Archive for the 'Birds of Prey' Category

Jan 29 2016

How To Raid A Wasps’ Nest

There’s a bird of prey in South America that likes to raid wasp nests to eat the larvae.  The problem is that red-throated caracaras (Ibycter americanus) have bare skin on their faces and throats, an easy target for stinging wasps.

How do the birds get the larvae without a lot of pain?  Do they chemically repel the wasps?

In 2013, Canadian Sean McCann and colleagues studied red-throated caracaras in French Guiana on the north coast of South America.  They learned that, no, the birds don’t repel the wasps.  The caracaras are attacked but they compensate in other ways.

Watch the video to see how the birds nab their tasty meal.  They know something about wasp behavior that we had been ignoring.

Click here to read more in their PLOS ONE paper, Strike Fast, Strike Hard, or here at

(video from YouTube)

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Jan 27 2016

Eagle Season Starts With A Bang!

Harmar Bald Eagle carrying nesting material, March 2013 (photo by Steve Gosser)

Harmar bald eagle carrying nesting material in March 2013 (photo by Steve Gosser)

For one of Pittsburgh’s three bald eagle pairs, this year started off with a bang.

Since late 2013 the Harmar pair that nests along the Allegheny River have been hard to observe because PennDOT blocked off the nearest viewing area while building a replacement for the 107-year-old Hulton Bridge.  Steve Gosser took the photo above from that viewing location in March 2013. It’s been hard to get good photos for years.

Last October the new bridge was completed and dedicated but the eagle viewing area was still closed while PennDOT began to deconstruct the old bridge.  However …

Yesterday morning, in a flash of light and sound, the old Hulton Bridge was imploded into the river.  Here’s a video from Dave DiCello, posted at The Hulton Bridge Blog on Facebook. (Dave also filmed the Greenfield Bridge implosion last month.)


Staff from the Audubon Society of Western Pennsylvania were on hand to monitor the eagles just in case.  As ASWP reports below, the eagles weren’t affected at all. They were 3.4 miles away as the crow flies.  (The eagles would have flown along the river, which is even longer.)

The Harmar eagles were down river near the Fox Chapel Yacht Club at the time. Our staff member monitoring the eagles said that the birds “didn’t even flinch” at the sound of the implosion.

The eagle viewing zone at Harmar will be closed a while longer but you can watch this pair easily now on the Audubon Society of Western Pennsylvania website.  ASWP has both the Hays and Harmar eagles’ nests streaming live at Click here to watch.

And for more images of the Hulton Bridge coming down, check out The Hulton Bridge Blog on Facebook and this story with videos at KDKA.


(photo of Harmar female eagle in March 2013 by Steve Gosser. Video by Dave DiCello)

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Jan 21 2016

Lead Poisoning Kills Birds

Published by under Birds of Prey

Bald Eagle in rehab for lead poisoning at Medina Raptor Center, Medina, OH (photo by Debbie Parker)

Bald Eagle in rehab for lead poisoning, Medina Raptor Center, Medina, OH, January 2009 (photo by Debbie Parker)

On Throw Back Thursday:

The news from Flint, Michigan about lead in their water supply reminds me that I wrote about lead poisoning in birds back in 2009.  Sadly not much has changed.

Though the U.S. has banned lead shot in wetlands, it’s still present in fishing sinkers and the bullets used in deer hunting.  Scavenging birds, including bald eagles, eat the gut piles hunters leave behind and are poisoned by the bullet fragments.  Many die.

A 2012 bald eagle mortality study in the Upper Mississippi Valley found that 60% of the dead eagles had detectable concentrations of lead in their livers. 38% had lethal levels.

In 2012 USFW researchers examined 58 dead bald eagles and identified lead exposure as a significant mortality factor (photo from USFW)

In 2012, researchers examined 58 dead bald eagles and identified lead exposure as a significant mortality factor (photo from U.S. Fish and Wildlife, Midwest Region)

Sadly, the problem is seen too often by veterinarians and wildlife rehabilitators.

