Category Archives: Birds of Prey

Special Kestrels

Birds of Prey, Migration

American Kestrel, male (photo by Brian Herman)
Since I missed the Allegheny Front Hawk Watch last weekend I’m itching to go out there today — but I can’t, I have to work.  To compensate for this I spent time last evening looking through the hawk watch records at Hawkcount.org.  The statistics are fascinating and they support a hunch I started to develop last year.

Every fall I attend two hawk watches 775 miles apart.  In early September I visit the Cadillac Mountain Hawk Watch in Maine and see mostly American kestrels and sharp-shinned hawks, approximately one kestrel for every two sharpies.  Then in October/November I visit the Allegheny Front where the most common hawks are sharp-shins and red-tails in nearly equal numbers.  The kestrel count there is low, sometimes insignificant. 

I used to think my experience at Cadillac Mountain was normal for September and that I missed seeing kestrels at The Front because I visited it too late in the fall.  (That’s how I miss broad-winged hawk migration.)  But I had a hunch I’d got it backwards.  Perhaps, I thought, kestrels are scarce and my experience at Cadillac is unusual.

The numbers at Hawkcount.org bear that out.  Compared to the number of sharp-shinned hawks, kestrels are 40-60% as numerous at Cadillac but are only 4-10% as numerous in Pennsylvania.

Kestrels really aren’t a big item at most hawk watches and my experience isn’t “normal.”  I prefer to think of it as special.  Special, like the kestrels themselves who are one of the most beautiful raptors on earth.

(photo of a male American Kestrel by Brian Herman)

Sharp-shin

Birds of Prey

Sharp-shinned Hawk (photo by Kim Steininger)

With a look that strikes terror in the hearts of small birds, this sharp-shinned hawk hunted at Kim Steininger’s backyard feeders on a snowy winter day.

Kim was lucky to see him.  Though they’re present year-round in Pennsylvania and are the most numerous raptor at hawk watches this month, sharp-shins are very unusual in my Pittsburgh neighborhood in winter.

The last time I saw a sharp-shinned hawk was quite recent, though.  Last Monday I sat on top of a cliff called Giant Ledge in the Slide Mountain Wilderness of the Catskill Mountains and gazed to the east.  It was a chilly overcast day with no bird activity.  The maple and beech forest below me was clad in reds and yellows.  I could see for miles.  No birds.

Then one small hawk rose from the valley floor 1,000 feet below.  He circled to gain altitude and in a matter of minutes rose past my line of sight until he was above all the mountains.  Then he set his course and disappeared to the south.  Flap, flap, glide.

(photo by Kim Steininger)

Disease links T.Rex to raptors

Bird Anatomy, Birds of Prey, Musings & News, Peregrines
Hypothesized Trichomonas-like infection in T. rex (Illustration by Chris Glen, The University of Queensland from plosone.org)
Hypothesized Trichomonas-like infection in T. rex (Illustration by Chris Glen, The University of Queensland from plosone.org)

14 October 2009

For years people believed the holes in the jawbones of many Tyrannosaurus rex skeletons were evidence of fighting, even though they were too round and perfect for violent combat.  Recently paleontologists re-examined the holes with a new theory in mind and published their findings on PLoS One.

What lead them to the discovery was this thought:  Where have we seen holes like this before?  We’ve seen them on the jawbones of modern day birds of prey who suffered from a common avian parasitic infection called trichomoniasis.

Raptors, including peregrine falcons, catch trichomoniasis by eating diseased prey.  Peregrines are susceptible to it because they eat pigeons who carry the disease without showing symptoms.  Trichomoniasis invades the mouth and throat causing lesions which eventually penetrate to the bone.  The lesions block the throat making it hard to swallow and the raptor dies of starvation. 

When the paleontologists compared the holes on the tyrant dinosaur jawbones to those of raptors who had trichomoniasis, everything matched up.  The illustration at right shows how the infection would have looked on Tyrannosaurus rex with lesions both inside and outside mouth.  (Ewwww!)  Just like raptors, the tyrant dinosaurs would have caught it through feeding on diseased meat or by snout to snout contact. 

To me, the cool part of this discovery is that modern day birds are close enough to T.rex that they still suffer from a tyrant dinosaur disease. 

And it solved another mystery for me.  When peregrine falcon chicks are banded, the veterinarians always swab their throats with a long Q-tip to test for disease.  Now I know at least one of the diseases they’re looking for.

For more information on this discovery, click here or on the illustration to read the original article at PLoS ONE. 

(Illustration of trichomoniasis in T.rex, based on photographs of living birds suffering from the disease and bird necropsies, by Chris Glen, The University of Queensland.  Article Citation: Wolff EDS, Salisbury SW, Horner JR, Varricchio DJ (2009) Common Avian Infection Plagued the Tyrant Dinosaurs. PLoS ONE 4(9): e7288. doi:10.1371/journal.pone.0007288)

Single-mindedness

Bird Behavior, Birds of Prey
Red-tailed Hawk on Solomon's deck (photo by Michael Solomon)
Young red-tailed hawk on the back porch, August 2009 (photo by Michael Solomon)

23 August 2009

When you’re young you’re fearless.  You disregard life’s dangers because you can’t imagine anything will hurt you.  And when you’re busy you’re focused.  Very focused.

