Natural History: The Brown-headed Cowbird feeds on insects and other invertebrates, as well as seeds and grains. It often takes cover in dense foliage, but also is seen resting on telephone poles and lines. This bird lays its eggs in the nests of other species, especially warblers, finches, flycatchers, and vireos and displaces the young of those species. Breeding season runs from March to August.
General Distribution: In the Presidio, this species is found in all habitat areas. It is a nest parasite in the Presidio that is becoming increasingly common.
Frequency: This species is common to abundant in all seasons except winter.
Identifying Characteristics: Males are iridescence black with a brown head and dark eyes. Females tend to be grayish-brown with weekly striped breast.