Category Archives: Birds of Prey

This Can’t Be Good for Our Eagles

Birds of Prey, Musings & News, Water and Shore
Bald eagle with nestling, 23 March 2019 (screenshot from Bald Eagles in Western PA – Audubon Facebook page)

26 November 2024

On 14 November The Allegheny Front described oil pollution on the Monongahela River that’s been happening for more than two years. Monitored by Three Rivers Waterkeeper since May 2022, an oil sheen sometimes covers the water from bank to bank for three miles, all the way to McKeesport. This can’t be good for our bald eagles who nest along on the Mon and eat fish from its water.

In October 2023 Three Rivers Waterkeeper posted photos of the oil sheen on Instagram.

“These are pretty serious sheens,” said Captain Evan Clark, a boat captain for Three Rivers Waterkeeper. “When I’m boating around up there, my boat is running through a heavy rainbow sheen that can extend from one bank of the river to the other, literally for miles.”

In August 2022, an EPA inspector reported oil discharge from the plant’s outfall, or drainage pipe, and found “substantial rainbow sheening could be seen for approximately 3 miles downstream.”(*)

— The Allegheny FRONT: Group wants stricter permit for U.S. Steel to stop oily releases into Mon River

Last year the Pennsylvania Dept of Environmental Protection (DEP) determined the oil was coming from a USS Irvin Works outfall and “issued a compliance order requiring U.S. Steel to deploy absorbent booms, investigate the cause of the releases and implement a plan to fix any problems.” — The Allegheny Front 

But a year later the problem has not been addressed and it happened again last month. DEP has proposed setting a water pollution permit level on that outfall. Three Rivers Waterkeeper wants real-time monitoring on it.

Meanwhile, oil-covered water cannot be good for our bald eagles who touch the water’s surface and eat fish and waterfowl captured in or on the water.

Bald eagle about to catch a fish (photo from Wikimedia Commons)

During an oil sheen episode the pair that nests at USS Irvin Works cannot hunt the Mon for three miles downstream of their nest without being exposed to the oil. This is a lot of territory to avoid with hungry chicks in the nest.

screenshot from USS Irvin Works Eaglecam via PixCams on YouTube, 5 April 2022

Employees at USS Irvin Works are so proud of their bald eagle pair that the company installed an eaglecam to watch them at the nest. Surely USS Irvin Works will clean up this outfall to protect everyone who uses the Mon including their favorite eagles.

Read more about the issue here at The Allegheny Front …

Group wants stricter permit for U.S. Steel to stop oily releases into Mon River

… and WTAE’s 26 November report: Mon River oil sheens: Environmentalists urge stricter enforcement on US Steel.

Seen This Week: Witch-Hazel, Whoosh and Brown Leaves

Birds of Prey, Phenology, Plants & Fungi
Witch hazel, Schenley Park, 15 Nov 2024 (photo by Kate St. John)

16 November 2024

This week I found witch-hazel (Hamamelis virginiana) blooming in Schenley Park and was startled by a whoosh of wings that passed right in front of me below eye level. I was so startled that I screamed even though I knew that …

The whoosh was an immature red-tailed hawk zipping by to catch a mouse near the wall. In stealth mode the hawk did not flap his wings but he flew pretty close to me. If I didn’t like birds I might have been freaked out. He caught the mouse and I took his picture when he settled down.

Immature red-tailed hawk that buzzed past me in Schenley Park, 15 Nov 2024 (photo by Kate St. John)

By now most oaks have lost their leaves so the predominant color in Schenley and Frick is brown. Brown on the ground and lots of bare trees.

Brown fallen leaves, Schenley Park, 15 Nov 2024 (photo by Kate St. John)

In Schenley Park you can easily see through the woods at ground level because the deer have eaten all the thickets.

In Frick Park I spotted an unusual patch of green, probably an alien plant, so I went down there to check it out.

A green patch in the distance at Frick Park. What is it? 12 Nov 2024 (photo by Kate St. John)

Sure enough, this is an alien — stinging nettle (Urtica dioica), native to Eurasia and Africa. Deer eat stinging nettle in spring and summer but are shunning it at this time of year.

A patch of stinging nettle in Frick Park, 12 Nov 2024 (photo by Kate St. John)

By now the only place to find brilliant reds is in the sky.

