Category Archives: Bird Behavior

Young Peregrines As Home Wreckers

Young intruder female challenges Trailblazer at CVNP/I-80 nest site, 5 March 2023 (photo by Chad+Chris Saladin)

9 April 2023

After reporting on the peregrine drama last Wednesday in Downtown Pittsburgh I went there on Thursday 6 April to investigate. There were no peregrines at Gulf Tower but in just 15 minutes of watching at Third Avenue I saw two peregrines and a possible nest exchange. The departing bird was normal adult color (gray & white) and did a territorial flappy flight as it left. The arriving bird was very dark chocolate brown like the bird in Ann Hohn’s photo on 3 April.

Dark plumage peregrine at the Gulf Tower, approx 3 April 2023 (photo by Ann Hohn)

If this pair is on eggs, the arriving bird’s behavior did not match an incubating female. Instead of quietly moving to the nest the arriving bird called loudly for several minutes. It sounded like “Hey, come back!”

When I mentioned this on Pittsburgh Falconuts Facebook page, Jeff Cieslak remarked: “I’d say that’s pretty good news. But it does raise some questions, neither of the birds I saw on 3/3 were brown.” Here’s the peregrine pair Jeff photographed a month ago.

Female at Third Ave nest Downtown 3 Mar 2023 (photo by Jeff Cieslak)
Male peregrine at Third Ave Downtown, 3 Mar 2023 (photo by Jeff Cieslak)

Correction as of early June 2023: The dark bird is not immature, just dark, and is the mother bird at Third Avenue. … The Theory below is based on incorrect information.

Aha! So the immature bird is an intruder. The quick exit of the adult bird Downtown is like Terzo’s reaction in 2016 when female intruders visited the Cathedral of Learning. Terzo always left quickly and the intruder female always remained at the nest. Adult females were silent but an immature female called loudly. (See this vintage article: Juvenile Female Intruder at Pitt on 8 April 2016.)

Why didn’t the Downtown adult peregrines attack? Peregrine falcon literature says that immature plumage protects young birds from attacks by territorial adults because they aren’t perceived as a threat. Young peregrines won’t breed until they have adult plumage at two years old(*).

… end of bad theory …

In this attack at CVNP/I-80, photographed by Chad+Chris Saladin, Chris explains that the adult male is not brutal to the one-year-old, partly because she’s female and partly because she’s immature.

Young intruder female challenges Trailblazer at CVNP/I-80 nest site, 5 March 2023 (photo by Chad+Chris Saladin)

Yet these one year-old peregrines are disrupting nests. Are they trying to claim territory? Are they thinking about nesting?

Sara Showers reminded me of an article I wrote in 2020: “A year or two ago, it was pointed out to me that one of the factors that causes falcon populations to plateau at the “carrying capacity” isn’t just a finite food supply. When populations are very high, constant competition over nesting sites can cause those contested sites to not produce chicks in a given year – restricting population growth.”

Read about the Home Wrecker phenomenon in this 2020 article, written when Ecco was the young “intruder” and nesting failed that year.

(*) A note from Chris Saladin: “We’ve had 2 females successfully breed when they were just 1 year old, though it certainly isn’t common.”

(blue sky fight photos by Chad+Chris Saladin, adult peregrines at Third Ave by Jeff Cieslak, immature peregrine at Gulf Tower Ann Hohn)

Two Tail-Waggers Are Back in Town

Eastern phoebe, Carondelet Park, 26 March 2017 (photo by Andy Reago & Chrissy McClarren via Wikimedia Commons)

3 April 2023

On Saturday before the storms I saw my First Of Year eastern phoebes (Sayornis phoebe) in Schenley Park while Kathy Saunders found a first Louisiana waterthrush (Parkesia motacilla) at Tom’s Run Nature Reserve. Two tail-waggers are back in town.

Few birds wag their tails side to side but we do call it “wagging” when they bob or pump their tails up and down. Eastern phoebes are subtle about it but the movement is almost constant and it draws our attention.

Video by GoTrails on YouTube

What makes phoebes wag their tails faster? Predators! Sibley describes a 2011 study of black phoebes:

Avellis concludes that tail pumping is a signal meant to send a message to the predator. It tells the predator that the phoebe has seen it, and therefore the phoebe is not worth pursuing.

Sibley Guides: Why Do Phoebes Pump Their Tails?

