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)

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)

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 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)

Here’s Dorothy, the adult female peregrine falcon at the University of Pittsburgh, asleep in front of the webcam.  Watching her sleep makes me want to nap, too.

(photo from the National Aviary webcam at University of Pittsburgh)

At last!  After weeks of no rain we’ve had a serious soaking today.  The grass was brown and dormant but today it revived and is showing a bit of green.   

The birds are happy about the rain too.  This morning while I walked to work I saw:

• An adult red-tailed hawk perched on the antenna of Carnegie-Mellon’s Warner Hall.  The red-tail spread its wings in an arc and held its head up as the rain ran down its wings and back.  He was enjoying every minute of his long-awaited bath.
• A flock of house sparrows bathed in a puddle on the sidewalk.  Very splashy and cute!
• Two Cooper’s hawks – an adult and a juvenile – perched next to each other on the fence at our neighborhood ball field.  Cooper’s hawks are notoriously solitary so I assume these two were related.  I thought they were enjoying the rain until I noticed their attention was focused on a flock of five crows walking on the field.  A sixth crow raided the garbage cans below them.  The crows silently eyed the hawks.  The juvenile “Coop” broke the tension by making a low swooping pass at the crows.  The adult Cooper’s hawk waited a bit, then made the same swooping pass.  Then both hawks flew away.  The crows were unfazed and returned to their watery games and garbage feast.

(photo of an adult Coopers hawk by Cris Hamilton)

The gulls wheeled and dipped above the bayside trees.  They were traveling in circles, swooping up, dropping down, zigging left, zagging right.

As I watched them a passerby asked, “What kind of gulls are those and what are they doing?”

They were ring-billed gulls on fall migration from their inland nesting grounds to their coastal winter zone, and they were hawking insects - some kind of flying ants.

I think of gulls as crab and trash eaters so it was fascinating to see them eating flying bugs.  Then I remembered the story of their relatives, the California gulls, in Utah.

The Mormons arrived in Utah in 1847 to establish a religious community near the Great Salt Lake.  Their first crops were nearly ready to harvest the next summer when thousands of “Mormon crickets” (actually a flightless relative of the katydid, Anabrus simplex) swarmed across the countryside.  These insects eat everything in their path – even their fallen comrades – so the Mormons thought their crops would be lost.  But a flock of California gulls arrived and ate the insects.  The Mormons called this the Miracle of the Gulls and named the California gull the state bird of Utah.

Ring-billed gulls haven’t done enough to be named a state bird but I am grateful they eat flying ants.  Now that I know to what to look for, I see them hawking insects every fall in Maine.  The flying ants swarm and the gulls do what comes naturally.  They eat them.

(photo by Chuck Tague)

Someone asked me this question at the bus stop the other day.  I’m not surprised it came up because the ubiquitous city birds - house sparrows – are champions of dust baths.  They’re the ones who prompted the question. 

House sparrows prefer very fine dust and will flap up a storm when they find a patch of it.  They dig a hollow with their feet, push their bellies into the dust and toss it under their wings and over their backs as if it was water.  Their goal is to get the dust into their feathers and all the way down to their skin.  When they’re suitably coated they shake off the dust and preen it away until their feathers are in good condition again. 

Why go to this trouble?  Dust smothers skin and feather parasites and absorbs excess oil that’s removed as the dust is preened away.  Did you know you can clean your hair using powder?  It’s the same idea. 

House sparrows take dust baths even when water is available.  Maybe the first house sparrow came from a desert climate.  After all, their Paleolithic fossils have been found in Ouum-Qatafa Cave in Israel.  If they can clean with dust and save water for drinking, why not? 

This summer we’ve had so much rain the house sparrows must be hard pressed to find any dry dirt.  They might have to use my bird bath after all.

(photo of a house sparrow taking a dust bath by Vishnevskiy Vasily via Shutterstock)

Their feathers wear out so birds molt to replace them.  Robins and cardinals do it once a year.  Long distance migrants molt twice.  American goldfinches molt twice a year but their closest finch relatives don’t.  Who knows why.

Birds replace their feathers in a pattern across their bodies.  Most replace their center two tail feathers, then the two tail feathers next to those and so on until their entire tail has new feathers.  Their wings molt the same one feather at the same time on both wings.  This prevents flight impairment because their wings are still the same on both sides.  Heavy birds, like ducks and geese, molt all at once and are flightless for a short time each year.

I suppose August is as a good time as any to replace their feathers.  April won’t do because they have to look beautiful and sleek during courtship.  Rule out May through July because breeding season is too intense to be hampered by missing feathers.  Winter is too cold which eliminates November through February.  In the other months they’re migrating.  So August it is. 

I’ll be glad when they look normal again.

(photo of a wet northern cardinal by Chuck Tague)

p.s. Have your goldfinches started to turn dull yellow again? Mine have.

There was a radio article on NPR yesterday morning – you may have heard it – in which two eminent crow specialists described how crows recognize humans by their faces. 

Kevin McGowan (Cornell Lab of Ornithology) and John Marzluff (University of Washington) wrote the book on crows – literally, books – and they know what they’re talking about.  They’ve banded and studied more crows than most of us will see in our lifetimes and they soon realized the crows knew exactly who they were no matter what they were wearing.  Marzluff conducted a study to prove it.

I am so impressed!  I was even more impressed when I visited the Morning Edition website, watched the video and took the “Can you recognize a crow by its face?” test.  (I can’t.)  You really must check it out!

And… on the way to finding that article, I found another one about a crow-sized camera that was fitted to New Caledonian crows to record them making and using tools.  My favorite part was, “They caught 18 wild crows and attached the cameras, which weigh less than half an ounce. A timer kept the cameras from filming for a couple days, otherwise they would just record crows trying to tear them off.”  

Of course!  It made me laugh out loud.  

(photo from Shutterstock by Alexander Chelmodeev)