The yellow warbler found in the Galapagos Islands is classified as a subspecies of *Setophaga petechia*, which also includes a population on Cocos Island, Costa Rica. This bird is a relatively recent addition to the archipelago, having arrived less than 300,000 years ago. True to its name, the yellow warbler is bright yellow in color. Males sport a red cap and red streaks on their chests during the breeding season, while females may have either faint or no streaks at all. Juveniles typically display duller colors. Yellow warblers are monogamous. The female builds a small cup-shaped nest in a tree and primarily incubates the eggs and cares for the young, while the male usually guards the nest and brings food. They typically lay two to five eggs, which take about ten days to hatch. These birds primarily feed on insects such as midges, caterpillars, and beetles, catching them in short flights like flycatchers or foraging on the ground and in trees.