Missing something

Red-bellied Woodpecker juvenile

Is it the angle of this shot or does this juvenile Red-bellied Woodpecker seem to be missing something? Its tail.

Red-bellied Woodpecker juvenile and House Finch

Yes, definitely missing its tail, as well as the signature red feathers on the crown and nape of its neck.  But the latter is typical of juveniles, the former (tail loss) is a liability.

Some predator may have tried to grab the youngster by its tail and pulled the feathers out. Normally, wing and tail feathers would develop simultaneously in young birds, so a fully feathered wing and absence of tail indicates some foul play here.

Woodpecker tails form the third leg of a tripod with their feet to support them on vertical surfaces, as the photo below illustrates.  The central tail feathers are pointed and especially stiff, propping the bird up while holding the body away from the tree surface.

Red-bellied Woodpecker illustrating the tripod of support provided by two legs and stiffened tail feathers

Woodpeckers typically spread their tail feathers as they land on a vertical surface, increasing the surface area of that third leg.  The central quill (rachis) must be strong enough to function as a support but must also flex and not bend, like a drinking straw would. This is accomplished by increasing the diameter of the central tail feather rachis, filling it with a high density of interlocking keratin proteins surrounded by a rigid keratin shell.

hairy woodpecker tail cross section-from http://ocw.mit.edu/courses/materials-science-and-engineering/3-a26-freshman-seminar-the-nature-of-engineering-fall-2005/projects/wp_tail_feathev1.pdf

Cross sections of the central quill (rachis) of body and tail feathers of a Hairy Woodpecker illustrate well the strengthening provided by higher density of keratin in the shaft of the tail feather.  From a presentation by Tiffany Lee (MIT open courseware).

Without its tail support, young RBW will find it difficult to forage for grubs under the tree bark.  Perhaps that’s why it has been a constant visitor at the birdseed feeders recently.

8 thoughts on “Missing something

    • Not very many, at least by comparison with the number of babies in your backyard. And I don’t often see the youngsters at the bird feeders for some reason. I must not be putting out the right stuff.

  1. Hmm… I wonder how long it will take for him to grow his tail feathers and what the chances are he will survive long enough to grow the feathers? Interesting post!

    • Well, at least a couple of weeks I would imagine. The bird probably still gets some of his nutrition from his parents, so it will probably survive.

  2. Oh no, poor little guy. That is a serious liability. Perhaps his parents are still keeping an eye on him – or I’m guilty of wishful thinking.

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