Carla and Ecco have completed nearly two weeks of incubation at the Pitt peregrine nest and have three more to go. As we watch them on the National Aviary falconcam it can be difficult to tell who’s on camera because their appearance is similar. Here are some tips for figuring out which bird is on the nest right now.
Nighttime incubation? It’s Carla except …
Carla incubating at night, 27 March 2024, 10:58pm
Ecco sometimes brings food before dawn so you may see him on the nest in the early morning while Carla eats.
Ecco on the nest before dawn, 29 March 2024, 7:15am
Whenever you’re in doubt, use these tips.
Size: Carla is larger
Male peregrines are one-third smaller than females so size is the obvious way to tell the difference between the Pitt peregrines (see slideshow at top). However, Carla is not an enormous female and at close quarters on the falconcam with her back turned I have a hard time identifying her by size. The difference is obvious in this slideshow but not when Carla is alone on camera.
Plumage: Carla is Scalloped, Ecco is Striped
This spring in fresh breeding plumage Carla’s feathers have white tips that make her appearance look scalloped. Ecco’s feathers do not have long white tips so he looks vertically striped with fine black lines. Note that this difference works right now but feathers are dynamic and will not look the same in a few months.
Quiz! Test your skills
Practice recognizing size and plumage differences in this short video that compresses 60 hours into 1:41 minutes. At this speed the size differences between Carla and Ecco are obvious but you’ll have to look at one spot on the screen to notice plumage. Stare at one place and think “Scalloped or Striped?”
Incubation began last week at the Pitt peregrine nest. Carla and Ecco are now 6 or 7 days into The Big Sit.
To incubate their eggs and brood their chicks, birds open their warm feather coats by developing a brood patch for the breeding season. The brood patch is bare skin on their bellies that they place directly against the eggs to keep them warm. It has no feathers or down and lots of blood vessels close to the surface. When the bird is standing upright, surrounding feathers fall over the patch to cover it. If you had the bird in hand, as this bander holds a kestrel, blowing on the bird’s belly will move the surrounding feathers away so you can see the brood patch.
Both male and female peregrines have brood patches and both incubate the eggs. Instead of one big patch as on the kestrel, Birds of the World describes peregrines as: “Both sexes have paired lateral brood patches. Less well developed in male.”
To expose the brood patch and incubate the eggs, peregrines move the surrounding feathers out of the way by bobbing up-and-down and side-to-side. In this video Carla turns the eggs with her feet, then bobs to open her brood patch before she settles on the eggs.
Female peregrines incubate all night (with this interesting exception) but the amount of time the male incubates during the day depends on the couple’s preferences.
Some males love incubation duty, others not so much. Birds of the World sites several studies (paraphrased): “Based on studies in interior Alaska, males incubated about 33% of time. A study by Nelson suggested that for the Pacific Northwest male, incubation was 30–50% of the time. An extreme case in New Mexico was a male incubating as much as 87% of daylight period.”
Ecco loves to incubate so Carla and Ecco are still working it out. In this 20 March video Carla wails off camera “I want something to change!” Yup. She wants to incubate. Ecco eventually gets the message.
Peregrine eggs hatch 33-35 days after incubation begins but when did it start at the Cathedral of Learning?
Typically incubation starts after the next-to-last egg is laid — that would be Egg #3 on 19 March at 2am — but it looks like it may have begun on the 18th before that egg was laid.
Two Day-in-a-Minute videos illustrate the difference between incubating and not. This one on 17 March shows that the two eggs are often exposed.
Day-in-a-Minute, 17 March 2024
On 19 March there are 3 eggs and incubation has definitely begun. Notice that Ecco is on the nest more than half the time on that day –> 54%. He’s the smaller bird and is present 390 minutes out of 720 mins in the video. No wonder Carla wailed at him on the 20th!
Day-in-a-Minute, 19 March 2024
So incubation began on either the 18th or 19th of March. It is hard to tell about the 18th because it was cold that day (28°F to 36°F) and Carla and Ecco may have covered the eggs to protect them from freezing without opening their brood patches(*).
We’ll never know for sure whether the brood patch was open because we can’t see under the bird.
(*) EXPLAINING DELAYED INCUBATION: Some species, such as bald eagles, incubate immediately as soon as an egg is laid. Within these clutches the chicks hatch days apart from each other. Others species, such as peregrine falcons and ducks, want the clutch to hatch all at once so they delay incubation until the clutch is (nearly) complete. During freezing weather the eggs must be protected from freezing. Covering them without opening the brood patch is one way to regulate the start of incubation.
