Outside My Window

You’d think I’d be sorry to be back in Pittsburgh (since last Tuesday night) but I learned that birding is not always a warm weather sport, even in a warm weather location like Florida. 

Here I am at Matanzas Inlet on February 19th.  Notice my coat, hat and gloves.  

I didn’t notice when Chuck Tague took this picture because I was so absorbed in a drama unfolding on the water.  The tide was going out and the fish were caught in the current.  This spawned a feeding frenzy of gulls and terns who dove to catch the fish while others chased to steal them.

As I watched, a royal tern caught a particularly beautiful long, thin, silver fish almost like an eel.  The laughing gulls chased the tern but he evaded them until a great black-backed gull tackled him and slammed him down on the water.  The gull sat on the tern, grabbed him by the back of the neck and pulled his head back until he could see the tern’s beak.  By then the tern had dropped the fish and there was nothing to steal.  Disappointed, the gull let the tern struggle free. 

What a bully!  I felt bad for the tern.  The gull didn’t win his dinner but he won my respect. 

(photo by Chuck Tague)

Huge flightless birds occur on many continents.  The ostrich lives in Africa, emus and cassowaries in Australia, rheas in South America and the giant moa, now extinct, in New Zealand.

For a long time scientists thought all these birds had a common flightless ancestor which lived on the mega-continent Gondwana before it separated into today’s smaller continents.  The theory was that the flightless birds were stranded on their separate lands and then diverged.

But now, thanks to DNA sequencing of the giant moa, scientists at Australian National University (ANU) have shown that its nearest ancestor is a small flying bird, the tinamou of South America.  Long after Gondwana broke apart the tinamou flew to New Zealand.  Millions of years later some of its descendants had evolved into the giant moa. 

Why did this happen?  The ability to fly is such a huge advantage, how could these birds afford to lose it?  ANU’s molecular dating suggests that the flightless species had been flying birds who fed on the ground and could run well.  When the dinosaurs went extinct there was suddenly a lot of food, fewer predators and less need to fly to escape them.  Over time some ground-dwelling birds became quite big and heavy.  They didn’t need to fly and eventually they couldn’t. 

Voila the ostrich!  An unexpected outcome from of the extinction of the dinosaurs.

For more information see this article in Science Daily.

(photo by Nicor from Wikimedia under Creative Commons Share Alike 3.0 license)

Some species are so completely monogamous that, once mated, the pairs stay together for the rest of their lives.  

This level of faithfulness is rare. Humans strive for it but we and many other species tend to practice serial monogamy: pairing with one mate, then breaking up and pairing with another. 

For tundra swans (whose subspecies include Bewick’s swans) their pairings are truly “Til death do us part.”  Swans are so wedded to their one mate that a widowed swan may not choose a new mate for a very long time — if ever.

So it was with great surprise that staff at the Wildfowl and Wetlands Trust Centre at Slimbridge, UK noticed that a pair of Bewick’s swans had apparently divorced.

Bewick’s swans nest in Siberia.  The western group spends the winter in Denmark, the Netherlands and the British Isles, returning to the same site year after year.  Because each Bewick’s swan has a unique yellow and black bill pattern, naturalists at Slimbridge are able to identify the individual swans who come to their refuge.

That’s how they found out that Sarindi and Saruni had split. 

This fall Sarindi came back to Slimbridge with a new mate so naturalists feared the worst - Saruni was dead.  But then she arrived with her new mate and there they were, all four birds on the same lake and the former couple not acknowledging each other. 

No one knows why this pair went their separate ways but it’s such a rare occurrence – only the second time in over 40 years – that it rated its own headline in the BBC News.  Swan divorce.

(photo of Bewick’s Swan showing its distinctively marked bill, by Adrian Pingstone, from Wikipedia in the public domain)

American avocets look so romantic when they court. 

Before they mate they do some ritualistic preening and splashing.  Afterward they dance together.  He puts his wing over her shoulder, they entwine their necks, cross their bills and strut a few steps.  How sweet!

Happy Valentines’ Day

(photo by Kim Steininger)

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)

Today is one of the heaviest travel days in the U.S. so I thought it an appropriate time to tell you that the roads may be congested overhead as well.  That’s because birds sometimes use them for navigation.

This is not a new discovery.  People who race pigeons had noticed that their birds seemed to follow roads – big roads – when racing home.  It wasn’t possible to prove this however until 2004 when GPS tracking technology got small enough to put on the back of a racing pigeon.

