Bird of the Week

This week’s Bird of the Week, compliments of the Weminuche Audubon Society and Audubon Rockies, is the Brewer’s blackbird. This is one of the dark-colored birds whose identity can be confused that we commonly find here in summer. The medium-sized male Brewer’s blackbird when seen in sunlight exhibits an iridescent combination of black, midnight blue and metallic green colors. His yellow eyes are piercing and his bill is straight and dark. European starlings can also appear iridescent in summer, but have yellow beaks and dark eyes. More frequently, Brewer’s males here are confused with the glossy, larger common grackle that also has a yellow eye, but has a longer tail and heavier bill. Brewer’s blackbirds are common in western urban and rural open habitats. On long legs, they walk across the ground with jerky back-and-forth head movements. They may ride the backs of livestock to pick off bugs and wade in shallow water. In summer they consume lots of insects, including those considered agricultural pests, but most of the year seeds and grains sustain them. During the breeding season, they utilize a variety of sites, often near water, for nesting. They will build a nest in treetops, low shrubs, cattails, on the ground or in a tree cavity. Three requirements of nesting habitat that must be met are: suitable nest sites, guard perches for the males and short grass foraging opportunities nearby. Like barn swallows, Brewer’s blackbirds are fierce nest protectors that will dive-bomb people who get too close to the nest. Males watch over nest colonies from guard perches and will harass predators, including owls, gulls and hawks. Camouflaged brownish females lie low on the nest when males sound the alarm. Since the early 1900s, Brewer’s blackbirds have taken advantage of human habitat alterations that have created more open space to expand their range eastward. When they move into territory occupied by common grackles, they displace the grackles from rural habitats, who then move into the cities. Partners in Flight places Brewer’s blackbirds on the list of Common Birds in Steep Decline due to long-term population declines. For information on events, visit www.weminucheaudubon.org and www.facebook.com/weminucheaudubon/.