The Yellow-rumped Warbler (YRWA) is one of the most widespread and abundant warblers in North America. It’s known for its versatility in habitat, diet, and migration, and is one of the few warblers that remain in much of the U.S. during winter.

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Identification

Size: Small songbird; 4.7–5.5 inches (12–14 cm) in length

Wingspan: 7.5–9.1 inches (19–23 cm)

Weight: 11–14 grams

Shape: Typical warbler—slim with a short, thin bill and a relatively long tail

Plumage

Breeding Male: Gray with black streaks Bright yellow patches on the rump, sides, and crown Black mask and throat (especially in the Myrtle form) White wing bars

Female: Duller than males; still show yellow rump and some yellow on the sides

Nonbreeding Plumage: Brownish overall but still has the signature yellow rump—nicknamed “butterbutt”

Juveniles: Mottled brown, resembling winter adults

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Range & Habitat

Breeding Habitat: Coniferous and mixed forests Boreal forests (Myrtle) Montane forests (Audubon’s)

Winter Habitat: Open woods, brushy areas, parks, and gardens One of the few warblers found regularly in the U.S. during winter

Migration: Highly migratory Winters in the southern U.S., Mexico, Central America, and the Caribbean

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Diet

Primarily insectivorous during breeding season: caterpillars, beetles, ants, and other small insects

In winter, they switch to fruit and waxy berries, such as: Bayberry Wax myrtle Juniper Poison ivy berries.

Their unique ability to digest waxy berries allows them to winter farther north than most warblers.

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Behavior

Feeding: Active foragers, often flitting through tree branches or sallying out to catch insects midair

Social: Can be seen in mixed-species flocks during migration and winter

Vocalizations: Song: A soft, sweet trill or warble Call: A sharp “check” or “chip”

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Breeding

Nesting: Nest is a cup-shaped structure made of grass, twigs, moss, and lined with feathers

Placed on horizontal branches of coniferous trees, often high up Clutch Size: 4–5 eggs

Incubation: 12–13 days, mostly by the female

Fledging: Young leave the nest about 10–14 days after hatching

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Conservation Status

IUCN Red List: Least Concern Populations are stable or slightly declining

Benefited from reforestation and suburban plantings of berry-producing shrubs

Commonly seen during migration due to wide range and numbers

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Fun Facts

The nickname “butterbutt” comes from the conspicuous yellow patch on their rump.

They are often among the earliest warblers to return in spring and the latest to leave in fall. They’re one of the few warbler species that can survive cold snaps by eating berries.