Yellow-rumped Warbler

The Yellow-rumped Warbler (Setophaga coronata) is one of North America's most common and widespread songbirds. Famously hardy, it is often the first warbler to arrive in the spring and the last to leave in the autumn. This species is divided into two distinct, regional forms that were once considered separate species: the eastern "Myrtle" Warbler and the western "Audubon’s" Warbler.

While highly insectivorous during the spring and summer, the Yellow-rumped Warbler possesses a unique digestive adaptation that allows it to digest the waxy coating of bayberry and waxmyrtle berries. This dietary flexibility enables them to winter much further north than almost any other warbler species, making them a familiar sight in parks, backyard gardens, and coastal dunes throughout the colder months.

Identifying a Yellow-rumped Warbler is made easier by its namesake field mark, though variations between seasons and geographic forms require a keen eye.

Key Field Marks

• The "Butterbutt": Both forms, in all plumages and sexes, exhibit a bright, lemon-yellow patch on the rump, which is highly conspicuous when the bird is in flight.
• Breeding Males: Striking blue-gray above with a black breast, white belly, and bold yellow patches on the sides of the breast (flanks) and the crown of the head.
• Non-breeding/Winter Plumage: Dull brownish-gray overall, but still retaining the bright yellow rump and faint yellow wash on the flanks.

Form Comparisons

• Myrtle Warbler (North and East): Features a crisp white throat that wraps around the side of the neck behind a dark cheek patch, and a distinct white eyebrow line (supercilium).
• Audubon's Warbler (West): Features a distinct yellow throat, a more uniform gray face with a broken white eye-ring, and lacks the bold white eyebrow.

Similar Species

• Magnolia Warbler: Also has a yellow rump, but is much yellower overall beneath with heavy black streaking and has a distinctive white band across the middle of the tail.
• Palm Warbler: Frequently pumps its tail and has a bright yellow undertail covert, but lacks the distinct yellow rump and side patches of the Yellow-rumped Warbler.

During the breeding season, Yellow-rumped Warblers inhabit mature coniferous and mixed forests, particularly those featuring spruce, fir, pine, hemlock, and birch.

In migration and winter, they utilize a vast array of habitats including open oak forests, backyard gardens, agricultural edges, shrubby fields, and coastal dunes where bayberries are present.

Range and Migration

• Breeding Range: Spans from Alaska across the boreal forests of Canada, down into the northeastern United States, and south along the Western mountain chains (Rockies and Cascades) into Mexico.
• Wintering Range: Covers much of the southern and coastal United States, extending south through Mexico, Central America, and the Caribbean.

Foraging and Diet

Yellow-rumped Warblers are incredibly active foragers. Unlike many warblers that stay hidden in the high canopy, they regularly flycatch—sallying out from outer branches to snatch insects from mid-air much like a tyrant flycatcher. They also search for insects on tree trunks, hop along the ground, and cling to winter berry clusters.

Vocalizations

• Call: A very distinct, loud, dry metallic check or chip. Learning this call is one of the easiest ways to detect their presence in winter and during migration.
• Song: A slow, soft, warbling trill. The Myrtle form's song typically rises or falls slightly at the end, sounding like tuwee-tuwee-tuwee_ti-ti-ti, while the Audubon's song is a more uniform, flat trill.

Nesting

Nests are built primarily by the female, usually placed on a horizontal branch of a conifer, 5 to 50 feet off the ground. The cup-shaped nest is constructed from twigs, pine needles, moss, and bark, and is famously lined with soft feathers. The female typically lays 4 to 5 eggs which hatch in about 12 to 13 days.