They tested the theory near Rome where they released racing pigeons 20-80 km from their lofts.  Researchers found that the experienced birds tended to follow roads and railroad tracks until they were relatively close to home.  If a bird had flown the route before it was much more likely to use a road as a guide.  Some birds even went out of their way to stay on the road and turn only at intersections.

Why do they do this?  Perhaps because it frees up their minds for focusing on other things.

And why do we prefer expressways?  Perhaps for the same reason … except that our minds are very busy today because the traffic is so bad.

For more information click here for the online article.

(photo by Alan D. Wilson www.naturespicsonline.com, in the public domain under the Creative Commons Attribution ShareAlike 2.5 license at Wikimedia)

With so many crows in town it’s inevitable they’ll encounter a predator they don’t like.  Pity the immature Coopers hawk in this picture! 

As a species Coopers hawks have enough moxy to cope with crows but 3 to 1 is stretching the odds. 

I’m sure the crows started it.  A “Coop” is not going to eat a healthy adult crow but the crows remember what the hawk can do to their weak youngsters, so when they found an immature Coopers hawk they decided to test their strength, maybe have a little fun at the hawk’s expense. 

They’re serious about this fight but it’s not life threatening.  Eventually it breaks up, no one gets hurt, and everyone involved learns a valuable lesson. 

The crows learn about cooperation.  The Coopers hawk learns to avoid gangs.

(photo by Steve Gosser, September 2008)

I can answer that.  Almost no one.

Since midsummer we’ve lost more than five hours of sunlight so there’s not much reason to sing.  The migrant songbirds have left and only our locals (chickadees and cardinals) and some winter visitors (dark-eyed juncoes) remain.  Most of them have nothing to say.

My only hope for birdsong is at dawn and the singer is the bird pictured here - the Carolina wren.

According to the range maps, Carolina wrens don’t migrate but I wonder if they change territories in the winter.  What explains the new scuffles and song duels they engaged in in October?  Why does each wren now sing briefly at dawn? 

I hear them pipe up one after the other.  “I’m here,” says the wren down the street.  “I’m here,” says another across the ballpark.  “I’m here,” says a third up the hill.  After this brief exchange of greetings they fall silent. 

You have to be out early to hear birdsong this month.

(photo by Marcy Cunkelman)

Why is this bird in such a hurry to migrate south in mid-summer after raising only one brood in North America? 

The answer is a surprise.  It turns out that some yellow-billed cuckoos raise a second family in the thorn forests of western Mexico.  And so do orchard orioles, hooded orioles, yellow-breasted chats and Cassin’s vireos.

Called “migratory double breeding” the discovery was stunning.  Scientists knew of just two Old World species who did this on their journey north but no birds had been found to do it in the western hemisphere and none anywhere were known to double-breed on the southbound trip.

Gathering the evidence was truly detective work.  Scientists were in the thorn forests in July and August, expecting to study the molt cycles of migratory songbirds.  Instead they found males singing on territory, female birds with established brood patches and no young birds as they’d expect if the families had already bred in the forest.  The clincher was when they found the nests and eggs.

If five songbird species are double-breeding in the thorn forest, why did it take so long to discover it?  July and August are forbidding months in western Mexico.  It’s the monsoon season with temperatures at 100 degrees, humidity at 100% and lots of biting insects.  People have only recently begun to farm the region, leading to a decline in thorn forest habitat.  Interestingly, the habitat decline coupled with migratory double-breeding may explain the decline of yellow-billed cuckoos in the western U.S.

So like the story of a man who has two families half a continent apart, these birds must hurry to squeeze in a second family in western Mexico, then finish their migration to tropical Central and South America.  That’s what the rush is all about.

Read more about the discovery in this Science Daily article.

(photo by Chuck Tague)

What was this downy woodpecker doing before she got nervous about having her picture taken?  She was eating those whitish berries.

What are those whitish berries?  Poison ivy!

This fall there’s a good crop of poison ivy berries in western Pennsylvania and the birds are loving it.  I’ve seen large flocks of migrants hopping among the vines and eating the berries.  I’m always amazed they do this.  Touching poison ivy causes a nasty rash for most people.  Eating the berries would be devastating, even life threatening. 

I have heard that some people think you can desensitize yourself to poison ivy by eating small amounts and gradually increasing the dose.  Would you want to be the one to try? 

Now that the leaves have fallen it’s harder to recognize poison ivy so be careful not to collect these vines and berries for decorations.  Look, but don’t touch!

(photo by Chuck Tague)