Much beauty disappears from Oregon in winter.

Male western tanagers, stunning mosaics of orange, yellow, black and white in the breeding season, molt into more somber colors and depart for sunny Mexico. The same goes for the bright turquoise lazuli buntings.

Some of the showy breeding birds remain, but like the tanager, they change to dull grays and browns. Yellow-rumped warblers would be nearly invisible if not for the yellow rump patch. Many birders are familiar with the common name for them in the eastern United States of “butter butt” for this reason.

As spring approaches, males transform into a patchwork of bright yellow, black and white. American goldfinches become almost unrecognizable as they lose the canary yellow and black breeding plumage in exchange for browns and the lightest golden wash.

There is one species that winters sparsely in the Rogue Valley that will brighten any winter day, the Townsend’s warbler. While some warblers go incognito in winter, the Townsend’s warbler retains its bright breeding plumage year-round.

Why some warblers retain their breeding plumage, but others do not is an interesting question. It may be that living among dense conifer foliage, Townsend’s warblers are concealed sufficiently that they don’t pay a penalty for potentially being highly visible to predators.

I maintain it is the most beautiful warbler. It is boldly patterned in black combined with the brightest yellow on its face and breast. White wing bars and tail spots provide accent. It is a close relative of our hermit warbler. Easterners extol the beauty of the male blackburnian warbler, and I don’t disagree, but it doesn’t quite match up with the Townsend’s warbler, in my opinion.

Townsend’s warblers breed in the western mountains from central Oregon and Montana north into Alaska. Most retreat to Mexico and central America in winter, but not all.

A modest population winters along the Oregon and northern California coast. You can sometimes encounter flocks of up to 30 individuals. A small number winter inland to the base of the Cascades, including the Rogue Valley.

A detailed study of wing and tail length, plus other measures, provides insight into the origins of birds that winter in Oregon. While birds breeding in the Rocky Mountains and other inland localities head to the land of margaritas for the winter, our birds appear to have a coastal origin.

More specifically, research suggests most birds that winter in Oregon breed in the Queen Charlotte Islands of British Columbia. Given the number of birds found along the Pacific Coast, I suspect their numbers are augmented by others originating in nearby coastal areas.

If you live in a neighborhood with at least a modest number of conifers — mature Douglas firs are best — you might be fortunate to host one or more of these beautiful birds through the winter. They are particularly partial to suet blocks and will even visit hummingbird feeders if the openings are large enough to permit access.

Stewart Janes is a retired biology professor at Southern Oregon University. He can be reached at janes@sou.edu.