Category Archives: Beyond Bounds

Why Are Penguins Black and White?

This 36-million-year-old penguin was not as good a swimmer as its modern relatives. (Illustration by Katie Browne/U.T. Austin, linked from sciencemag.org)
36-million-year-old penguin (illustration by Katie Browne/U.T. Austin, linked from sciencemag.org)

Why are penguins black and white?

There are many answers to this question but an intriguing one comes from the complete skeleton, including feathers, of an extinct penguin dubbed Inkayacu paracasensis, the “Water King.”

When the Water King’s skeleton was found on the Pacific coast of Peru in 2008, scientists had just recently discovered they could determine the color of fossil feathers by examining the size and shape of cellular structures called melanosomes.  Armed with this information they figured out that Inkayacu paracasensis was gray above and reddish-brown below.

On a skeletal basis he looked just like a penguin though at five feet long he was larger than any alive today.  By comparison the largest living penguin, the Emperor Penguin, is about four feet long.

But the Water King probably couldn’t swim as well as today’s penguins.  Scientists theorize that it’s because he wasn’t black.

Black pigment, called melanin, provides strength to the structures it colors.  For penguins the structures requiring the most strength are their wings because they use them to literally fly through water.  Water is 800 times denser than air so flying underwater is a very strenuous activity.

The Water King was gray, today’s penguins are black.  Are modern penguins black because melanin gave them stronger wings?  Maybe.

And why are penguins half white?   Perhaps because they’re better camouflaged underwater when their bellies are white.

But there’s more to the story.  Click here to read about the Water King and “How Penguins got their water wings.”

(Illustration by Katie Browne/U.T. Austin, linked from Science Now.  Click on the illustration to see the original in context.)

Beyond Bounds: White Tern

White tern (photo from Wikimedia Commons)

One of the fun things about doing research for my blog is that I sometimes find very cool information I never knew before. This bird is one such discovery.

The white tern (Gygis alba) is a pantropical bird with many names and an amazing habit.

It’s all white with dark eyes and a thick black bill that’s blue at its base.  In flight it’s buoyant and erratic with quick changes in direction and speed.  Perhaps this gave it a second name: fairy tern.  In Hawaii it’s called Manu-o-ku.

White terns eat saltwater fish and nest by the ocean but they never build a nest.  The female lays only one egg per clutch in whatever suitable depression she can find.  This could be on gravel, rock, or — most amazingly — on a tree branch.  Imagine this: an egg sitting all by itself on the branch of a tree.  Click here to see what this looks like!

If the egg isn’t blown off the tree, it stands a good chance of surviving because it’s in a sneaky place.  Both parents incubate, brood and feed the chick and when it’s independent in two months’ time, its mother may lay another egg on the same tree branch and start the process all over again.  In this way white terns can raise up to three chicks per year.

Their crazy nest site selection must work.  White terns are listed as “Least Concern” on the IUCN Red List with over 100,000 breeding pairs worldwide.

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

Prairie Falcon at Mud Level Road


I usually don’t chase rare birds because I am so disappointed when I drive a long way and don’t find what I came for, so in December 2005 when Andy Markel reported a juvenile prairie falcon in the open fields of Cumberland County north of Shippensburg I did not go see it.

Over the next few weeks Andy and others found and photographed the prairie falcon again and again.  It was so far out of range that many wondered if it was a falconer’s bird but no one could prove it.  The bird stayed through the winter and then was gone.

Prairie falcons (Falco mexicanus) are western birds of cliffs and open country.  They’re the same size and shape as peregrines except that they’re pale brown and white with dark axillaries (armpits) and pale heads.  They range from California to Colorado, from southern Canada to Mexico. They never come to Pennsylvania.

But this one does.  Every winter the prairie falcon returns to the same place on Mud Level Road.  Now, of course, it’s an adult.  In February 2008 it was found so easily that many birders made the trek to see it and even discovered that it roosts at a quarry a mile away from its daytime haunts.  (Prairie falcons like cliffs just as much as peregrines do.)

Still I did not go to see it.  The 3 hour drive from Pittsburgh was too long for the disappointment I was bound to encounter.

But this year the falcon came back early — November 20 — and I was going to be in Hummelstown for Thanksgiving, only an hour away.  Saturday morning, November 27, was my only chance to chase it.

Long before dawn I drove to Cumberland County and found two other birders already at the intersection of Mud Level and Duncan Roads.  Neither had found the bird but with more eyes on the sky we stood a better chance.

Soon we saw a falcon hazing the pigeons northwest of Mud Level but even through a scope the bird was impossible to identify.  Jonathan Heller and I drove to Brinton Road for a better look but could not relocate the bird.  Mike Epler stayed behind, then drove the circle.  No luck.

Back and forth we searched.  Jonathan and I tracked a falcon that didn’t look quite right but it was our best candidate.  We finally caught up to it just as it landed in a tree on Brinton Road.  We screeched to a halt, jumped out of our cars and identified … a merlin.

