Monthly Archives: December 2009

Anatomy: Patagium, Patagial

Patagial mark on Red-tailed hawk (phto by Chuck Tague)I came across the term "patagial mark" at the Allegheny Front Hawk Watch in November when I was having trouble identifying a passing red-tailed hawk.

Usually red-tails are easy for me to pick out by their size, shape and belly bands but the bird in question had a pale belly like the one pictured here, was far away and was fighting the wind.  A fellow birder pointed out that I could always identify a red-tailed hawk if I looked for the "dark patagial marks."


The patagium is the stretch of skin on the leading edge of the bird's wing extending from the head to the wrist.  The noun patagium is rarely used but its adjective form, patagial, is fairly common.

For instance, red-tailed hawks have light-colored underwings and a dark patagial mark, shown here circled in pink.  It's a good field mark because no other hawks in eastern North American have this combination.  Try comparing the underwings of red-tailed hawks to red-shouldered, broad-winged or (western) ferruginous hawks for a bit of fun.

Another use of the word is in "patagial tags" which are bird bands applied to the wing on large soaring birds so that researchers can read the tag while the bird is in flight.  The tag hangs below the wing so it doesn't interfere with the bird's ability to fly.  California condors, our biggest bird, have the biggest patagial tags.  Click here to see a patagial-tagged ring-billed gull Chuck Tague saw in Florida last winter.

So, yes, I knew about those dark spots on the red-tail's wings.  I just didn't know they were so unique.

(photo by Chuck Tague, altered to highlight the bird's patagial mark)

Beyond Bounds: Common Tern

Common Tern (photo by Brian Herman)
Beyond the bounds of southwestern Pennsylvania you'll see this bird nesting at the Atlantic shore, the Great Lakes, or interior Canada but the common tern is totally uncommon in Pittsburgh.

Common terns are found worldwide.  In this hemisphere they winter on the Pacific coast of Central America, on both coasts of South America and sometimes in the Caribbean.  I know they migrate to points north of Pittsburgh but do we ever see them here?  Rarely.

Brian Herman captured this one in breeding plumage at the Wetlands Institute, Stone Harbor, New Jersey.

(photo by Brian Herman)

Want to see eagles?

Immature Bald Eagle, Crooked Creek (photo by Steve Gosser)

Bald eagles, that is. Though most birds have left the northern part of the continent by now, December is a great time to see these majestic birds of prey. 

Bald eagles are sea eagles, more closely related to white-tailed eagles than to goldens, so you'll always find them near open water.  As the lakes freeze up north, bald eagles move south and then to the rivers.

Near Pennsylvania the best place by far to see winter eagles is at Conowingo Dam on the Susquehanna River in Maryland.  Unfortunately Conowingo is a 4.5 hour drive from Pittsburgh so when I don't have the time to make the trip there are places in western Pennsylvania where I can find an eagle or two - or more.

Pymatuning is one such place, about two hours away.  Bald eagles live at the lake year round and nest within sight of the Game Commission Wildlife Learning Center. It's easy for them to stay all year, even in freezing conditions, because there's always some open water at the spillway.

Even closer and only a 45-minute drive is Lake Arthur at Moraine State Park, a good place for eagles when the lake's not completely frozen.  The Three Rivers Birding Club held an outing there last Saturday and was treated to a heart-stopping moment when a pair of bald eagles attacked a flock of coots.  Watch the 3RBC website and their newsletter, The Peregrine, for details on what happened next. 

You can also find bald eagles at Crooked Creek Lake in Armstrong County, only an hour away.  A pair of eagles nested there last year and are courting now in preparation for nesting in January.  I saw both adults last weekend plus two of their "kids" as I watched from the Overlook.  Marge Van Tassel and Steve Gosser tipped me off to this site. Shown above is Steve's picture of one of the immatures taken on December 5th.  Nice, eh?

And the colder it gets, the more likely you won't even have to leave town to see an eagle.  As the lakes freeze bald eagles will come to Pittsburgh's three rivers.  Watch the Allegheny, Monongahela and especially the Ohio at Dashields Dam. 

Far or near, December's a good time to see "sea" eagles.

(photo by Steve Gosser)

At the Roost

Cloud of European Starlings (photo from Shutterstock by Vasily A. Ilyinsky)
Saturday, 4:30pm:  I'm driving down Fifth Avenue on my way home from Armstrong County when I see a constant stream of crows flying high on their way to Oakland.  They're heading for the roost but where, exactly, would that be? 

"Aha!" I thought. "I'll follow them."

