Category Archives: Birds of Prey

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)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.

(photo by Kathy Borland of Barbara Kviz holding the rescued red-tailed hawk fledgling)

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.)

Foster Mom

Birds of Prey, Nesting & Courtship

Great-horned Owl fosters 3 babies at ARL Wildlife Center (photo by Galen Grimes)Humans aren’t the only ones who raise foster families. Right now a great horned owl named Martha is raising three foster chicks at the Animal Rescue League (ARL) Wildlife Center in Verona.

Martha herself is a rescued bird. She came to ARL five years ago when she was found starving and unable to fly because her wing had broken and healed in the wrong position. Her wing can’t be repaired so she’s a permanent resident at the Wildlife Center. Most of the time she’s an educational bird, teaching people about owls, but in the spring she becomes a foster mother.

This year Martha is especially busy raising three owlets. Jill Argall, Director of ARL Wildlife Center, told me their stories.

The first baby great-horned owl was from a nest in an old structure being demolished in Penn Hills. The nest was so high and the structure so unstable that the Game Commission had to use a lift truck to rescue the owl.

The second was rescued in Sarver when his nest fell out of a tree. His nestmate died in that incident and he was lucky to survive.

The third nestling was found on the ground in Fox Chapel. The people who found him waited and watched for his parents to tend to him but for two days the baby owl never moved and his parents never came so he was brought to the Wildlife Center.

Martha is in her glory right now teaching owlets how to be grown up owls. When their flight feathers are fully grown they will move to the flight cage where they’ll have room to learn to fly and hunt. When they’ve mastered both skills each owl will be taken back to his original home and released into the wild.

To read more about Martha at the start of her fostering season, see page 5 of ARL’s Sunny Gazette, Spring 2009.

And if you find a baby bird and don’t know what to do, read ARL Wildlife Center’s advice here or call them at 412-793-6900.

(photo by Galen Grimes)

Falconry Moment

Birds of Prey

Kate St. John holding a falconry Harris Hawk (photo by Mike Fialkovich)Last Wednesday, for the first time ever, I held a Harris’s hawk on my hand. 

My opportunity came at the Three Rivers Birding Club meeting when master falconer Jeff Finch, president of the Pennsylvania Falconry and Hawk Trust, presented a program on falconry. 

Jeff taught us about the rules and traditions of falconry, a hunting technique that’s at least 4,000 years old.  In it, the falconer and his bird go to the field and look for prey.  The falconer stirs up the prey, the bird flies to the kill.  What they hunt depends on the bird’s natural hunting technique: ground-based prey (rabbits, squirrels, muskrats) for red-tails, harris’s and goshawks; ducks and pheasants for peregrines.  Sometimes more than one prey item is caught per day but it doesn’t go to waste.  The falconer brings it home to feed his birds throughout the year.

Falconry is hard work and a lifetime commitment, not only to train and care for the birds but to hunt with them all season – September through March.   For falconers it’s a passion, a life-changing experience.  We saw how falconers bond with their birds because Jeff brought his male American kestrel and female northern goshawk and master falconer Richie (I didn’t catch his last name) brought his Harris’s hawk. 

The birds were gorgeous.  It was such a treat to see them up close.  Here I am holding the Harris’s hawk while Richie stands just outside the picture to the right.  The hawk is wearing a falconry hood so you can’t see its face.  (Click here for a better view of this species.)  And don’t be fooled by my expression.  My brows are knitted because I’m squinting.  Those glasses in my right hand should be on my face!

Because of the peregrines, I have a special place in my heart for falconers whose passion, knowledge and breeding birds helped make the Peregrine Recovery Program such a success. 

For more information on falconry in Pennsylvania, contact Jeff Finch at the Pennsylvania Falconry and Hawk Trust.  

(photo by Mike Fialkovich)