At any other time and place a merlin is a good find but we were disappointed.  This was made worse when Mike drove up and told us he had just seen the prairie falcon at Mud Level and Duncan.  He had watched it retrieve a mourning dove dropped by a harrier, then perch and eat the prey close enough for a great look.

Aaarrrgg!  We went back to our starting point but the bird was gone.

Jonathan was preparing to leave so I took a slow drive down Mud Level Road contemplating the ephemeral nature of rare birds.  I told myself that on this trip I’d heard horned larks and seen a merlin, kestrels, northern harriers and red-tailed hawks — and that should be enough.  Sigh.

No point in looking anymore.  Sigh.

I drove away slowly down Duncan Road.

A pale brown hawk, very pale, on a hay bale, caught my eye.  It had its back to me and was eating.  Oh my!  I pulled off the road and parked near the hay bale.  I rolled down the passenger window and had an excellent view of the prairie falcon as it ate a bird.

The falcon looked around, his cere and eyerings yellow, his legs brighter yellow, his head quite pale.

Though I stayed in my car I made him nervous.  He bobbed his head, then picked up his prey and flew to another hay bale.  In flight I saw his dark axillaries.  Again he was nervous, flew down to the ground, then eventually northwest across Mud Level Road.  Good bird!

I’ve now seen every falcon that normally occurs in North America except the aplomado.  (It occurs from Mexico to South America, rarely in the southwestern U.S.)

Needless to say the bird in this photo is not the one at Mud Level but it captures his look and posture.  For an even better look, click here for a flight photo and you’ll see the dark feathers under the wing.

(photo of a prairie falcon by Matt MacGillivray via Wikimedia Commons. Click on the photo to see the original)

Beyond Bounds: Brant


Here’s a beautiful picture of a bird we rarely see in southwestern Pennsylvania.  When we do it’s alone, flown off course while its companions migrated to the Atlantic coast on a route far north of Pittsburgh.

This is a brant, a small goose that nests in the Arctic and winters at the coast.  It resembles a Canada goose except that it’s much smaller, has a stubby bill, the shortest tail of any goose, and a dark head, neck and chest.

Sometimes brant, especially lone birds, hang out with Canada geese.  This may have saved them from extinction.  In the early 1930’s the brant population declined dangerously because the only food they ate — a marine plant called eelgrass — was in short supply.  Then they changed their diet to include grass and grain from agricultural fields, a habit they may have learned from Canada geese.  But they still prefer eelgrass.

If you want to see a lot of brant, visit the coast in winter.  Otherwise the only reliable place to find them in Pennsylvania is at Lake Erie during their October-November migration. 

Bobby Greene photographed this bird on Lake Erie at Conneaut, Ohio.

(photo by Bobby Greene)

Avoiding Unintended Consequences

Snail kite in Florida (photo by Steve Gosser)

15 November 2010

Chuck Tague sent me news from Florida Audubon of a well meaning plan to control an exotic plant that would have disastrous consequences for the snail kite.

Snail kites are unusual birds of prey with red eyes and deeply hooked beaks that specialize in just one food:  the apple snail, so-called because its shell resembles an apple.

Apple snails live in clean, warm, freshwater lakes and wetlands, so that’s where the snail kite lives too.  Most of the snail kite’s range is in South America.  In the U.S. they are found only in Florida but are increasingly rare and now considered endangered in this country.  Their population dropped from 3,000 in the mid-1990’s to only 700 birds today due to habitat loss, the degradation of the Everglades, and a huge drop in the population of native apple snails. 

But there is one bright spot.  Snail kites also eat the exotic invasive Island Apple Snail (Pomacea insularum), pictured here, that thrives in the presence of a plant called hydrilla.

Island apple snail (photo by Chuck Tague)

And that’s where the trouble begins.  Hydrilla is both exotic and invasive.  It jams boat propellers and clogs lakewater habitat, so to make room for navigation and native species the Florida Fish and Wildlife Conservation Commission planned control measures to get rid of it.  The problem is, if the hydrilla is gone, the population of island apple snails will crash and this will starve off the last remaining snail kites in Florida. 

That’s why Florida Audubon mobilized their members to attend a meeting in Kissimmee last week to urge Florida FWC and the U.S. Fish and Wildlife not to enact an aggressive hydrilla control plan at Lake Toho. 

Citizen comments prior to the meeting already helped the situation.  According to a Florida Fish and Wildlife news release, FWC and USFW modified their plan to clear hydrilla only from the navigation channels, making sure that enough hydrilla and apple snails remain to feed the snail kites. 

And so they’ll avoid the unintended consequence of extirpating snail kites from the United States.  

Read more about the snail kite’s tenuous life in FL here.

(photo of Snail Kite by Steve Gosser, photo of Island Apple Snail by Chuck Tague)

A Crow in Jay’s Clothing?


To those of us in eastern North America this bird looks all mixed up.

He has a crow head, blue jay colors and an incredibly long tail.  He resembles crows and jays because he’s a corvid.  We don’t see him in Pennsylvania because he lives west of Iowa and east of the Sierra Nevadas.  Say hello to the black-billed magpie.

