area by 2008. (See other article about “Effects of Moving Housing”)

July 23, 2006    Cool in the AM

I toss-fed eggs to the martins at the location of the new T-14 in the north yard. I have also moved the feeder to this location and put eggshell in it. Many martins took the tossed egg and fed it to their nestlings  and already-fledged young. There are 5 HY-U’s, along with several parents and SY-M’s perched in the dead treetop just downriver. I did a nestcheck:

WH-7      0 nestlings (all fledged)
WH-15    2 nestlings
WH-24    5 nestlings *

*One of the five is an already fledged martin from WH-7. It is sitting inside WH-24 in order to “steal” food being brought in by the parents of this nest. This behavior is known as kleptoparasitism.

July 24, 2006   I see martins on the new T-14 in the north yard.

July 25, 2006   8:00 PM – 9:00 PM  Many HY-U coming in like gangbusters.

July 26, 2006  Warm, sunny.  Tons of activity in the AM. Approximately 15 martins

7:30 AM – 10:15 AM.  Saw the following banded martins:

yellow E027 SY-M
yellow P944 SY-M
yellow K501 SY-M
yellow A597 SY-M
yellow K602 HY-U
yellow K613 HY-U

There were 9-10 martins hovering above and lading on the Trio Castle on the lock wall. Later in the day, I removed the Castle, since it has never been nested in by martins and I want them to focus on the T-14 in the new location.

8:00 PM – 8:30 PM.  The parents and fledglings are coming in for the night. I see

yellow K702 HY-U fledged from WH-7
yellow K707 HY-U fledged from WH-15

July 28, 2006 rain in the AM. 80’sF  Approximately 15 martins present.

9:30 AM  When I arrived, 7-8 martins hovered above me looking for eggs, so I went home and scrambled 8 eggs. I fed them in the north yard by the new T-14, and many ate and took it to their young. Among about 15 martins, I saw:

yellow K501 SY-M
yellow K493 SY-M
yellow T213 SY-M
yellow E027 SY-M
yellow A597 SY-M
yellow K384 ASY-M

July 29, 2006 

9:00- 10:00 AM: I saw the following banded martins among about 15 martins present:

yellow K527  SY-M
yellow K493  SY-M
yellow T213 SY-M
yellow E027 SY-M
yellow A5?? SY-M (blue anodized right)

They ate some egg, then all mysteriously disappeared around 10:00 AM.

July 30, 2006 

9:00 AM. No martins around. A few show up eventually and ate egg. A Cooper’s Hawk lands in the Elderberry tree next to the parking area. I run next to the tree and clap my hands and it flies off, low over the yards downriver, weaving among the houses. .

July 31, 2006 Hot, sunny

No martins around, but 8 show up when I lower T-14 #2  to do a nest check at mid-day. There is 1 dead nestling (or fledgling) with the band  yellow K715. I also saw:

yellow K384 ASY-M
yellow P944 SY-M
yellow T213 SY-M

August 2, 2006  Hot. 8:15 PM Approximately 10 martins came in, and all were inside by 8:45 PM.

August 3, 2006  Hot.

8:00 PM Counted about 14 martins, about half of which were HY-U. I also saw 2 unbanded HY-U. No ASY-M were observed.

August 10, 2006  7:45 PM  5-6 martins, 4 of which were HY-U. Saw yellow K713 HY-U. All went inside around 8:30 PM.

August 18, 2006  No martins came in tonight.



