Sunday, January 6, 2013

A little creeper in our backyard...

Our recent snows brought a new visitor to our backyard...a Brown Creeper (Certhia americana)! This cute mouse-like brown bird landed at the base of our half-dead weeping willow tree when I was standing about 20 feet away photographing Dark-eyed Juncos (click here for those shots). He efficiently and thoroughly worked his way up the tree, turning over loose bark and peering into crevices as he hunted out spiders and other overwintering insects and eggs. When he exhausted the willow tree, he flew over to the ash tree and worked his way up it...

Brown Creeper (Certhia americana) climbing up a Weeping Willow Tree in our backyard.
A Brown Creeper clings to the bark on the weeping willow tree in our back yard.

Brown Creeper (Certhia americana) using its tail as a prop.
I noticed the Brown Creeper was using his tail as a prop, much like a woodpecker does. 

That's a mighty fine pygostyle you've got there...
I recently read in the book Wild Bird Guides: Downy Woodpecker by Gary Ritchison, that the anatomical structure that allows woodpeckers to use their tails as props is called a "pygostyle." A cool name that stuck with me, because when I saw the Brown Creeper using its tail in the same posture, "pygostyle" popped in my head, and I wondered if a Brown Creeper's pygostyle was similar to a woodpecker's. After looking in a few books and doing a few Internet searches, I found it was.

How is it different?
The pygostyle in a bird is made from 4-10 fused posterior caudal vertebrae...basically, it's the bird's tail bone (like our coccyx). The pygostyle and the muscles around it give support to the tail feathers (rectrices), and while all birds have a pygostyle, not all pygostyles are the same. For example, the bones in a woodpecker's and creeper's pygostyle are much larger and the muscles surrounding it are much stronger than those in an average bird's tail. Most birds fly and perch on branches, but woodpeckers and creepers cling to and walk up the vertical surface of a tree trunk. Their tails help them stay in place because they work like a prop. Additionally, these types of birds have the adaptation of very stiff tail feathers, especially the middle feathers...all the better to lean on when clinging to or walking up a tree trunk. If you look closely, the middle feathers are also pointed and curve slightly inward to guarantee the tail makes solid contact with the bark (Ritchison, pg. 10).

Other birds have well-developed pygostyles too, for example, woodland hawks that use their tail feathers for precise steering through branches have well-developed pygostyles, and birds that use their tails for upward lift to help them hover, such as kestrels, do too.  If you'd like to see a labeled bird skeleton of the pygostyle, click here and look at #2. (However, if you've ever dressed a turkey or a chicken, you've already seen the pygostyle! It's the "Pope's nose" or the "parson's nose," the colloquialisms for the fleshy triangle at the tail.)

Brown Creeper (Certhia americana) checks out an abandoned woodpeckers hole.
While spiraling up the tree, our little Brown Creeper popped into an exposed and abandoned woodpecker's hole for a few seconds before continuing on. It's unusual to see a Brown Creeper standing out so well. Usually their camouflaging colors and patterns make them invisible against the bark. They are no match for the inside of a tree!

Brown Creeper using its tail to help it stay on the tree.
It's easy to see how the Brown Creeper makes good use of its tail. The pointed tail feathers are stiff like a Downy Woodpecker's and when combined with the strength of a well-developed pygostyle and muscles it becomes a very good prop and helps the bird cling to the tree trunk's vertical surface. 

This little brown bird is often hard to spot, and is often described as being a small piece of moving bark!
It's always fun to spot a Brown Creeper. They blend into the bark so well sometimes it's hard to see them. I usually hear their ultra-fine peeping and then watch until I see a little movement. Their habit of spiraling up a tree and then diving down to the base of the next tree helps a little when looking for one. 

...just like woodpeckers, this bird has evolved a well-developed pygostyle, stiff tail feathers, and inward curving tail feathers to help it cling to vertical surfaces.
...here you can see the inward curve on the Brown Creeper's middle tail feathers. 

Closeup of the extra-long hind claw or back toe nail on a Brown Creeper.
...another adaptation, Brown Creepers have extra long back toe nails, or hind claws, to help them hook into the bark. 

p.s.
The snow blew in another backyard favorite, our American Tree Sparrows (Spizella arborea)! Every year I wait for them to show up, but they never seem to arrive until snow or a severe cold snap moves in. I saw two on Wednesday....exciting. I love the tinkling, sweet calls of a flock of American Tree Sparrows.  This afternoon Rick and I went to Armleder Park to look for longspurs, we didn't see those, but we did see and hear hundreds of American Tree Sparrows...what a magical sound!
Click here for an older post on American Tree Sparrows--a favorite winter visitor.

27 comments:

  1. I love your "Brown" Creeper, we call it a Treecreeper. Isn't it fantastic, brilliant photos you took.

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  2. Difficult bird to take pictures .. Congratulations and best regards ..

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  3. You got some AWESOME shots .... and I always get an education when I stop by! Thanks!!

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  4. What a darling little bird. Your images are excellent as always. Beautiful series.

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  5. wonderful images - we see tree creepers around here but not got any on camera yet! Thanks for sharing

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  6. Nice catch, Kelly! They blend in so well that I've never been able to get a decent shot of one.

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  7. Lovely photos Kelly. We have the Treecreeper here and they are never easy to photograph. I have never had one in my garden although my friend who lives quite near has!

    Wishing you a very Happy New Year :-)

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  8. I have seen a brown creeper only a couple times in my life! Your photos of him are superb (as always!)

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  9. Excellent set of shots Kelly.
    Just like our Treecreeper here.

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  10. you got some wonderful shots of this quick, elusive bird! beautiful job!

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  11. Brown creepers and nuthatches. I love these little scavengers.

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  12. Hi Kelly ...How ironic..I just saw on this morning on the tree in back of the house..I know they are around, but seem to be shy , usually just hear them !!
    Great photos and great information ..such a cutie!!
    Grace

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  13. You got some great pictures of that little Creeper. They usually move up the tree so fast that by the time I have found them in the viewfinder, they are gone.

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  14. You achieved some really good shots of this normally uncooperative little bird Kelly.{:))

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  15. I love creepers. They're fairly regular visitors here along the riverbank…but quick and nearly constant in their movements up and down the trunks, making them tough to photograph. You did an amazing job. Great info, too.

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  16. Fabulous post filled with interesting information and wonderful photographs! I learned something new today from reading your terrific post. These busy little birds are so much fun to watch. I did not realize they have such a long hindclaw. Cool!

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  17. I saw this bird for the first time this year. He comes to the same oak tree. I haven't been able to take even one photo though. Congrats on your great photos.

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  18. Outstanding shots! I can only find them if I catch their movement. Ever notice how their plumage looks blurred, even when they are still? Very nice!

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  19. Love the pictures of the creeper, so well camophlaged. Thanks for the info on this little bird.

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  20. Most interesting post. These handsome little brown birds always look so busy as they pursue their business spiraling up the tree....

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  21. Awesome photos and post on the Brown Creeper!

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  22. Great photos and info, Kelly! I marvel at Creeper's tail - never realized it was so long!

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  23. ...thanks, everyone, for dropping by and leaving your kind words! What cuties these birds are, but they are hard to photograph. Like you've mentioned in your comments, they are so quick and slip on the other side of the tree so easily! I haven't seen him back in the yard since the snow left. I hope he returns!

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  24. Great photos and wonderful write-up! I definitely learned something new from reading it :-)

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