The Wren's Pajamas

Every once in awhile, I get sent a photo like these.

What's that little speckled thing in my planter? I only see it at night.

Thanks to Melissa from DC for this adorable conundrum. Zick loves a conundrum. 

 There are these things that appear on my porch every night. What in the world are they?

Thanks to Sharon from Brunswick for this lovely shot from Maine. A puzzled friend sent it to her, and she sent it to me. Even though she knew what it was.

 Pinecones? Mice? Fair question! Read on. 

 Carolina wrens possess a plumage characteristic that's seldom seen, and even more seldom photographed. I've been trying to catch it with my camera for years, and a cooperative bird on Dean's Fork finally granted me an audience in the warm end of October sun.

When I saw the wren preening, I decided to wait and see what might be revealed.

You can see the gray bases of the bird's back feathers here as it raises them. 

And then, shazzam! the secret Carolina wren polka-dots are suddenly revealed! Do click on the photos for greater detail.

You  never see these white spots on a sleek, moving Carolina wren. The bird has to raise and spread its back and rump feathers on purpose. Only then are they revealed.

Having brought them out, the wren leaves them out. And we can also admire the dots and dashes on the leading edge of its primaries.

I believe that these spangles serve a purpose in camouflaging sleeping birds. Otherwise, why would they sleep with their backs turned to any possible observer? To me, these roosting wrens look like lots of things, most of all pinecones or mushrooms, but not much like birds. And I suspect that's the point of those unexpected spots. Were these birds tucked into a tree cavity or rock crevice instead of a metal awning, they'd simply disappear, become part of the scenery. 

It was a true treat to see a Carolina wren in its pajamas during the day. I'd only seen it once before, on a subzero day when this little one tried to catch some rays in between bites of Zick Dough. 

It's finally nasty here. 40 and raining. Time to make the Zick Dough! 

Now you have seen the Wren's Pajamas. 

About Those Wren Rump Spots

In my last post, I drew attention to the white spangles on the lower back feathers of a Carolina wren, and said I had a Science Chimp theory about them. Any time I see ornamentation on a bird that is hidden from sight when the bird is doing its normal daily routine, I wonder what's going on there. Is there a function to those spangles, one that isn't immediately apparent?

During the ice storm of 2009, the sun broke through only intermittently. This photo was taken on a sub-freezing day, when a wren who had come for some Zick Dough suddenly realized how glorious it felt to have sun on his (or her) back. The bird keeled over in a classic sunning pose, its rump feathers lifted and ruffled, as if trying to soak up maximum rays.

Its mate seems to wonder what's come over it. Honey? You OK?

The wren held this pose for almost a minute, giving me a chance to zoom in on that lovely rump.

The lower back feathers need to be raised and fluffed to reveal the white spangles lying just beneath the brown outer feathers. It really is a lovely effect, but one we all too seldom see. I have seen it, though, on my own porch. At night.

If you saw this on your porch by the light of a flashlight, and you weren't reading a post about Carolina wren rump spangles, would you know what it was?


Neither did the person who sent the picture to my friend Sharon from Maine. Sharon is always getting asked questions about birds. She always knows the answer but likes to check in with the Science Chimp just for fun.

These are roosting Carolina wrens. Awwww. They almost always roost together; they stay as a mated pair year round, and are almost never out of earshot of each other.

My S.C. theory on the rump spangles is that they are meant for camouflage. I'm not sure what they make these sleeping wrens look like, but they don't look much like birds, do they? When I've seen wrens sleeping in the bucket up under my front porch eave, or tucked into a corner in the garage, my first thought is that I'm looking at some kind of small furry mammal. Pretty much the last thing they look like is a defenseless, sleeping bird.

It's not a fully-formed theory, obviously, and I'm open to alternate hypotheses. I just think it's cool to see a small bird utterly transform its shape and appearance while sleeping. And maybe someone out there will look up someday, see a spangly blackish blob up under the porch eave and smile, knowing what it is.