Sunrise in Pittsburgh, 10 Nov 2024 (photo by Kate St. John)

Merlin versus Crow: How to Win a Nest

Bird Behavior, Birds of Prey, Crows & Ravens
Merlin, eastern US (photo by Wm.H. Majoros via Wikimedia Commons)
Merlin, eastern US (photo by Wm.H. Majoros via Wikimedia Commons)

29 October 2024

Last spring during the nesting season I was so distracted by peregrines that I neglected to check on a merlins’ nest reported in Highland Park. By the time I got over there the young had fledged, the merlins were gone, and a small group of American crows were inspecting the area and commenting on what they found.

Crows are intensely interested in merlin nests because those nests may have been stolen from crows.

Merlins (Falco columbarius) never build a nest. Instead they search for crow or hawk nests, ideally in conifers, and take them over. If the target nest is unoccupied no problem but merlins are feisty and will try for an active crows’ nest by driving off the incubating female crow. If harassing her doesn’t work, they shout at her all day until another predator shows up and forces her to leave.

This often works because merlins are loud and fearless. They’ll drive away anything that irritates them including this raven (a merlin predator not a competitor).

Merlin attack! Raven flips upside down, Renews, NL, 10 July 2010 (photo by Trina Anderson)
Merlin attack! Raven flips upside down, Renews, NL, 10 July 2010 (photo by Trina Anderson)

However, in southwestern Pennsylvania there are now two species of crows — American crows (Corvus brachyrhynchos) and fish crows (Corvus ossifragus) — and it makes a difference to the merlins’ success.

American crow and fish crow (photos from Wikimedia Commons)

A 2019 study presented at the Wilson Ornithological Society showed that if the merlin nest was successful, chances are the nest had been owned by American crows.

Merlin chicks in nest (photo from Wikimedia Commons)

Behavioral interactions between nest-parasitic Merlins (Falco columbarius) and nest-building Fish Crows (Corvus ossifragus) in a new zone of overlap explains that American crows and merlins have coexisted for millennia so they have forged a working relationship and can reach detente early on. One or the other cuts their losses and nests elsewhere.

Not so with fish crows. Merlins and fish crows are new to each other so they haven’t worked out their differences and continue harassing for a much longer period. Few or none on either side have a successful nest. In the study of 25 fish crow nests in upstate New York, 40% failed due to merlin interference. The study tracked 31 merlin nests and found 66% of those made in fish crow nests did not fledge young.

Autumn and winter are good times for seeing merlins and fish crows in Pittsburgh. It would be interesting to find them interacting in spring and watch what happens.

p.s. Thank you to Don Nixon of PA Merlins for alerting me to this fascinating topic. The paper(*) is by Connor O’H. Loomis and Anne B. Clark (Binghamton University), John Confer (Ithaca College), Kevin J. McGowan (Cornell Lab of Ornithology) but it is behind a pay wall. The fish crow and merlin nesting studies continue beyond 2019 in Ithaca, NY at Cornell Lab of Ornithology.

To See or Not To See Ultraviolet Light

Bird Anatomy, Birds of Prey, Songbirds
Female European starling, Golden eagle (photos from Wikimedia Commons)

13 August 2024

Just because an animal has UV receptors in its eyes does not mean it can see ultraviolet light. A recent BBC video, below, reveals some surprising things about the use and perception of ultraviolet light in starlings (Sturnus vulgaris) and raptors, especially golden eagles (Aquila chrysaetos). For instance:

  • Starlings and golden eagles both have UV receptors in their eyes.
  • Female starlings have feathers that reflect UV. The more UV a female reflects the more successful she is at breeding. Male starlings like the glow we humans cannot see.
  • UV light scatters more. If you can see UV light, it makes images blurry.
  • Raptors have UV receptors in their eyes but they cannot see it because their lenses filter it out. The golden eagle’s vision is sharper because he cannot see UV.
  • Scientists used to think kestrels hunted by seeing the UV reflective paths of rodent urine. Nope. Kestrel eyes filter out UV so that theory has been disproved.

Interesting conclusions:

  • Because I thought that raptors could see UV, I used to wonder how flashy UV-reflective songbirds managed to evade predators. Answer, the predators cannot see that flashy stuff!
  • UV light damages the eye so there is an advantage to not seeing it for most of one’s life.
  • Human eyes have UV receptors but we cannot see it because our lens filters out UV. There are exceptions based on age and lack of lenses.
    • Exception#1: Young people up to age 30 can see near UV, the wavelengths closest to our visible color range, per a 2018 Univ of Georgia study.
    • Exception#2: Those without lenses in their eyes can see near UV. This includes those born without lenses and those who had cataract surgery in the early days. Claude Monet had cataract surgery in 1923 with no lens replacement and could see near UV.