That’s what David Solomon’s family is learning from some immature red-tailed hawks in their neighborhood.  The Solomon’s have bird feeders that attract birds and squirrels which in turn attract young red-tails.

The hawks aren’t good hunters yet so they’re looking for an easy meal.  Their parents told them to watch out for humans but this hawk is so focused he doesn’t care that Michael Solomon is standing only a few feet away taking his picture.  In the young hawk’s limited experience people aren’t dangerous, so why care.

Immature red-tailed hawks must change this nonchalant attitude if they’re to survive to adulthood.  The birds travel long distances in their early years and, though most of the people they’ll encounter are in awe of hawks this close, there are still some people who will harm them even though it’s against the law.  It’s best to keep a wide berth.

In the meantime, hunger overcomes danger.  There’s something to be said for single-mindedness but it can be carried too far.

(photo by Michael Solomon)

p.s. Interesting articles:

Fine Weather for Vultures

Birds of Prey, Musings & News

Turkey Vulture at Shavers Creek (photo by Marcy Cunkelman)We’ve had a spate of hot, humid weather that’s finally going to break this weekend.  I shouldn’t complain – after all it’s August – but I’m no lover of heat and humidity and my nose tells me it’s time for a change.

My nose?  Well, I have a pretty good sense of smell.  Too good at times.  I love the scents of honeysuckle blooming, crushed mint leaves, warm pine needles, rain in the distance and damp earth at the end of winter.  (Remember the first day you smell the earth in spring?)

Right now the hot, soupy air is great for holding smells but the hotter it gets the more unpleasant some of those smells become.  I’ve been forced to think of this when, out on a walk, my nose suddenly detects spoiling food in a nearby garbage can or dog poo next to the sidewalk.  I give those spots a wide berth but the worst smells are hard to escape … the whiffs of something dead in the bushes. 

Fortunately turkey vultures have an excellent sense of smell and they love this stuff.  On my hikes I see them soaring overhead, sniffing the breeze, looking for the source of the smells I recoil from.

I hope they find that dead something-in-the-bushes.  They shouldn’t have much trouble.  It’s been fine weather for vultures.

(photo of a turkey vulture at Shaver’s Creek by Marcy Cunkelman)

Go Away!

Birds of Prey, Nesting & Courtship

Two Osprey at their nest (photo by Cris Hamilton)

…say this pair of ospreys from their nest at Shenango Lake in late May.  They already had babies and were wary of anything that might harm them.  Something overhead made them nervous.

Osprey nesting season varies across North America based on climate.  Osprey eat fish so they nest near lakes, bays, deep rivers and sheltered salt-water.  As with all birds, they migrate if their food supply is seasonal.  Fish migration (salmon and shad) and ice (which makes fish inaccessible) are determining factors.

Osprey reuse the same nest year after year by adding to the top of it, but they won’t return to the site until the ice is out.  In South Florida osprey don’t need to migrate so they begin nesting in November and December.  In southern New England, they nest in mid-to-late April because the ice doesn’t break until March.  Timing in Western Pennsylvania is similar to southern New England’s.

No matter where osprey nest, the process takes the same length of time:  37 days from egg-laying to hatch, 50-55 days from hatch to fledge, and 10-20 more days until the young are independent of their parents.   

By now, the babies from this Shenango Lake nest have flown and they’re learning the ropes of adulthood.  When the cold weather comes it’ll be their turn to go away.

(photo by Cris Hamilton)

Update on Gulf Tower peregrines and CMU red-tails

Birds of Prey, Peregrines

Peregrine falcon - probably Tasha - at the Oliver Building (photo by Heather Jacoby)Over the past few weeks I’ve put updates in the comments of other posts so you may have missed them. Here’s the latest on these two raptor families. 

Gulf Tower peregrine falcons: 
On Tuesday Heather Jacoby saw a peregrine falcon perched on a windowsill at the Oliver Building downtown (click here and here to see her photos).  Interestingly, Heather sent me this picture of Tasha doing the same thing a year ago.  For some reason the Queen of the Gulf Tower likes this spot in the summer.

Tasha’s two youngsters are doing well.  The young peregrine who hit her head and was rescued from the street on June 10th has fully recovered and was released on July 8th.  Beth Fife said, “She flew very nicely, circled and flew off.” I don’t know where she was released but it wasn’t downtown. She is now independent and on her own.

The other juvenile is also doing well. Around July 7th she was spotted perched on a high windowsill of the Frick Building, looking into an office to see what was going on. This is typical behavior for the downtown juvenile peregrines as you can see here.

