Category Archives: Birds of Prey

Hays Eaglets Growing Up

23 April 2021

The three youngsters in the Hays bald eagle nest have grown a lot in the weeks since they hatched on March 23 and 27. Their white natal down has been replaced by gray second down and they are showing pin feathers, the precursor to flight feathers and juvenile plumage.

On Wednesday 21 April they were glad to see food arrive. It was cold and there was snow on the nest.

You won’t see snow next Tuesday. Our high is forecast for 82 degrees F!

Watch the Hays eaglets grow on ASWP’s Hays Bald Eagle Nestcam.

p.s. This morning a squirrel is active below the nest while the adult eagles try to shoo it away. This squirrel probably doesn’t realize he could become lunch.

(photo and video from ASWP’s Hays Bald Eagle Nestcam)

Three Is Not a Crowd at Hays

Feeding time for 3 eaglets at the Hays bald eagle nest, 30 March 2021 (snapshot from ASWP’s Hays eaglecam)

31 March 2021

Yesterday was a great day to watch the three eaglets at the Hays bald eagle nest. It was warm and sunny so the nestlings were very active. The oldest (H13) even challenged his mother. “Feed me!” She gave him a stern look.

Today we’re in for all-day rain and falling temperatures to a low of just 24 degrees on Friday morning. At 6:30am today, rainwater beaded up on mother eagle’s back as she brooded them.

The eaglets are still so tiny that three is not a crowd — yet — at the Hays bald eagle nest. Watch them at ASWP’s Hays Bald Eagle Nestcam.

News from last Saturday 27 March: This year for the first time since 2014 all three eggs hatched at the Hays nest. The first two (H13 and H14) hatched 18 hours apart on 23 March. The last (H15) hatched on 27 March. In this snapshot from 3rd Hatch Day the oldest is four days old, the youngest is seven hours old.

Hays bald eagle nest on 3rd Hatch Day, Saturday 27 March 2021 (snapshot from ASWP’s Hays eaglecam)

(photos and video from ASWP’s Hays Bald Eagle Nestcam)

Osprey Back Yet?

Young osprey (photo by Dana Nesiti)

26 March 2021

There’s a Rule Of Thumb that says: Pittsburgh area osprey return from winter migration around St. Patrick’s Day.

This year the earliest eBird reports for southwestern Pennsylvania show osprey in Beaver and Butler Counties on 20 March 2021 and arriving this week along the Ohio River and at many lakes.

I haven’t seen an one yet so my goal this weekend will be to find an osprey, maybe at the Duquesne nest site.

My goal after that is to see an osprey do this …

(photo by Dana Nesiti)

Eagles and Peregrines Are On Different Schedules

First eaglet of 2021 in the Hays bald eagle nest, 23 March 2021 (photo from ASWP’s Bald Eagles of Western PA Facebook page)

23 March 2021

This week’s events at two Pittsburgh raptor nests show us that bald eagles and peregrine falcons are on different schedules during the breeding season.

At the Hays bald eagle nest the first eaglet of 2021 hatched early this morning. Audubon of Western PA announced that the eaglet broke out of his egg overnight and emerged at 3am, 23 March 2021. The “baby picture” above is from the ASWP Facebook page.

Meanwhile at the Cathedral of Learning peregrine nest, 3.5 miles away, Morela laid her third egg yesterday morning. Peregrines typically lay 3-5 eggs so Morela may lay more. We won’t know until we see it.

The peregrine timelapse video below shows the adults may be incubating, though I wonder about Morela’s 90 minutes on the perch from 4p – 5:30p. If incubating has begun the hatch date will be a month from now, approximately April 20-24.

Interestingly, though the peregrines started nesting a month later than the eagles they will more than catch up in the end. The Pitt peregrine nestlings will fly at least a week before the Hays eaglets.

The Hays eagles schedule this year is …

  • First eagle egg laid = 12 February 2021
  • First eagle egg hatched, first chick = 23 March 2021
  • First flight expected = guessing June 11 – 20

The Pitt peregrines’ schedule is …

  • First peregrine egg = 17 March 2021
  • First peregrine hatch (most will hatch on the same day) = approximately 20-25 April.
  • First flight expected = guessing 30 May to 4 June.

Soon the Hays bald eagle nest will have active fluffy chicks while the Pitt peregrines will embark on The Big Sit. For the next month it will be more interesting to watch the eagles than the peregrines.