Read more about human perception of UV light in this Live Science article: Can Humans See Ultraviolet Light?

American Kestrels Ready to Fledge

Birds of Prey, Nesting & Courtship
Screenshot from the Live Kestrelcam at CornellBirdCams

17 June 2024

Are you going through Falconcam withdrawal? Don’t despair. Four falcons in Wisconsin are still on camera and nearly ready to fledge.

Click on the image above or this link at Instagram for a brief video of American kestrel nestlings (Falco sparverius), the smallest falcon in North America.

See them Live on the Wisconsin Kestrel Cam below … WOW! That was fast! All of them fledged within a day of this article and the Live Stream is closed for the year. The kestrels say, “See you next year!”

Seen This Week: Flowers and Owls

Birds of Prey, Phenology, Plants & Fungi
Saucer magnolia bud about to bloom, Pittsburgh, 18 March 2024 (photo by Kate St. John)

23 March 2024

This week non-native flowering trees put on a show in the city of Pittsburgh. Originally from China and Japan their growing season is earlier than our native trees.

Star magnolia in bloom, Pittsburgh, 15 March 2024 (photo by Kate St. John)

This month’s three-day spurts of highs in the 60s and 70s prompted the red maples to flower and start producing seeds.

Red maple already gone to seed, Pittsburgh, 18 March 2024 (photo by Kate St. John)

Last Saturday I visited Wolf Creek Narrows, almost an hour north of Pittsburgh, where the growing season is later than at home. There we found an interesting jelly fungi called witches butter (Tremella mesenterica) …

Witches butter fungi, Wolf Creek Narrows, 16 March 2024 (photo by Kate St. John)

… and a decapitated skunk cabbage that allowed us to see the spadix inside. The hood usually covers this structure but something ate the hood. What animal could put up with the odor to eat that hood? And then the animal would vomit because the plant is toxic.

Skunk cabbage spadix revealed, Wolf Creek Narrows, 16 March 2024 (photo by Kate St. John)

I promised you an owl.

Inspired by Steve Gosser‘s photo of an American woodcock at North Park Upper Fields on 4 March, two of us stood out in the cold on Thursday evening waiting for sunset and for American woodcocks to make their twittering courtship flights. The sky was clear and the moon was so bright that we had moon shadows. It was also 5°F colder than at home in the city and I brought the wrong gloves. Brrrr!

Despite the cold it was worth the trip. Half an hour after sunset three American woodcocks put on a show and two flew right past us on their way to the sky.

American woodcock, North Park Upper Fields, 4 March 2024 (photo by Steve Gosser)

But the big surprise of the evening came before the woodcocks. Karyn saw a great-horned owl fly out of the pines and land on top of a brush pile. The owl was hunting while the voice of a youngster begged for food from pines.

Meanwhile a second adult owl flew to a bare tree at the other end of the field where we could see its silhouette against the glowing sky. Though my cellphone is not good at distance photos, you can faintly see the ear tufts that prove that this second bird of prey is a great-horned owl.

Great horned owl, North Park Upper Fields, 21 March 2024 (photo by Kate St. John)

Spring is getting interesting.

(credits are in the captions)

New Eagle Owl Baby at the National Aviary

Birds of Prey
Eurasian eagle-owl chick at the National Aviary hatched on 15 March 2024 (photo courtesy of the National Aviary)

22 March 2024

Eurasian eagle owls Dumbledore and X are parents again at the National Aviary. Their latest chick hatched on 15 March and is growing quickly and thriving in the Aviary’s Avian Care Center. You can see the chick and his caregivers through the Avian Care Center window.

When the chick hatched he weighed 55 grams (0.121 pounds, roughly the size of a small lime) but will grow so rapidly that in only eight weeks he’ll be fully grown, weighing up to 4kg (9 pounds!) with a wingspan of up to 6.5 feet.

I’ve said “he” for this chick but there is no way to visually tell whether he’s male or female. The National Aviary will do a DNA feather test to determine the chick’s sex.

Eventually he’ll look like his parents who lead active lives at the National Aviary. His father, Dumbledore, participates in flight shows and meets visitors when he’s not busy breeding.

Dumbledore the Eurasian eagle owl at the National Aviary (photo by meihua-stock via Pinterest and DeviantArt)
Eurasian eagle owl

photo by mishaleppert embedded via Flickr

I don’t have recent videos of X or Dumbledore (they’ve been busy off camera!) so to give you an idea of how big a Eurasian eagle owl is and how calm one can be as an avian ambassador, watch the public’s reaction when an owl visited the Hive Library in Worcester, UK with BBC Earth Unplugged.

video embedded from BBC Earth Unplugged

Guests are encouraged to drop by on weekdays to see the Eurasian eagle owl chick as he grows! He is the 11th chick his parents have hatched at the National Aviary over the years.