Carla laid her fourth egg at the Cathedral of Learning at 10:25a this morning, 56.4 hours after Egg#3. Most of us didn’t realize it happened. Thanks to Laurie Kotchey’s sharp eyes and her comment on my blog, I knew to start looking for Egg#4 when I got home at 11:30a.
The video below shows the egg-laying moment, sped up to double-time, but you won’t see the egg itself because Carla is facing the camera. Instead, watch her behavior. She eventually stands tall, opens her beak and points it upward. Wait for the moment when she bows down and raises her tail as she lays the egg.
Peregrine carrying prey at East Liberty Presbyterian Church, 8 Feb 2024 (photo by Malcolm Kurtz)
20 March 2024
Back in early February, Malcolm Kurtz stopped by East Liberty Presbyterian Church to photograph the resident peregrines. He found them carrying prey, perching on the steeple and hanging out together.
Malcolm first noticed the birds in December when “[he] saw an adult perched on the steeple from an overlook on Chatham’s main campus.” Good thing he followed up on it. The red aircraft hazard lights, which don’t look red from a distance, had fooled me so often that I stopped looking for raptors on the steeple. Malcolm’s photos show that a perched peregrine is about the same size as the lights but the bird is hard to see. If you’re near the steeple look carefully. How do peregrines manage to match every building they perch on?
Peregrine perched on East Liberty Presbyterian steeple, 8 Feb 2024 (photos by Malcolm Kurtz)
While on site on 8 February Malcolm saw the female (at right) bring prey back to the church and eat it while the male looked on (at left). Notice that she is peachy compared to him.
Peregrine pair at East Liberty Presbyterian Church, 8 Feb 2024 (photo by Malcolm Kurtz)
Meanwhile Adam Knoerzer checks on the peregrines every day and has noticed they’ve changed their area of focus. On 14 March he recorded the male flying in with prey and, later, the pair flying together.
Male peregrine brings food to the steeple, 14 March 2024 video by Adam Knoerzer
Pair of peregrines flying at E. Liberty Presby, 14 March 2024 video by Adam Knoerzer
The peregrines have been spending a lot more time on the east face of the steeple.
This is the side of the steeple facing Highland Avenue. Around a month ago, I primarily spotted them on the opposite side of the steeple and south face, but they have tended to perch over on this face in the past week or two.
— email from Adam Knoerzer, 14 March 2024
Green = floodlight where female likes to perch.
Red = plucking perch where male prepares food for female.
Blue = possible peregrine nest zone. Shows sticks leftover from old red-tailed hawk nest. Female often perches here at sundown. In first video below, male drops off food at this location.
Their change of venue probably reflects the lack of substrate anywhere else on the structure. This location is probably the only place that has an obstruction to prevent their eggs from rolling off the building.
If you want to see the East Liberty Presbyterian peregrines look from the Highland Avenue side first.
This morning Carla laid her third egg of the 2024 season at 2:01am. Because her nest is visible on a timestamped camera, I can tell you she laid the 3rd egg 52.87 hours after Egg#2. (Egg#2 was 53.14 hours after Egg#1.)
Here’s a video of the egg-laying moment, sped up to double-time, which happens to make it obvious.
video from the National Aviary falconcam at Univ of Pittsburgh
By 6:29am Carla had been off the eggs for 90 minutes (standing up). That’s a very long time to be off the eggs if she had already started incubation because they would cool dangerously in this morning’s freezing weather.
Carla off the 3 eggs for 90 mins, 19 March 2024, 6:29am (photo from the National Aviary snapshot camera at Univ of Pittsburgh)
Peregrine incubation begins when the female has laid her next-to-last egg but it is always hard to tell when it truly starts if the weather is cold because the adults cover the eggs to keep them from freezing. When incubation truly begins, the parent exposes the brood patch and lays its bare skin against the eggs. Peregrines can vary how much skin is exposed thus delaying the actual start of incubation until the clutch is nearly complete.
Carla laid her second egg last night at the Pitt peregrine nest, 16 March 2024 at 9:08pm.
In this video clip from the National Aviary falconcam we see the actual laying occurred quietly at timestamp 21:08:38. (This is 53.14 hours after her previous egg.)