Follow the Hays bald eagles at Bald Eagles in Western Pennsylvania – Audubon Society of Western PA on Facebook. Watch them live at ASWP: Hays Nest.

Watch the Cathedral of Learning peregrines at the National Aviary falconcam at Univ of Pittsburgh.

(photo of first Hays eaglet from ASWP Pittsburgh Eagles Facebook page, video from the National Aviary falconcam at Univ of Pittsburgh)

Nesting Underground

Burrowing owl in Florida (photo from Wikimedia Commons)

12 March 2021

Ah Spring! It’s time to nest.

Pennsylvania’s bald eagles are already on eggs in their huge stick-nests. Peregrine falcons are about to lay eggs on gravel ledges. Meanwhile, in Florida and southern California burrowing owls (Athene cunicularia) are preparing to nest underground.

Burrowing owls aren’t usually seen inside the nest because it’s dark in there. No problem. There’s plenty to see at the burrow entrance. Here’s a pair in Florida.

Happy Friday!

(photo from Wikimedia Commons, tweet from Wendy @geococcyxcal in southern California, video from photoguy73)

Great Horned Owls Don’t Always Win

Screenshot of great horned owl about to attack male bald eagle, 2 March 2021, 23:38 (from Pixcams video below)

5 March 2021

If you follow the Hays bald eagle family you know the female is incubating three eggs while her mate guards her overnight. The male has good cause to stay close. A great horned owl has been harassing them!

Almost two weeks ago, on Sunday 21 Feb 2021 at 9:26pm, a great horned owl knocked the male bald eagle off the “woods perch.”

Things seemed to calm down for a week. Then on the night of Tuesday 2 March 2021 the great horned owl came back twice.

The Hays bald eagles are probably feeling murderous about that owl right now so I’m sure they’ll like this trail cam video from Washington state in which a great horned owl is attacked by three species in a row!

Great horned owls may be everyone’s enemy but they don’t always win.

(screenshot from Pixcams video; click on the caption to see the original)

Evolve Quickly!

Snail kite with island apple snail, Harns Marsh FL, 2017 (photo from Wikimedia Commons)

Native from Florida to Argentina, the snail kite (Rostrhamus sociabilis) is a gregarious bird of prey that eats only one thing: freshwater snails in the genus Pomacea. Its beak is specially shaped to do so.

Snail kite, Florida 2019 (photo from Wikimedia Commons)

The Snail Kite’s slender, deeply hooked, sharp-tipped upper mandible permits it to cut the columellar muscle of Pomacea snails and remove soft tissues from the shells. The arc of the upper mandible approximates the inner spiral of the snail’s shell.

— paraphrased from Birds of the World, Snail kite account

In the old days before humans took over Florida’s landscape, snail kites ranged over half the state, but we drained and diverted more than 50% of Florida’s wetlands, the snail kite population crashed and was listed as Endangered in 1967. Twenty years ago, from 2000-2007, their population dipped so low that scientists feared they would go extinct in the U.S. Then a curious thing happened. Their food supply changed and the kites changed so they could eat it.

Before this century the snail kite’s main food was the native Florida apple snail (Pomacea paludosa) but an invasive species, the island apple snail (Pomacea maculata), arrived in 2000 and began to spread in Florida’s lakes and water management areas.

Island apple snails eating rushes (photo from Wikimedia Commons)

The island apple snail is two to five times larger than the Florida apple snail as seen below. (The white-and-gray bars are each 5 cm.)

Size comparison of Florida apple snail (P. paludosa) to Island apple snail (P. maculata). Each scale bar is 5 cm (images from Wikimedia Commons)

When the island apple snail first arrived in Florida the snail kite population dropped but less than a decade later the population began increasing. Did the birds initially have a tool problem? Were their beaks too short to get at the snail inside the larger shell? A recent study from the University of Florida indicates this was probably the case. Since 2007…

Researchers found that the birds with bigger bills were surviving, and their offspring were inheriting the bigger bills. …

“We found that beak size had a large amount of genetic variance and that more variance happened post-invasion of the island apple snail. This indicates that genetic variations may spur rapid evolution under environmental change,” Fletcher said.

