Chestnut-sided warbler, breeding male, location unknown, May 2017. Andy Reago and Chrissy McClarren, courtesy of Wikimedia Commons.

Chestnut-Sided Warbler, female, location unknown, September 2018. Andy Reago and Chrissy McClarren, courtesy of Wikimedia Commons.

chestnut-sided warbler

Setophaga pensylvanica

Identification: 
This small bird has different guises depending on sex and season. Breeding males have a bright greenish cap, white breast, and chestnut colored streaks on the sides.  Females in breeding season are paler versions of the male.  Nonbreeding femals have the same bright cap and plain front, but no chestnut coloring.  All versions have two prominent wingbars.

Behavior:
This foliage-gleaning insect-eater prefers scrubby successional habitat. It mainly subsists on insects and other invertebrates. It nests in shrubs fairly close to the ground, often in a crotch. 

What brings it to the SBG?
Food, cover, nesting sites. Pennsylvania is within this bird’s breeding range, and the SBG supplies abundance of its favorite food, insects, and shrubby habitat for nesting. This bird has fared well as Eastern forests were cleared and began to regrow.

When can I see it?
Spring, summer, and fall.  In winter it migrates to Central America.