Louisiana waterthrushes don’t just wag their tails. They continuously bob the entire back end of their bodies by moving their ankle joints. Birds’ ankles are the backward “knees,” the middle joint on their legs, hidden by this waterthrush while he dips his butt.

Louisiana waterthrush, April 2020 (photo by Steve Gosser)

His bobbing is like a habit he just can’t quit.

video by Jim Zipp @mcelroyproductions76 on YouTube

Louisiana waterthrushes have a different reason for tail wagging than eastern phoebes and they hold their technique in common with another April migrant, spotted sandpipers.

In case you missed it, here’s why they “wag” their tails.

(photo and video credits are in the captions)

To Lek or Not to Lek: Grackles Lead Different Lives

Male common grackle, puff and “skrinnk” (photo by Norm Townsend via Flickr Creative Commons license)

23 March 2023

Lek: an assembly area where animals (such as the prairie chicken) carry on display and courtship behavior. Also an aggregation of animals assembled on a lek for courtship.

Merriam-Webster Dictionary

Male prairie chickens hold a lek to attract females and according to this diagram so do “grackles.” It was exciting to think that the puff and “skrinnk” of male common grackles in Pittsburgh was a lek. But it’s not! The three species of grackles in North America lead very different lives.

Common grackles (Quiscalus quiscula), are usually monogamous and may nest alone or colonially with up to 200 pairs in a single colony.

Common grackles, Bill Up Display (photo by Tony Morris via Flickr Creative Commons license)

Bill Up is a male-to-male threat display. The puff and skrinnk is Song during courtship.

Boat-tailed grackles (Quiscalus major), found in Florida and along the Atlantic and Gulf coasts, nest in harems. The males gather in leks to attract the females.

Boat-tailed grackles perform during the breeding season (photo by shell game via Flickr Creative Commons license)
Male boat-tailed grackles on the lek (photo by Judy Gallagher on Flickr via Creative Commons license)

Female boat-tailed grackles are dull brown and laid back compared their male counterparts.

Female boat-tailed grackle (photo by Melissa McMaster via Flickr Creative Commons licnse)

Great-tailed grackles (Quiscalus mexicanus), found west of the Mississippi and in Central America, gather in noisy winter flocks.

Great-tailed grackle flock (photo by Phillip Cowan via Flickr Creative Commons license)

In the breeding season they don’t use leks and they aren’t monogamous.

Great-tailed grackle (photo by designwallah via Flickr Creative Commons license)

Birds of the World explains:

[Their] mating system can be described as non-faithful female frank polygyny, in which a territorial male has one or more social mates, each female has one social mate, and both sexes employ extra-pair copulation as a conditional mating tactic. Territorial males defend a small territory including from 1 to several trees, where one or more females nest. The male protects nestlings hatched on his territory, but not nestlings from other territories. He copulates with his social mates and may attempt to copulate with other females. 

Birds of the World: Great-tailed grackle account

Frankly, all the great-tailed grackles mess around. Even the females swagger.

Female great-tailed grackle (photo by Charlie Jackson via Flickr Creative Commons license)

Though they’re all called “grackles” they don’t act the same.

(photos are Flickr Creative Commons licensed and credited in the captions, click on the captions to see the originals)

Preparing To Set Up His Harem

Male red-winged blackbird (photo from Wikimedia Commons)

15 March 2023

The guys are back in town! Male red-winged blackbirds returned to western Pennsylvania early this month to get a jump on the breeding season. Males arrive 2-4 weeks before the females in order to shake down who owns what territory before the ladies get here.

Male red-winged blackbird claiming territory (photo from Wikimedia Commons)

The best territories are in the middle of a marsh and claiming a good one is extremely important. When the females arrive they chose a mate based in part on the quality of his territory. If the male and his territory are exceptional, up to 15 females join his harem.

Female red-winged blackbird with nesting material (photo fro Wikimedia Commons)

According to Birds of the World, experiments have shown that females prefer a harem on good territory to being the lone mate of a male on poor territory. Female red-winged blackbirds would rather be one of many wives than alone with one male in a lousy home. With that in mind the males are getting ready to set up their harems.

Watch for the arrival of female red-winged blackbirds in late March or early April. You’ll hear the boisterous clamor of males when they see the flocks of females.