— paraphrased from UF study: Bird evolves virtually overnight to keep up with invasive prey

We think of evolution as a very slow process but for the snail kite it happened quite fast. Those with longer bills survived. Nowadays they easily eat island apple snails.

Male snail kite with island apple snail, Florida, 2016 (photo from Wikimedia Commons)

When it’s a matter of life and death, evolve quickly!

Read more at the University of Florida study: Bird evolves virtually overnight to keep up with invasive prey.

(photos from Wikimedia Commons; click on the captions to see the originals)

Raccoon Redux

Bald eagle pair scares off raccoon approaching their nest, 17 Feb 2021 (screenshot from PixCams on YouTube)

19 February 2021

On Wednesday night, 17 February just after 7pm, a raccoon scaled one of the branches that holds the Hays bald eagle nest. The mother eagle was on the nest and heard the raccoon coming so she rose up, spread her wings, and scared him away.

Seven years ago a raccoon intruder did the same thing. This one was a little braver.

The raccoon hid nearby, frozen in place, but four minutes later he moved again and the father eagle arrived to help. Two eagles!! The raccoon finally left.

This week’s episode was a raccoon redux of …

See Mary Ann Thomas’ Trib Live report, Pittsburgh Hays Bald Eagles Attack Raccoon Intruder, with video of Wednesday’s raccoon leaving.

Watch the Hays Nest Eaglecam to see what happens next.

(screenshot from PixCams on YouTube)

UPDATE, 19 Feb 2021: The female bald eagle at Hays laid her 3rd egg on 19 February 2021.

UPDATE, 22 Feb 2021: On the night of 22 Feb 2021 a great horned owl knocked the male Hays bald eagle off his roosting perch. The eagle was surprised but unharmed.

Everyone’s Enemy

Great horned owl at Frick Park, April 2019 (photo by Steve Gosser)

16 February 2021

Most birds fear great horned owls (Bubo virginianus) for they are such top predators that they will eat the young of bald eagles, peregrine falcons and red-tailed hawks.

Their nesting habits are dangerous, too. Like other owls they never build a nest but great horned owls will steal one that looks good to them. They usually pick on red-tailed hawks. It leads to a fight as shown in the video below.

In early February 2019 a red-tailed hawk was building a nest at Presidio park in San Francisco when a great horned owl decided to steal it. The details of their encounter are quoted below the video. (Abbreviations: RTH=red-tailed hawk, GHO=great horned owl)

A pair of great horned owls have been visiting this red-tail hawk nest at the Presidio for several nights. This is the first time it’s come to the nest during the day, and the first time the RTH has seen it. It didn’t take kindly to the invasion and attacked it soon after it arrived. The GHO was able to fend off the RTH the first time, but in the 2nd attempt, it falls off the nest and doesn’t come back….until the next day. The RTH returns to make sure all is secure. Confrontations done in real time and SloMo. NOTE: The owl comes back the next day & lays an egg, and another a few days later. There are a few minor skirmishes, but the RTH finally moves on & lets the GHO have the nest. One of its two eggs broke, but the remaining egg is due to hatch mid-March. UPDATE: The 2nd egg failed to hatch also. The owl eventually moved on.

description of owl vs red-tail video on Janntonne’s channel on YouTube

If the owls are persistent, the red-tailed hawks eventually give up. Great horned owls outweigh red-tails by 30% and their talons are more than twice as powerful with a talon strength of 500 lbs per square inch. On the glove you can see the difference: red-tailed hawk (left), a great horned owl (right).

Here’s a comparison of their talons: red-tailed hawk on left, great horned owl on right (photos by Kate St. John at Medina Raptor Center, Ohio, Nov 2014)

Everyone’s enemy is a formidable foe. No nest is worth dying for.

p.s. It is likely that Pittsburgh’s great horned owls have already laid eggs — much earlier than bald eagles, red-tailed hawks and peregrines According to the Breeding Bird Atlas of Pennsylvania the earliest egg dates in PA are …

  • Great horned owl = 22 January
  • Bald eagle = 6 February
  • Red-tailed hawk = 24 February
  • Peregrine falcon in Pittsburgh = 6 March (based on falconcam at Pitt)

(owl photo by Steve Gosser, talon photos by Kate St. John)

UPDATE: On the night of 22 Feb 2021 a great horned owl knocked the male Hays bald eagle off his roosting perch. The eagle was surprised but unharmed.