Back in January 2009 I wrote about the dangers of lead poisoning and the sick eagle, pictured above, who was treated at Medina Raptor Center, Ohio. Click here to learn more in this 2009 blog post: Lead Poisoning


(photo from Wikimedia Commons. Click on the image to see the original)

p.s. Last year California became the first state to ban lead in bullets.  They are phasing them out over a period of five years.

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Jan 20 2016

The Tickbird

This week I blogged about a caracara on a capybara but I didn’t tell you much about the bird.  Why was the bird standing on the mammal?  Hint: The falcon’s nickname is “tickbird.”

Yellow-headed caracaras (Milvago chimachima) are omnivorous members of the falcon family who live in south-Central and South America.  They eat almost anything — carrion, frogs, fish, eggs, palm fruit, corn, horse dung — but when it comes to feeding their young they focus a lot on insects.  90% of the nestlings’ diet consists of beetles, grasshoppers and crickets.

They earned their nickname “tickbirds” because they also glean ticks off of cattle and other mammals, including capybaras.  Above, a juvenile yellow-faced caracara cleans a cow.  The cattle don’t mind, even when the caracaras pick at open wounds.

Yellow-headed caracaras have adapted well as the forest is converted to ranches and cities.  When they aren’t picking ticks off cattle they’re gregarious in town.  You’d never guess from this video that their nickname is The Tickbird.


(videos from YouTube. The second video was filmed in Cali, Columbia)

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Jan 17 2016

Whose Voice Is That?

Blue jays mimic the sounds of raptors to warn (or fool!) other blue jays.

In Pittsburgh they often mimic red-tailed hawks.  In Florida red-shouldered hawks are much more common so the jays imitate them instead.

This video from MyBackyardBirding in Florida is a good example of how blue jays can sound like red-shouldered hawks.  Can you tell who’s who when they aren’t on screen?

The mourning dove seems to be having a hard time figuring it out.


(video from MyBackyardBirding on YouTube)


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Jan 15 2016

A Conversation Between Two Birds

During the snowy owl irruption two years ago, John Dunstan recorded this video of a raven and a snowy owl having a conversation.

The raven says many things.  The snowy owl is unimpressed.

Notice at 1:20 in the video that the top of the raven’s head seems to grow “ears.”  This dominance gesture means “I’m big! Watch out!”  The owl doesn’t care and reaches over to peck the raven at 1:44.  The raven’s ears go down … but up again at 2:09.  What’s going on?

John Dunstan asked raven expert Bernd Heinrich, author of The Mind of the Raven, for an explanation and put Heinrich’s reply in the video description:

Naturalist Bernd Heinrich, author of “The Mind of the Raven”, was nice enough to provide this description.

Hi John,
The first thing to notice is that the owl is TOTALLY unimpressed. It’s not scared in the least, and the raven has no aggressive intentions, but starts out being just curious – like: “what the hell is This!” So it tests – tries to get a reaction. But the owl still stays totally nonchalant. At some point the raven then tries a different tactic – it puts on its “I’m a big guy” display of erect “ear” feathers – usually used to show status in the presence of potential superiors, but here used also with a bowing and wing-flaring, which is used in supplication if there is NOT going to be a challenge – so, yes, I think the raven was having fun, and then also starting to have some respect, because this big white thing was NOT going to cooperate and be its toy. 

The comments on the video are priceless!  Click here to see the video on YouTube and read the comments.


(video by John Dunstan on YouTube)

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Jan 07 2016

TBT: No, they won’t eat corn

Coopers hawk (photo by Chuck Tague)

Coopers hawk (photo by Chuck Tague)

On Throw Back Thursday (TBT):

When a Cooper’s hawk eats a bird at your feeder, it makes you think.

Click here for some thoughts on carnivorous birds — No, they won’t eat corn  — from 2008.


(photo by Chuck Tague)


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Dec 18 2015

Snowy Owls At Sea

Snowy Owl, Amherst Island, 2008 (photo by Kim Steininger)

Snowy Owl, Amherst Island 2008 (photo by Kim Steininger)

(A day late for Throw Back Thursday…)

Did you know that some snowy owls stay on the Arctic Ocean all winter?  Seven years ago satellite tracking technology revealed their unusual lifestyle.