I saw this bird once, but now my sighting doesn’t count.  Years ago I saw a magpie outside my airplane window as we taxied to the gate at Charles de Gaulle airport in Paris.  Then, in their never-ending quest to reclassify birds the American Ornithological Union split the black-billed magpie from the European magpie and this bird dropped off my life list.   He is now Pica hudsonia.  The bird I saw in Paris was a Pica pica.

If I visited open country in the western U.S. I could easily re-add this bird to my list.  Black-billed magpies are loud and conspicuous, midway in size between blue jays and American crows.  Like crows they are smart, omnivorous and versatile.  Their claim to fame is their very long tail (more than half their body length) and their huge ball-shaped stick nests.

Maybe I should fly to Denver and look out the airplane window.  😉

(photo by Julie Brown)

Beyond Bounds: Cryptic Forest Falcon

Cryptic Forest-Falcon (photo linked from MSNBC slideshow of the Amazing Amazon)
Cryptic Forest-Falcon (photo linked from MSNBC slideshow of the Amazing Amazon)

Here’s a bird I doubt you’ll ever see in the wild.

This is the cryptic forest-falcon (Micrastur mintoni) of the southern Amazon watershed.  It is so shy and so hard to see that until 2002 its museum specimens were thought to be a similar bird, the lined forest-falcon. Both have slate gray backs and red-orange cere and lores.

Forest-falcons hunt in thickly forested habitat so their bodies have many of the same characteristics as our accipters:  short rounded wings, long tails, and relatively long legs.  The cryptic forest-falcon is somewhat comparable in size and shape to our sharp-shinned hawk.

If you happen to go to the Amazon to look for this bird, good luck.  My raptor guide says it is “best located by song: single low-pitched notes uk, uk, uk..

Thanks to Diane Korolog for alerting me to this beautiful bird.

(photo is linked from MSNBC‘s Amazing Amazon slideshow.  Click on the picture to watch the slideshow. It is the second photo in the series.)

.http://msnbcmedia.msn.com/j/MSNBC/Components/Slideshows/_production/ss-101025-amazon-new-species/Micrastur_mintoni%201.ss_full.jpg

Stellar Steller’s

Steller’s Jay (photo by Michelline Halliday)

This western bird is “stellar” but that’s not how he got his name.

In July 1741 the German naturalist Georg Wilhelm Steller was given a single day to study North American species.  Fortunately it was a long day with more than 20 hours of available light.

Steller’s opportunity came at Kayak Island, Alaska while on Vitus Bering‘s ill-fated last voyage.  The expedition anchored for one day to take on water so Steller quickly went ashore to catalog new species.  They headed home for Siberia the next day but became marooned on Bering Island where many expedition members perished.  Steller’s specimen of the jay was lost but his description of it was not.  The jay was later named for him.

Steller’s Jay (Cyanocitta stelleri) ranges west of the Rockies from Alaska to Nicaragua.  It’s similar to the blue jay but its color varies from dark in the north to paler in the south.  Inland birds have white flecks on their crests, coastal birds have blue. 

I hadn’t realized they varied so much until peregrine fan Michelline Halliday sent me this photo of the male jay who claims her Seattle backyard.  He and his mate raised their family nearby and are quite bold when Michelline comes near. 

But that’s partly their nature. 

Steller’s jays are highly social and hang out in groups which are dominated by a mated pair.  The birds in charge are those whose nesting territory the group is visiting at the time.  This means the dominant pair changes within the group as the group moves around.

I like to think of it as a progressive dinner party.  As the diners move from house to house, the birds in charge are those who are hosting that portion of the meal.  When everyone moves to a new location the new hosts take over. 

And they sure are dressed in beautiful “clothes.”  No wonder I get confused about the spelling of their name.  Steller’s.

(photo by Michelline Halliday)

Migration Spectacle: Snow Geese!

11 March 2010

Snow geese are so unusual in southwestern Pennsylvania that it’s incredible there are 120,000 of them in the state — and none here — but that’s how many were at Middle Creek Wildlife Management Area yesterday.

Middle Creek is on the border of Lebanon and Lancaster Counties, squarely on the migration path of waterfowl travelling from the Atlantic coast to their breeding grounds in the Arctic and northern Canada.  In early March the lake hosts as many as 250,000 snow geese, 8,000 tundra swans and a wide variety of ducks.

I went there last Sunday to get my annual dose of birds.  The weather was great and all day long the waterfowl numbers increased.  As we watched from Willow Point more birds arrived from the south than flew off to the north.  Every day must have been like that this week.  There were 45,000 snow geese last Sunday.  Now there are three times as many.

Yes, 120,000 birds in a huge flock on a small lake.  Imagine when the entire flock takes off at once in fear of a lone bald eagle overhead.  Their flight is controlled chaos.  Such noise and excitement!   It’s a wonder they don’t hit each other in the air.

So if you can, set aside some time to visit Middle Creek this weekend.  (Click the links in the text above for more information.)

What a migration spectacle!

(photo by Kim Steininger.  We were both there last Sunday.)