This was easier said than done.  Crows don't pause for stop lights and their flight path was not aligned with any one street.  For about a mile I drove from stop light to stop light cursing the traffic signals and rapidly losing sight of the crows.  Lost them!  Then I remembered that my friend Karen told me a huge flock of crows gathered at the corner of Bigelow Boulevard and Craig Street nearly every evening last week. Why not try there?

I didn't see another crow until I arrived opposite the Marriott Residence Inn on Bigelow Boulevard.  Talk about birds!  Thousands of robins, crows and starlings filled the sky.  The robins made beeline flights across the street into the trees.  Crows arrived in a steady stream from the north and gathered on the hilltop. 

The starlings were the best.  They popped off the Residence Inn in great "balls of birds" like the picture above.  On and on, they flew in undulating circles getting ready to settle for the night.  Just when I thought they'd stop, a Coopers hawk zipped by and chased several birds in the half-light.  The crows didn't care - they had already begun to move down to rooftops on Melwood Street - but the robins went nuts and two flocks of starlings made another pass in very tight ball formations.  Around and around they flew.  The Coop made a couple more attempts but struck out every time. 

Eventually it was too dark to see so I went home, congratulating myself that I'd found the roost. 

Well, not exactly.

The robins and starlings may be there but last night the crows were not.  Karen found them above Polish Hill and moving down to the Strip District. 

Nothing is quite so humbling as being fooled by thousands of crows.

p.s. Don't miss the starling show on Bigelow Boulevard or at the Birmingham Bridge at dusk.  Wow!

(photo of a swarm of European starlings by Vasily A. Ilyinsky from Shutterstock)

Participate in a Christmas Bird Count

Birders on Pitt Sciences outing 2006 (photo by Z Taylor)
Today, 14 December 2009, begins the 110th Christmas Bird Count, scheduled every year between December 14 and January 5.

Each count is held in a 7-mile radius circle during a single 24-hour period (night hours are for counting owls!) and though most count circles are in the U.S. there are also counts in Canada, Mexico, Central and South America.

Volunteers organize the routes so they don't overlap, then tally the number of birds per species, weather conditions, number of observers, hours spent and miles traveled.  The statistics allow Audubon to compare year to year, correcting for differences in participation and coverage.  It's the longest running wildlife census in the Western Hemisphere.

Though the count period begins today, most counts are scheduled on Saturdays and Sundays so there's still plenty of time to sign up.  For instance, the counts near Pittsburgh will be:

  • Beaver in Beaver County,  Sat 12/19/09
  • Buffalo Creek in Washington County (IBA 80), Sun 12/20/09
  • Buffalo Creek Valley in Butler & Armstrong Counties, Sat 12/19/09 (Yes, there are two big creeks named Buffalo in our area. Confusing!)
  • Bushy Run park in Westmoreland County, Sat 12/19/09
  • Butler in Butler, Lawrence and Mercer counties, Sat 12/19/09
  • Pittsburgh in Allegheny County, Sat 12/26/09
  • Pittsburgh South Hills in Allegheny and Washington Counties, Sat 12/19/09
  • Rector in Westmoreland County, Sat 1/2/10
  • Washington in Washington County, Sat 12/19/09

It's easy to participate.  You can count in the field with other participants; go with friends or meet new ones assigned by the coordinator.  If you live in the count circle you can count the birds at your feeder.  Just contact the count coordinator and he or she will handle the rest.

For contact information on all the Pennsylvania Christmas Counts, click here and go to pages 6-8 of the Pennsylvania Society of Ornithology newsletter.  (The counts are listed by count name.)  For other locations, check the Audubon Christmas Bird Count website to find a count near you and contact information for the circle coordinator.

I'll be participating in the Buffalo Creek count in Washington County (IBA 80) organized by Larry Helgerman on Dec 20th.

Pick a count.  Have fun!

(photo by Z Taylor, taken at a Pitt Sciences outing in 2006)

Anatomy: Alula

Peregrine falcon with alula shown (photo by Jack Rowley)
This is my favorite part of bird anatomy because I see peregrine falcons use it to such good advantage.

The alula is the bird's "thumb" positioned on the top edge of the wing and covered with three to five small feathers depending on the species.  Normally it lays flat on the wing and is hard to see but birds raise their alulas to prevent a stall during slow flight.  In this position the air can flow faster over the top of the wing, creating lift when the wing is perpendicular to the ground.  Wikipedia explains that this allows "a higher than normal angle of attack" which is exactly what Dorothy (the adult female peregrine at Pitt) is doing here -- attacking the bird banders who are coming for her babies.