Read more about the snowy owls who live on ice in the dark in this 2008 article:  Surprise! We hunt at sea.


p.s. Ever since the snowy owl irruption of 2013-2014, Project Snowstorm has satellite tagged and tracked some of the snowy owls who visit the Lower 48 States.  Click here to see maps and follow their stories of these amazing birds.

(photo by Kim Steininger)

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Dec 16 2015

Where Do The Golden Eagles Go?

Golden eagle at the Allegheny Front Hawk Watch, 1 Nov 2011 (photo by Michael Lanzone)

Golden eagle at the Allegheny Front Hawk Watch, 1 Nov 2011 (photo by Michael Lanzone)

In late autumn birders visit the Allegheny Front Hawk Watch, hoping this iconic bird will fly by.  On a good day more than 30 golden eagles migrate past the site.

After years of observation we now take for granted that golden eagles use the Allegheny Front as a migration corridor but that wasn’t always the case.

Golden eagles (Aquila chrysaetos) occur worldwide in the northern hemisphere but their stronghold in North America is in the American West.  They’re rarely seen in the East so it was a surprise when people saw so many at the Allegheny Front.

Where were they coming from?  Where were they going?

The answers remained a mystery until 2006-2007 when Dr. Todd Katzner, Dr. Trish Miller and Michael Lanzone, fore-runners of the Eastern Golden Eagle Working Group (EGEWG), fitted a few eagles with satellite transmitters.  The data showed those birds bred in Quebec and spent the winter in the mountains of West Virginia, Virginia and Kentucky.

This tantalizing information got a boost when the group upgraded their tracking equipment.  Beginning in 2008 most of the birds were fitted with GPS-GSM units that record more frequent data points and transmit over the cell network.

Here’s an EGEWG map from Katzner Lab showing movements of 14 golden eagles, Spring 2012 to Winter 2013.  These eagles were fitted with GPS-GSM units.  (Solid lines are winter/summer homes; dashed lines are migration.)

Golden eagle movements in eastern North America, satellite telemetry, Spring 2012-Winter 2013, part 2 (map courtesy of Katzner Lab)

Golden eagle movements in eastern North America, satellite telemetry, Spring 2012-Winter 2013, part 2 (map courtesy of Katzner Lab)

Thanks to many years of tracking, we now know that the golden eagles of eastern North America breed in Canada and spend the winter in the southern and central Appalachians.  This information, plus on-going research, helps protect the eagles and their habitat.

Click here to view maps at Katzner Lab and find out where the golden eagles go.


(photo by Michael Lanzone, Cellular Tracking Technologies)

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Dec 09 2015

Get Ready For Eagle Season

Published by under Birds of Prey

Bald eagle at Hays, PA, 21 Nov 2015 (photo by Dana Nesiti, Eagles of Hays PA)

Bald eagle at Hays, PA, 21 Nov 2015 (photo by Dana Nesiti, Eagles of Hays PA)

Though it’s only December, Pittsburgh area bald eagles are getting ready for nesting season. They’re starting now because the females will lay eggs in February.

Those who don’t have a nest site are scouting new territories and those who do are staying near home to keep the scouts away.  Meanwhile the immature set, ages 1-3, are loafing where the fishing is good up and down the rivers.

At the Hays bald eagle nest site, Dana Nesiti has been photographing the eagles whenever he can.  He took this beautiful photo on November 21.  Click on it to see more of his work at Eagles of Hays PA Facebook page.

Up the Allegheny at Tarentum, observers have seen lots of peregrine-eagle interactions since a pair of bald eagles moved into the area.  Even though the female peregrine, Hope, left Tarentum for Pitt, a single peregrine is still present at the bridge.  Mary Ann Thomas wrote about it at TribLive here.

So if you haven’t already, now’s the time to start looking for eagles along our rivers.  Check out the established nesting territories at Hays, Dashields Dam, and Harmar.  Keep your eyes peeled for new pairs at Tarentum and beyond.

Get ready for eagle season!


(photo by Dana Nesiti, Eagles of Hays PA)

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