Carla then raised her tail and remained in a standing position as she waited for the new egg to dry. Though the eggs are actually reddish in daylight, they look white under infrared night light.
Carla lays her second egg, 16 March 2024, 9:08pm (video from the National Aviary falconcam at Univ of Pittsburgh)
After the egg dried Carla roosted on the green perch in front of the nest.
Mother peregrines are the ones who stay at the nest overnight with eggs and chicks while their mates roost nearby. Ecco was apparently roosting within earshot but not very close. I believe he knew she had laid a second egg; he probably watched (off camera) when she laid it.
Carla was still asleep on the perch when it rained at 4:00am. When Ecco woke up at 4:30am he started to wail. Wailing means “I want something to change.” Perhaps Ecco wanted Carla to cover the eggs or maybe he meant, “I want to change places with you.”
Carla woke up and responded with unusual squeaky chirps. She jumped to the nestbox roof and Ecco arrived to cover the eggs. Listen for his voice and the sound of robins singing in the dark at the beginning of this video.
Overnight nest exchange at the Pitt peregrine nest, 17 March 2024, 4:35am
An overnight nest exchange is very unusual but I’ve seen it once before. When Dori was a new mother at the Gulf Tower in 2010, Louie took over incubation in the middle of the night a couple of times (*). Louie had experience raising a family and Dori did not. Perhaps he was getting the eggs through a critical period, waiting until he felt confident that Dori had caught on.
Peregrines are quick studies at being parents but it’s always nice when one of them already knows what’s going on, as Ecco does.
Note: Near the end of the video you will see white lines (not cracks) on the egg. DO NOT WORRY. THE EGG IS FINE.
Carla is a first-time mom so she moved the egg around a lot before it was dry. The reddish color is the last thing applied to the white eggshell before it is laid. While the egg is still wet the color can be smudged by the bird’s feathers or scratched by being moved on the gravel.
Peregrine falcon at opening to Third Ave nest, 10 March 2024 (photo by Kate St. John)
11 March 2024
Two weeks ago I issued the Southwestern PA Peregrine Challenge — Look for Peregrines in the Next 6 Weeks. The challenge won’t end in early/mid April but it will be a lot harder to find peregrines when they become secretive at their nests. We have 4 weeks before that happens. Meanwhile we have preliminary results. (See news after the map.)
The map below shows peregrine site observations in the past two weeks. The map has a …
Yellow checkmark = a pair was seen,
Yellow line = solo bird (We need to check again)
Yellow circle = NO ONE LOOKED HERE.
Notice the yellow circles. Ohio Valley birders, the challenge is on!
Don’t stop looking where you see a checkmark. There’s a spreadsheet at the end with site names and details.
Peregrine falcon pairs/nests in southwestern PA as of 10 Feb 2024 (map by Kate St. John)
Meanwhile, GOOD JOB!
Downtown Pittsburgh: (photo at top) Yesterday, 10 March 2024, I stopped by the Third Avenue nest site in Downtown Pittsburgh and found a peregrine at home.
Cathedral of Learning, Univ of Pittsburgh: Carla’s new behavior is a good sign. Last weekend she initiated courtship at the nest and Ecco brought her breakfast on camera. Watch the Pitt peregrines online at the National Aviary Falconcam at the University of Pittsburgh.
East Liberty Presbyterian Church, Pittsburgh: Many birders have confirmed the peregrine pair in East Liberty including videos from Adam Knoerzer at Pittsburgh Falconuts Facebook group and this ebird photo by Malcolm Kurtz. I visited on 4 March and found both birds on the steeple. Where and when will they nest?
62nd Street / Highland Park / Aspinwall Bridges (Allegheny County): No photos but on 8 March Justin Kolakowski reported at Six Mile Island, “Watched as a male and female pair chased off a Bald Eagle that was flying upriver, and then perched on the water tower.” (Six Mile Island is between the 62nd and Highland Park Bridges.)
Tarentum Bridge (Allegheny-Westmoreland County line): Dave Brooke, Meredith Cellitti, Dick Nugent and I have all visited the site in the past two weeks. On 7 March I confirmed incubation with the photo below. Hatch is expected in mid-April.
Female peregrine incubating at the Tarentum Bridge nest, 7 March 2024 (photo by Kate St. John)
Rt 422 Graff Bridge over the Allegheny River, Kittanning: Hooray for Dave Brooke! He found a peregrine here on 25 February.
