Bird of the Week: Yellow-Rumped Warbler

Yellow-rumped Warbler
Setophaga coronata
Crowned moth-eater

Winter weather here in Central Texas brings unpredictable weather, predictable allergies and splashes of yellow in the trees. The Yellow-rumped Warblers, still known to some by their more common name “butter butts”, swoop into the Hill Country in the fall and stay through April when they migrate northward. These warblers winter across most of central and southeastern U.S.

In winter, their colors are a more subdued brown with pops of yellow on the face, sides and rump. After their spring molt, their plumage matches the splashes of flowers with a brighter yellow, jet black and white.

Adult males also have a patch of yellow on their crown. The scientific name Setophaga coronata roughly translates to crowned moth-eater.

The most common and numerous wintering warbler in the US, the Yellow-rumped warbler can be seen quickly moving and sharply chirping in the shrubs and trees. They often forage in small groups known as a “bouquet”, “wrench” or “confusion” of warblers. The bouquet of warblers may forage alongside titmice, chickadees and kinglets.

Illustration by Mark Catesby circa 1729 for his book The Natural History of Carolina, Florida and the Bahama Islands.               

The painting above shows a dead Yellow-rumped Warbler hanging by a string tied to a rosebud orchid. This painting was used in the aforementioned book published in 1729. To paint the bubbly bird in such a way is thought, then and now, to be an odd choice by Catesby.

The Yellow-rumped warbler has a distinct survival advantage in foraging. Not only do they feast on insects, but in fall they switch to berries including the bayberry and wax myrtle berry. The Yellow-rumps are the only warblers with the ability to digest those two berries.

During courtship, the male will follow the female incessantly, fluffing his side feathers, raising his wings and his yellow crown feathers. He will call and flutter all while accompanying the female everywhere.  The female usually lays 4 greenish to cream-white eggs. She incubates them for 12-13 days, and the young birds will leave the nest at 10-14 days after hatching. Both parents feed nestlings. A pair may attempt more than 1 brood per year. According to the Texas Orinthological Society Handbook of Birds (2004), Brown-headed Cowbirds, may parasitize as many as 31% of nests.

The Yellow-rumped Warbler has two distinct subspecies that used to be considered separate species: the “Myrtle” Warbler of the eastern U.S. and Canada’s boreal forest, and “Audubon’s” Warbler of the mountainous West. The Audubon’s has a yellow throat; in the Myrtle subspecies the throat is white. Male “Audubon’s” Warblers have more white in the wing than the “Myrtle” Warbler. Female Audubon’s have less distinctly marked faces, lacking the dark ear patches of the “Myrtle” Warbler. Both male and female Audubon have a pronounced yellow patch on their crown.

To bring butter butts to your backyard, offer sunflower seed, raisins, suet or peanut butter.

Written and comprised by Lindsey Hernandez

Public domain photo//Photos by Rhododendtrites

Sources include All About Birds, Texas A&M’s Texas Breeding Bird Atlas, and Audubon Field Guide