This 3-minute video shows red-winged blackbird behavior in the spring.

video from Cornell Lab of Ornithology on YouTube

(photo from Wikimedia Commons, video from Cornell Lab of Ornithology on YouTube; click on the captions to see the originals)

Report “Tame” Ruffed Grouse for This Study

“Tame” ruffed grouse at Moraine State Park, 13 Nov 2020 (photo by Dave Brooke)

13 March 2023

In November 2020 the ruffed grouse pictured above caused a sensation among birders by coming very close to us at Moraine State Park. He even chased my car!

The “tame” ruffed grouse looks at me, Moraine State Park, 13 Nov 2020 (photo by Kate St. John taken on my cellphone)

“Tame” ruffed grouse (Bonasa umbellus) are not common in Pennsylvania but where they occur they are quite noticeable. They aren’t afraid of humans and they sometimes act aggressively. Why do they do this?

This spring the PA Game Commission, in cooperation with Penn State, is conducting a ruffed grouse genetics study to find out. They are asking the public’s help to locate “tame” grouse for the study.

The Game Commission is encouraging Pennsylvanians to report the location of any “tame” grouse they see this spring by sending an email to That email should include the person’s name and phone number, date of the sighting, location of the encounter and a description of the grouse’s behavior. Ideally, those sending in a report should also include GPS coordinates for the encounter site.

PGC Press Release: Public asked to report “tame” Grouse Sightings

According to the press release, “The study aims to determine whether the Commonwealth’s grouse population shows signs of splitting up into distinct subpopulations and if “tame” behavior is linked to genetics.”

If you know of a tame grouse in PA please report it.

Meanwhile here’s a video that shows the “tame” grouse behavior.

(photos by Dave Brooke and Kate St. John, video from PA Game Commission on YouTube)

He Doesn’t Just Stand Around

Reddish egret, Marco Island, FL (photo from Wikimedia Commons)

10 March 2023

Egrets and herons are known for standing completely still and waiting for a fish or frog to swim toward them until they stab and grab it from the water.

Reddish egrets (Egretta rufescens) seem manic by comparison, “dancing” so much that they look crazy. Their hunting techniques include:

  • Foot wiggle
  • Umbrella wings
  • Stab the water
  • Prance and dance
  • Hover-fly with dragging legs

Watch for these antics below.

This immature bird’s umbrella wings look like a victory pose:

There is one notable moment when a reddish egret will stand around. According to Birds of the World, during Pair Formation in the breeding season (April) the “Male takes up position atop mangrove canopy or on low-growing vegetation and “stands around” in Upright Display position.” He’s waiting to win a mate.

If you want to see a reddish egret visit a coast highlighted on the map below. This bird only fishes in shallow saltwater.

Range map of reddish egret from Wikimedia Commons

Despite its large range the reddish egret occupies a restricted habitat and is patchily distributed. It is listed as Near Threatened.

(photo and map from Wikimedia Commons, videos embedded from American Bird Conservancy and @wideangl on YouTube, tweet embedded from Twitter)

Bow and Sashay at the Nest

3 March 2023

This morning we may be two weeks away from the first Pitt peregrine egg of 2023. Morela’s first egg in 2021 was March 17, last year it was March 18. But who knows? She could be early or late this year.

Yesterday the pair had three bowing sessions at the nest. The first was brief and initiated by Ecco. The second was longer and Morela stuck around to dig the scrape. The third was unusual: Morela spent the entire time on the nestbox roof while Ecco bowed below. Did you see her yell at him from the roof? Check out this photo.

When the pair is not together one of them may be on the green perch, stepping in a sideways sashay. (This sashay video repeats the steps for emphasis.)

While you watch the falconcam get some practice identifying the birds with the two-photo slideshow at top. Notice that Ecco is small, has brighter-white and darker-gray feathers (more contrast), and has bright orange skin on this face and legs. Morela’s feathers are duller with less contrast, she’s bigger, and she has a peachy chest.

Click here and scroll down to watch the National Aviary Falconcam at the Cathedral of Learning. The Birdwatchers Store in Slippery Rock, PA is sponsoring the falconcam!

(photos and video from the National Aviary falconcam at Univ of Pittsburgh)

Pigeons Clap In Courtship

Rock pigeon in flight (photo from Wikimedia Commons)

2 March 2023

It’s spring and our local pigeons (Columba livia) are prancing in courtship. The males bow and coo to their chosen mates and accompany their ladies in flight. When their courtship is successful the males clap their wings.

You can hear cooing and wing clapping in this audio clip …

… and see it as they fly in this video.

video from @MrMattperry on YouTube

Learn their courtship moves in this vintage article. Keep track of the pairs you see on the pavement. Pigeons mate for life!