Banded Martins seen at the USACE Lock 4 Natrona, PA colony in 2006

yellow K384 ASY-M first seen 04/23/06; nesting in WH-15; banded as a nestling in 2004 at the Saxonburg colony, 8.7 miles NNW)

yellow A544 ASY-F only seen on 04/23/06;  banded as a nestling in 2004 at the Shelocta, PA colony, 22.5 miles WNW)

yellow K566 SY-M (first seen 05/29/06; non-breeder; banded as nestling in 2005 at the Natrona, PA colony)

yellow E027 SY-M (first seen 06/13/06; non-breeder; banded as a nestling in 2005 at the Shelocta, PA colony, 22.5 miles WNW)

yellow K501 SY-M (first seen 07/03/06; non-breeder; banded as a nestling in 2005 at the Saxonburg colony, 8.7 miles NNW)

yellow P944 SY-M (first seen 07/04/06; non-breeder; banded as a nestling in 2005 at the Zeglin’s Dairy Farm colony in Mt. Pleasant, PA, 32 miles SSE)

yellow K527 SY-M (first seen 07/08/06; non-breeder; banded as a nestling in 2005 at the Saxonburg colony, 8.7 miles NNW)

yellow K493 SY-M (first seen 07/10/06; non-breeder; banded as a nestling in 2005 at the Saxonburg colony, 8.7 miles NNW)

yellow A597 SY-M  (first seen 07/20/06; banded as a nestling in 2005 at the Shelocta colony, 22.5  miles WNW)

yellow K262 ASY-F (first seen 07/20/06; bred at Saxon colony in 2006; banded as a nestling in 2003 at the Saxonburg colony, 8.7 miles NNW)

yellow K602 HY-U (first seen 7/26/06; banded as a nestling in 2006 at the Saxonburg colony, 8.7 miles NNW)

yellow K613 HY-U (first seen 7/26/06; banded as a nestling in 2006 at the Saxonburg colony, 8.7 miles NNW)


Number of Purple Martins present at USACE Lock #4, Natrona, PA from April 23 – May 25, 2006.

April 23        2        ASY-M, ASY-F

April 25        1        ASY-M

April 28        1        ASY-M

April 29        1        ASY-M

April 30        1        ASY-M

May 02        2        2 ASY-M

May 03        1        ASY-M

May 04        1        ASY-M

May 05         2       ASY-M; ASY-F

May 06        2        ASY-M, ASY-F

May 09        3        2 ASY-M; ASY-F

May 10        3        2 ASY-M; ASY-F

May 11        5        2 ASY-M; 2 ASY-F; SY-M

May 12        4        2 ASY-M; ASY-F; SY-M

May 13        4        2 ASY-M; ASY-F; SY-M

May 14        4        2 ASY-M; ASY-F; SY-M

May 15        5        2 ASY-M; 2 ASY-F; SY-M

May 16        6        3 ASY-M; 2 ASY-F; SY-M

May 17        8        3 ASY-M; 2 ASY-F; 2 SY-M; 1 unknown

May 18        9        3 ASY-M; 2 ASY-F; 2 SY-M; 2 unknown

May 19        11

May 20        12

May 21        18 at 8:00 PM  (16 at 7:30 AM) ******* MOST EVER SEEN ***********

May 22        15

May 23        12 (approx.)

May 24        11

May 25        11 at 8:00 AM

Discussion-Analysis of Interesting Observations and Events

The male of the subadult pair that bred successfully in 2005 (yellow K404 SY-M) never returned to the Natrona site in 2006 (nor did he return to the Saxonburg site). Instead, the first returning male – who “anchored” the colony in 2006 – was only an infrequent visitor to the Natrona site in 2005. The female from the 2005 pair was unbanded, but an ASY female did nest in the same compartment that was used by the 2005 pair; there is no way to know if she was the same female. I am fairly certain, however, that K384’s mate was NOT last year’s female, because K384’s mate was very dark (atypical of a young adult female), and she chose to nest in the new T-14, rather than the one that was used last year. In the end, six pairs established themselves and laid eggs. I have always assumed that in order for a “one-pair colony” to survive, at least one of the parents needed to survive the off-season and return to the site. However, this assumption may be incorrect in light of the events of 2006. These developments seem to suggest that the survival and growth of a one or two pair colony is more dependent on the amount of activity that a site attracts in its first year than on the survival of the breeding parents. Keep in mind that at least 17 different martins were spotted at the Natrona site in 2005 – many on multiple occasions. Contradicting this notion, however, is the fact that none of the many banded martins that visited in 2005 returned to breed at the Natrona site in 2006.

