The Brown-headed Cowbird is a common breeder throughout the state. Trend estimates indicate that this species has declined during the past nine years; however, the BCN Survey does not adequately survey agricultural areas. Cowbirds are also very nomadic and travel in flocks even during the breeding season which can make year to year trends difficult to estimate. The Brown-headed Cowbird does not build its own nest. Instead, it lays its eggs in the nests of other species - a process known as brood parasitism. Photo: © Norman Bateman