(photo from Wikimedia Commons, video from @MrMattperry on YouTube, click on the captions to see the original)

Blue Jays Eat Acorns

Blue jay carrying acorns, September 2022 (photo by Christopher T)

9 February 2023

Nuts seem an unlikely food for blue jays but in fact they make up 67% of their diet in winter. Acorns are their favorites but they also eat beechnuts, chestnuts, hickory nuts and hazelnuts depending on availability.

Jays pluck acorns from the trees in autumn and eat them on site or cache them for later consumption. You would think acorns are too hard for a blue jay to open but Birds of the World (Cyanocitta cristata) explains how they do it:

Hard foods such as acorns, dry dog food, eggs, etc., are rendered by holding them against a branch or other substrate with one (usually) or both feet, and hammering with the mandible. 

Blue jay hammering at food (photo from Wikimedia Commons)

To cache the nuts — as much as 2.5 miles away — blue jays stuff their faces. The blue jay at top is carrying two acorns in his throat and one in his beak. The blue jay below is going overboard with peanuts. When they reach their cache sites they dump the nuts in a pile and bury them individually.

Blue jay stuffing his throat to carry away some peanuts (photo from Wikimedia Commons)

Blue jays have a great memory for where they’ve buried nuts but they stash so many that they inevitably lose track of a few.

“Is that were I buried an acorn last autumn?” (photo from Wikimedia Commons)

If they don’t retrieve all of them, no problem. The acorns germinate and become new trees. Studies have shown that “This tendency may account for the rapid post-glacial dispersal of oaks indicated by pollen analysis,” according to Birds of the World. With this in mind, the Agassiz Audubon Society in Minnesota enlisted the help of blue jays ten years ago to “plant” oaks after volunteers collected and dispersed thousands of native acorns in an area that needed new trees.

To retrieve their cached food, blue jays dig it up with their beaks but this doesn’t work when the ground is frozen. It’s just one more reason why blue jays migrate south for the winter.

If your neighborhood doesn’t have any blue jays right now, it may be because they migrated. But check out the local trees. If there aren’t any oaks or nut trees in your neighborhood that may explain why you haven’t seen any blue jays lately.

This vintage article still gets a lot of comments because people miss seeing blue jays.

(top photo by Christopher T via Flickr used by permission. Remaining photos from Wikimedia Commons; click on the captions to see the originals)

A Bird Pierced This Flower

Evidence of flowerpiercer on a passionflower (Passiflora sp.), Yanacocha, 30 Jan 2023 (photo by Kate St. John)

11 February 2023

On our first day in Ecuador, 30 Jan 2023, we traveled to Yanacocha Biological Reserve 11,500 feet up on the Pichincha Volcano. We were wowed by the huge passionflowers (Passiflora sp.) dangling from vines along the trail but on close examination found a hole in this flower tube. It was made by a bird.

Passionflowers hanging from the vine, Yanacocha, 30 Jan 2023 (photo by Kate St. John)
The face of the same passionflower pictured at top, Yanacocha, 30 Jan 2023 (photo by Kate St. John)

These passionflowers evolved long tubes in an arms race against hummingbirds who developed ever-longer beaks to reach the nectar. However members of the Tanager family eat nectar, too, even though that have short beaks and cannot hover at the flower opening. Flowerpiercers (Diglossa sp.) land on the flower and bypass the flower’s defenses by poking a hole in the tube.

Masked flowerpiercer, Yanacocha, 30 Jan 2023 (photo by Mary Eyman)

Masked flowerpiercers (Diglossa cyanea) and glossy flowerpiercers (Diglossa lafresnayii) were abundant at Yanacocha. We could hear them chattering in the forest …

… and see them at the nectar dishes. (The glossy flowerpiercer is black with a white shoulder at left below.)

Glossy (black at left) and masked flowerpiercers (blue), Yanacocha, 30 Jan 2023 (photo by Kate St. John)

Flowerpiercers are specially equipped for piercing flowers with a hook at the tip of their beaks. This photo from Wikimedia Commons shows the hooked tip.

Masked flowerpiercer at Yanacocha, 2007 (photo from Wikimedia Commons)

In Pennsylvania it’s the hummingbirds that eat nectar and insects that make holes in flowers. It’s amazing to think there is so much nectar in Ecuador that birds bother to pierce the flowers.

(photos by Kate St. John, Mary Eyman and Wikimedia Commons)