(credits and links are in the captions)

Flaco Died of a Window Strike

Bird Behavior, Birds of Prey
Flaco the Eurasian eagle-owl in Central Park shortly after he escaped his damaged cage, 18 Feb 2023 (photo from Wikimedia Commons)

1 March 2024

One week ago today, on 23 Feb 2024, the most famous owl in New York City hit a window on West 89th Street and died.

Flaco the Eurasian eagle-owl (Bubo bubo) escaped his enclosure at the Central Park Zoo more than a year ago after a vandal damaged it on 2 Feb 2023. The zoo tried to recapture him and worried that he would starve or be hit by a car. Instead Flaco thrived on his own and became a symbol of freedom to many New Yorkers.

A crowd watches Flaco on 18 Feb 2023 (photo from Wikimedia Commons)

He endeared himself to apartment dwellers by sometimes visiting their highrise windows or perching on their fire escapes.

Flaco peeping in a window in NYC, Dec 2023 (photo from Wikimedia Commons)

Sadly a window was Flaco’s undoing. Flaco’s biggest fan, David Lei (@davidlei), reported:

Memorials sprung up instantly.

Memorial to Flaco, the Eurasian eagle-owl, New York City, 25 Feb 2024 (photo from Wikimedia Commons)

Flaco’s death was covered in the New York Times: Flaco, Escaped Central Park Zoo Owl and Defier of Doubts, Is Dead and commented on by the zoo where he lived most of his life.

His story should not be over, though. Flaco was not the only bird to die of a window strike in North America. He was merely the most famous. Nearly one billion birds per year hit windows in the U.S.

If your home has ever experienced a window strike please implement one of these techniques to prevent further collisions and deaths.

Find out more at this vintage blog, written after one of our young peregrines died of a window strike.

Windows Kill

I hope Flaco’s death inspires everyone to do more to prevent bird deaths at windows.

(credits are in the captions)

Gentle With Their Young

Birds of Prey, Nesting & Courtship
Male Eurasian sparrowhawk plucking prey (photo from Wikimedia Commons)

23 February 2024

Birds of prey are fierce while they gather food but gentle with their nestlings. Watch as this mother Eurasian sparrowhawk (Accipiter nisus) protects her babies from the rain.

If she looks familiar it’s because Eurasian sparrowhawks (Accipiter nisus) are the same genus and slightly larger than our sharp-shinned hawks (Accipiter striatus). But female sparrowhawks are brown compared to males, whereas adult male and female sharp-shinned hawks wear the same colorful plumage.

Here are photos of all three: female Eurasian sparrowhawk, adult (male / female) sharp-shinned hawk, and male sparrowhawk.

Eurasian sparrowhawk, female in UK (photo from Wikimedia Commons)
Adult sharp-shinned hawk (left) + adult male Eurasian sparrowhawk (Wikimedia photos are at the links)

Did you notice the difference in eye color? Sparrowhawks have yellow eyes. Sharpies have orange eyes.

See more nature videos at Robert E. Fuller’s channel on YouTube.

(credits are in the captions)

First Egg at the Hays Eagle Nest, 2024

Birds of Prey, Nesting & Courtship
Hays bald eagle pair + first egg in nest, 21 Feb 2024, 6:57am (screenshot from the Hays Bald Eagle Nest Camera)

21 February 2024

If you haven’t been watching the Hays Bald Eaglecam, now is a good time to start. Sharp observers saw the first egg of the 2024 nesting season last night, 20 February 2024, at 8:16pm.

The female incubated all night long, then just before dawn she turned the egg for all to see.

Hays bald eagle female turns her first egg of 2024, 21 Feb, 6:50am (screenshot from the Hays Bald Eagle Nest Camera)

As the sun rose she settled down and her mate called to her.

Female eagle on the nest at Hays, 21 Feb 2024, 6:54am (screenshot from the Hays Bald Eagle Nest Camera)

… So she left the nest to perch next to him (shown at top).

First egg at the Hays bald eagle nest as seen on 21 Feb 2024, 6:55am (screenshot from the Hays Bald Eagle Nest Camera)

Watch for one or two more eggs in the days ahead and stay tuned for the first pip on this egg about 35 days from now. Here are all the links you need.

(screenshot photos from the Hays Bald Eagle Nest Camera)