Rigor Vitae: Life Unyielding

Wednesday, June 14, 2006


The roads were dangerous yesterday. A few hours after my unplanned diversion in a bank parking lot, I passed a freshly-killed woodpecker on 7th East, one of Salt Lake's major thoroughfares. I was heard to shout "Yellow-shafted!" as I applied my brakes. The bird lay on its back, its long tongue protruding, as that of any self-respecting roadkill should be. Woodpeckers use their elastic tongues to probe cavities and retrieve wood-boring insects. The organ is anchored to the Y-shaped hyoid bone, which floats in the throat--as it is in most tetrapods. The two proximal ends of the tongue, however, continue past the legs of the hyoid, wrap around either side of the back of the head, and are finally anchored in one nostril (the bird breathes through the other one).The tongues of the unrelated hummingbirds (family Trochilidae) wrap around the skull in precisely the same manner. Having a long tongue is an advantage for animals that use it to forage, but storing the thing when it's not in use without impeding breathing and swallowing becomes a problem. The tongues of chameleons (family Chamaeleonidae) are bunched up like a sweater sleeve on the hyoid bone by longitudinal muscles running down their center. The tongue is expelled by rows of sphincter muscles that surround the interior longitudinal ones. The tongues of the New World nectar-feeding bats of the subfamily Glossophaginae (family Phyllostomidae) are extended not only by muscles, but by blood engorgement. The most amazing tongues of all belong to the Old World pangolins (order Pholidota), whose termite-trapping tongues run the length of their bodies, and are anchored to the pelvis.
Back to the woodpecker, though. It's the yellow-shafted form of a Northern Flicker (Colaptes auratus). Two centuries ago, the American Great Plains formed a treeless barrier that was impossible for many species to penetrate. As the Great Plains became the Grain Belt, trees were planted throughout the region, and many American birds extended their distribution inland; some of them merging with relatives from the other side of the continent and hybridizing where their ranges met. Among these merging species were Audubon's Warbler (Dendroica auduboni) of the western U.S., and the widespread, white-throated Myrtle Warbler (D. coronata) of Canada and the eastern U.S. The former is now considered a subspecies of the latter. The Western Bullock's Oriole (Icterus bullockii) was similarly merged with the eastern Baltimore Oriole (I. galbula), but recent DNA analysis has determined that the two are less closely related than was previously assumed. Our western Red-shafted Flicker (Colaptes cafer) met the same fate, and is now considered but a race of C. auratus. Intermediate forms of the eastern and western flickers are supposedly common in the midwest, and yellow-shafted birds are increasingly showing up out here, but this male bird was the first one I've ever seen in Utah. It would have been much nicer to see those lemon-yellow wings in flight. Speaking of which, I was struck by the extreme feather wear on this bird. A terminal inch or two of his primaries were worn away, and his tail feathers were similarly hammered. I assume this was caused by moving around inside of tree cavities. Both sexes excavate cavities, and share incubation duties as well, so I wouldn't expect to see much sexual differentiation in feather wear. Flickers normally sleep in tree cavities the year round, but I've never seen this kind of wear before in my limited experience with woodpeckers.
upper: MELLER'S CHAMELEON & LEAF-TOED GECKO (1993) Acrylic 20" x 26"
lower: Photograph of Yellow-shafted Flicker taken by CPBvK in Salt Lake City, June 13, 2006


Anonymous Anonymous said...

I like the caption you chose for the photo: flickersplat :)

3:12 PM  
Blogger Carel Brest van Kempen said...

I'm glad to have found him before that caption became really appropriate.

10:33 PM  

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