Big airplanes solve the same problem of creating lift with movable parts called slats that act like alulas.  Look out the window of a jet before take-off and you'll see the slats have been moved away from the leading edge of the wing.  Lift!

So when you see a bird landing or attacking, look for its alulas.  I've circled one of Dorothy's in red so you know what to look for, or check yesterday's blog and you'll see both alulas on the great egret, raised like thumbs pointing to the sky.

(photo by Jack Rowley, modified to show the alula)

Beyond Bounds: Great Egret

Great Egret (photo by Chuck Tague)
Another beauty from beyond the bounds of southwestern Pennsylvania, this photo by Chuck Tague is one of my favorite pictures of all time.

Great egrets are unusual in the Pittsburgh area.  We see three to six per year during migration and I have never, ever seen one do this but Chuck spends his winters in Florida and has more opportunities than I do.

Chuck tells me this wingspread pose is a fishing strategy.  To me it is angelic.

(photo by Chuck Tague)

Penn State relocates its winter crows… again

Crow roost in Lancaster ,PA (image from Penn State Univ study)

Pittsburgh and Wheeling aren't the only towns with big winter crow flocks.

I read in yesterday's Centre Daily Times that Penn State is tired of the 3,000 crows who come to campus every winter and roost in the big trees around town.  The poop is getting to everyone, so staff from the Office of Physical Plant are spending this week making a heck of a lot of noise to get the crows to move.  They have experience doing it.  This is their second winter of "The Crow Wars."

Beginning about an hour after sunset, OPP staff shoot fireworks and noisemakers into the sky with the object of scaring the crows to a less populated roosting location.  Crows like to sleep with the lights on so Penn State floodlit a stand of trees at a preferred roosting site by the Visitors Center.  "Preferred" by humans, that is.

Will the crows take the hint?  Will they learn to love the Visitors Center?  Only time will tell.


(December 2011 note:  The original Centre Daily Times article has disappeared from their website. The photo above is from a Penn State News slideshow about Margaret Brittingham's & Grant Stokke's Lancaster crow roost study. Click on the photo to see the original.)

Learning Bird Song

Know Your Bird Sounds, CDs on Shop WQEDAs I mentioned last month, winter’s a great time to study birds indoors. One skill I like to brush up on is my ability to identify birds by sound. It takes a while to learn this skill but it’s well worth the effort because you always hear more birds than you can find with binoculars.

Interested in learning? Here’s how.

First, get your hands on one or more of the many fine recordings specifically geared toward learning bird sounds. These come in many formats: CDs, iPod files, iPhone apps and web-based recordings. The best learning tools include audio explanations with each bird call.

Then, set aside some time to listen and learn at your own pace. You can learn indoors but you’ll need to practice in the field, too. Winter may seem like a bad time to do this but it’s great for learning the basic sounds of resident birds without the springtime confusion of all the birds singing at once.

The two instructional series I know best are the CDs I use myself: Peterson’s Birding by Ear and Lang Elliott’s Know Your Bird Sounds. Both cover the birds of eastern and central North America and include a booklet with the CD.

The Peterson series is good for spring and summer because it focuses on songs, the sound birds make during the breeding season. Species with similar songs are grouped together with tips to tell them apart so you can compare the sounds and identify them more readily in the field.

In winter like to use Lang Elliott’s Know Your Bird Sounds, pictured here, because it includes all the sounds each species makes, not only their songs but the sounds you’ll hear right now: contact calls, alarm calls and even the whistle of their wings (e.g. mourning doves). The booklet describes the basics of bird song and Lang Elliott's soothing voice announces the bird, describes the type of call you're about to hear and explains the situations in which the bird makes the sound.

Want to get started right away?  The Lang Elliott CDs are available on the Shop WQED website. Just click on the picture above and scroll down the page to purchase one or both CDs.

And remember, be patient as you learn. This skill will take years to perfect and even the best birders need to brush up on it. 

…In fact, I think I’ll go listen to my CDs.

(photos from Shop WQED's Nature category)

Passing Through

Flock of Tundra Swans (photo by Steve Gosser)
I heard them before I saw them.

I was walking by the lake at Moraine State Park yesterday when I heard the whoo-ing of tundra swans in the northwest.  It took me a while to find them overhead because they were white birds against a whitish blue sky and they were very high up.

Through binoculars I counted 24 birds with their leader far ahead of the V.  As I watched, all the birds in the flock - except the leader - cupped their wings and lowered their feet as if to descend to the lake.

The leader kept flying.  "Don't stop now," he seemed to say, "We have too far to go."  The flock regrouped and followed him southeast.

Just passing through.

(photo by Steve Gosser)