CMU red-tailed hawks: 
The young red-tails born on the Fine Arts Building at Carnegie-Mellon University are almost independent now.  They’re flying well and able to chase their parents to beg for food.  During my lunchtime walk on Tuesday I saw both juveniles perched in a dead tree on Flagstaff Hill.  They were preening and sleepy but one of them whined occasionally just in case their parents needed an audio reminder.

I’m glad everything’s going well.

(photo by Heather Jacoby)

Eagle Day

Birds of Prey

Adult Bald Eagle at Crooked Creek (photo by Steve Gosser)

The Fourth of July is the one day every year when you’re certain to see a lot of bald eagles — on Tshirts, on banners, as statues on flagpoles, and as images superimposed on waving U.S. flags.

The patriotic illustrations are just an idea of bald eagles.  Fortunately it’s getting easy to see the real thing in western Pennsylvania nowadays.

Back in November 2007, I blogged about our bald eagle comeback after DDT caused a severe population decline.  In the 1980s the PA Game Commission conducted a reintroduction program.  Twenty years later the eagle population is growing throughout the state as you can see by the sightings posted in that blog’s comments.

The eagle pictured here is from Armstrong County.  I learned about him from Steve Gosser who made several visits to Crooked Creek Lake last winter to photograph birds.  Steve always found bald eagles there so when he heard they were nesting nearby he lugged his camera more than half a mile (uphill!) to try to get a picture of the nest.  After a half-mile walk the nest was still not close, but one of the adult bald eagles flew near him.  Nice picture!

Steve returned from time to time as winter turned to spring, hoping for another glimpse of the eagle family.  By June the young eagles were ready to fledge, walking all over the nest tree and flapping their wings.   Though the nest was far away, Steve took a picture and digitally zoomed it so you can see the young eagles.  Click on the photo to see for yourself.  The picture is grainy because it’s zoomed.  Notice that juvenile eagles are all brown!

If you hanker to see bald eagles this weekend there are many western PA counties where you can.  The best place by far is Pymatuning State Park in Crawford County.  In 2002 there were 14 bald eagle nests that fledged 20 young in Crawford County for a total of 48 eagles.  There are even more eagles today.  Back then there were only 67 eagle nests statewide.  This year there are 170 nests in Pennsylvania!

When you go to Pymantuning, stop by the PA Game Commission Wildlife Learning Center just past the spillway (where the ducks walk on the fishes’ backs).  Even if the Learning Center is closed on the day you visit, their patio has a great view of the lake where the eagles hang out. 

And take your binoculars.  I’m sure you’ll see a bald eagle.

(photo by Steve Gosser)

Red-tail Rescue: Act One

Birds of Prey
Red-tail fledgling rescued at CMU by Barbara Kviz (photo by Kathy Borland)
Barbara Kviz holding the rescued red-tailed hawk fledgling (photo by Kathy Borland)

16 June 2009

The drama began Sunday morning when Security Guard Andrew Loveridge found a red-tailed hawk fledgling hiding under a bush at Carnegie Mellon’s Hunt Library. 

No one saw the bird launch from his nest on the roof of the Fine Arts Building but he had obviously missed the tree he was aiming for, if he aimed at all. 

The fledgling looked fine except for a slight limp, perhaps from a botched landing.  To add insult to injury he was being harassed by a food item!  A squirrel was chasing him from bush to bush.

Andrew guarded the hawk and enlisted the help of Barbara Kviz who formulated a plan.  She called her friend Kathy Borland, a fan of this red-tail family since the nest began.  Kathy also works for CMU Security so together with Dorothy Kweller they corralled and captured the hawk.

They knew the bird shouldn’t be on the ground so they called Wildbird Recovery for confirmation. “Yes, he needs to be up high.  Put him in a tree and his parents will take over from there.”

Barb, Kathy and Dorothy tried placing him in a nearby tree but the only reachable limb was too low.  Then Kathy realized it would be an easy matter to put him on the roof.  With her help they went upstairs in the Fine Arts Building and carefully put the fledgling on the lower roof near his sibling. 

Next morning when I walked by both red-tail babies were lounging on the railing of the lower roof.  End of the Act One.

Let’s hope Act Two doesn’t require a rescue.

Whoops!

Bird Behavior, Birds of Prey

Great-horned Owl in ARL's flight cage (photo by Maria Pyrdek)When I received this picture from Maria Pyrdek it made me laugh out loud.  

This is one of Martha’s foster babies at Animal Rescue League’s Wildlife Center.  Martha’s the great-horned owl I wrote about on May 13 who’s raising orphaned nestlings. The baby owls are ready to fledge so they graduated to the flight cage. 

Martha moved with them to continue her fostering duties and give them additional tips on how to be good owls.  Click on the photo to see nearly the entire family – except this guy.

I wonder what Martha thought when he did this.  He can fly, but can he land?  What a hoot!

“Cut me a break,” he says, “I’m learning.”

(photos by Maria Pyrdek at the ARL Wildlife Center in Verona, PA.  Click on the owl’s photo to see Martha with the babies in the flight cage.)