None of the four most frequent visitors to the site in 2005, who collectively visited the site at least 32 times (probably many more) between June and August, returned to breed at the Natrona site in 2006. All four individuals returned to the Saxonburg colony and bred successfully there. They were yellow K279 ASY-M, yellow P524 ASY-M, yellow K415, ASY-M, and yellow K479 ASY-F. The last three martins were SY’s in 2005.  K279 and K479 were displaced breeders; K415 and P524 were non-breeding floaters. Despite experiencing total reproductive failure in at the Saxonburg colony in 2005,  K279 and K479 returned to breed there in 2006. Or doesn’t their experience qualify as TRF (total reproductive failure) since they never actually laid eggs at the Saxonburg colony in 2005? They only had their compartment blocked after pair-bonding and completing nests. Either way, the fact that they returned to breed at Saxonburg, a large, long-established colony, speaks to the powerful nature of site fidelity.

Yellow K384 was spotted at the Natrona site with a a banded adult female (yellow A544) on April 23, 2006, but that female left and K384 persisted in attempting to attract another female to the Natrona site for the next 12 days, until he succeeded in attracting the unbanded adult female that he eventually bred with. By leaving the Natrona site, was A544 rejecting K384 or was she rejecting the breeding site? Why didn’t K384 follow her to whatever site she may have chosen rather than continuing to attempt to lure a female to the Natrona site? Perhaps A544 was just investigating or staying over at the Natrona site. Perhaps K384 rejected the female? Why would this adult male who had never bred at this this site, persist so mightily in attempting to attract a female to it, especially when there were compartments available at a long-established and large colony 8.7 miles to the north (the Saxon Golf Course colony)

The first-arriving pair spent quite some time choosing a compartment to nest in. They slept and started partial nests in both WH-16 and WH-25, before finally laying eggs in WH-15.  I was playing dawnsong from a small speaker inside WH-28 and had a mirror positioned in the entrance of WH-27; did these stimuli influence the female’s behavior? It seemed as if she was often looking for the other “martins”. The dawnsong, decoys, and mirrors may have had a great deal to do with keeping this seemingly reluctant female interested in and eventually committed to the site. 30 days elapsed between the time of her arrival (May 5) until the laying of her first egg (June 4). Amazingly, an SY female, the third breeding female to arrive, laid an egg first (June 1), only 15 days after arriving on May 17 (or later). The 9-day period of poor weather from May 14 until May 23 may have been responsible.  Later arriving martins may have been in better breeding condition.

There were 18 martins present at the Natrona site on May 21, 2006, yet only one pair had bred there in 2005.  Why such a large number? The fact that I was offering emergency/supplemental feedings during a long period of poor weather was was probably the main factor. This may have been enhanced by the site’s strategic location on the Allegheny river. Rivers probably serve as migrational corridors for migrating birds, who use them both for navigation and as a food source. Insects tend to be most plentiful around water, especially during cool weather. The lower Allegheny river is actually more like a chain of  lakes, thanks to the series of dams that create large pools. And lakefront property is prime real estate for any swallows, especially martins. The cold-weather feeding and prime location probably combined to account for the growth in the colony from 1 to 6 pairs.

Only 1 of the 18 martins present on May 21 was banded, despite the fact that a very large percentage of nestlings at colonies within 30 miles of the Natrona colony have been banded for the past 4 years. How can this be explained? It seems reasonable to assume that many of these martins may have been from colonies further north along the Allegheny River area, or from unfed (and unknown) colonies nearby.

5 of the 6 breeding pairs (83.5%) nested in T-14 compartments; only 1 (16.5%) nested in a gourd.  The closest colony (Saxon Golf Course, 8.7 miles NNW) consists of two T-14’s – both with 100% occupancy for the past several years. But other than K384, none of the martins breeding at the Natrona colony in 2006 were banded, and all of the nestlings at the Saxon colony have been banded since 2002.