An Excerpt from Jim Conrad's
Naturalist Newsletter of September 25, 2005
issued from California's Sierra Nevada Foothills

BIRDS AT DUSK

About an hour before dusk this week I've been sitting quietly watching the birds. Birding now is a lot different from just a couple of weeks ago because fall migration is taking place all across North America.

During the days, except for the habitual vultures and woodpeckers and an occasional flock of migrating honkers too high to see, birds have been very quiet and secretive. However, an hour before dusk golden sunlight sweeps in over the canyon to the west illuminating the tall Ponderosa Pines around the house. These pines bear big, straight trunks with gnarly, down-pointing lower limbs and the side- lighted trees are widely spaced so it's easy to see birds among them. Having such easy access to so many perfect perches at so many levels seems to make the birds show off, to flit and glide and generally play around with a bit more élan than usual.

An hour before dusk I can't imagine how many Yellow- rumped Warblers might be in the neighborhood. They hop on the ground pecking at this and that, even ants, they work through tree limbs just a few feet off the ground, fly about the garden, and even fill the pines' middle and upper levels -- this after being uncommon or absent at this elevation all summer.

They're in their fall plumage now, which is a lot drabber than their spring and summer outfit. You might enjoy comparing how colorful the male is in spring at http://www.pikespeakphoto.com/warbler.html with how drab the same male looks nowadays at http://www.ventanaws.org/BSOLPhotoPages/phAudubonsWarbler.htm.

Of course the deal is that in spring the male needs to look flashy and sing a vibrant song so he can catch himself a female, but during the fall the main goal for both sexes as they head south is just to eat, keep a low profile and stay out of trouble. Despite these birds' mousy brown and gray, indistinct fall markings, at certain moments when they land with their wings spread out just right, their brightly yellow rumps flash into view for a fraction of a second, and then there's no doubt at all that they're really Yellow-rumped Warblers.

These particular Yellow-rumped Warblers are what old field guides called Audubon's Warblers. Some years ago when it was realized that Audubon's Warblers were freely mating with and hybridizing with the very similar Myrtle Warblers the two species were "lumped" into one taxon and renamed the Yellow-rumped Warbler. It's been hard for me to stop calling our eastern birds "Myrtle Warblers" but after a few decades I've more or less made the change.

During that hour before dusk you can also count on small flocks of bluebirds gliding in from time to time, but they are different from the Eastern Bluebirds for which I built nesting boxes back in Mississippi. These are Western Bluebirds -- SIALIA MEXICANA instead of the East's SIALIA SIALIS. Western Bluebirds are permanent residents here but, still, I haven't seen them this summer, only now. At this time of year there's not much blue to them. Like the warblers, they are drab with indistinct, brownish gray markings.

Woodpeckers also put on a good show each dusk. Most common are the abundant Acorn Woodpeckers with their harlequin face designs, but also there are Yellow- bellied Sapsuckers and one species I almost didn't look at assuming it was the Hairy Woodpecker also present back East. However, this bird had a "ladder design" of slender, alternating black-and-white stripes across its back, where Hairys are white. It was the Nuttall's Woodpecker, PICOIDES NUTTALLII, a specialist of arid to semiarid open woods, and mostly restricted to California and Mexico's northern Baja Peninsula. You can see this bird as well as its map at http://www.birdsource.org/features/nutwoo/.

What a fine time for this daily performance to be taking place, when a fellow with a touch of lumbago can sit quietly and watch.