Peregrine at the Graff Bridge, 25 Feb 2024 (photo by Dave Brooke)
Westinghouse Bridge: Hooray for Dana Nesiti who found both peregrines at home on 3 March.
Peregrine at Westinghouse Bridge, 3 March 2024 (photo by Dana Nesiti)Second peregrine at Westinghouse Bridge, 3 March 2024 (photo by Dana Nesiti)
Speers/Belle Vernon Bridge: Kudos again to Dana Nesiti for finding a peregrine at the Speers/Belle Vernon bridge on 25 February. This site had not been viewed since May 2023.
Peregrine at Speers/Belle Vernon Bridge, 25 February 2024 (photo by Dana Nesiti)
4 Weeks To Go!
There’s still time to look for peregrines before they get sneaky in early/mid April. Visit one or more of these sites and let me know what you see. Leave a comment with sightings or questions.
Egg laying season is coming up soon at the Cathedral of Learning peregrine nest where Ecco and Carla are courting frequently.
Yesterday they held three long courting sessions that included bowing, ee-chupping, and nest preparation. The ee-chup call sounds different for male and female peregrines. Ecco’s voice is squeaky while Carla’s voice is rough and slightly lower in pitch. She’s the one that makes the “huh” sound. You can hear the difference in this 6-minute video. More information on what they are up to is described below.
To “build” the nest, Carla put her chest against one edge of it and kicked the gravel out with her feet. The nest itself is a bowl in the gravel, called a scrape, for holding eggs so they don’t roll off the cliff. Peregrines don’t use sticks to build their nests.
After digging Carla puttered around on the gravel surface, swallowing small pieces of gravel to aid digestion. Birds add gravel to their gizzards to grind the food. Learn more about How Birds Chew at the link.
Peregrine pair at Tarentum Bridge, 19 Feb 2024 (photo by Dave Brooke)
25 February 2024
From now until the middle of April peregrine falcons in southwestern Pennsylvania are courting and claiming territory, perching prominently, and performing conspicuous aerial displays. As soon as they start incubating eggs they’ll become very secretive so if you want to see a peregrine or record breeding activity for the new Breeding Bird Atlas 2024-2029, this is a great time to do it.
Look for peregrines in the next 6 weeks.
The red and blue pin drops, 1 Dec 2023 — 24 Feb 2024, on the eBird map below confirm that the best places to look are near tall buildings or bridges. There are also a few surprising locations such as Mammoth Lake Park in Westmoreland County.
11 peregrine territories have pairs present since January. Here’s the simpler map.
Peregrine falcon pairs in southwestern PA as of 25 Feb 2024 (map by Kate St. John)
Of those 11 sites, five raised young last year and two more have a long history of nesting (7 boldface names below). The new and promising sites are boldface in the Notes column.
Peregrine Sites to Watch!
Looking for some excitement? Want to add Peregrine Falcon to the PA Breeding Bird Atlas? Check out these “hopefuls” for 2024.
Rt. 40 Bridge in West Brownsville, PA (Washington County). New nest (to us) last year, will they use it this year? Click here to read about this nest.
Female peregrine clutching prey and shouting, West Brownsville Lane Bane Bridge, 26 May 2023 (photo by Jeff Cieslak)
Location of peregrine focus (potential nest site) at East Liberty Presbyterian Church, 12 Feb 2024 (photo by Adam Knoerzer)
West End Bridge over the Ohio River, Pittsburgh. This site often has pairs but no indication of nesting … yet. Click here to read all about it.
Sewickley Bridge over the Ohio River. This site also has pairs but no confirmation of nesting yet.
Peregrine at Sewickley Bridge 11 March 2023 (photo by Jeff Cieslak)
Monaca bridges over the Ohio River: RR Bridge or Rt51 Bridge. We know there are peregrines here but it’s hard to confirm breeding. Let this be a challenge to you!
Peregrine at Monaca RR Bridge, 9 Jan 2023 (photo by Jeff Cieslak)
Rt 422 Graff Bridge over the Allegheny River, Kittanning. We know there are peregrines here too, but with few observers we often don’t confirm breeding. Allegheny Valley People, let this be a challenge to you!
And … if you miss finding a peregrine in person you can usually count on a peregrine on camera at the Cathedral of Learning. Today they courted at dawn.
