Bird of the Week

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    Photo courtesy Charles Martinez

    This week’s Bird of the Week, compliments of the Weminuche Audubon Society and Audubon Rockies, is the Brewer’s blackbird. 

    Though the males are commonly mistaken for other species, such as the common grackle or the brown-headed cowbird, once you’ve witnessed the signature “loafing” behavior of this species and committed its plumage to mind, it’s a hard one to forget. These birds are often seen in fairly visible locations bobbing their heads up and down as they hunt for insects on the ground in summer or scan for grains in winter. Though not particularly adept at perching, these birds will come to feeders, but often prefer to ground forage and glean scattered seed. 

    Males are a site to behold in full sun, as their iridescent plumage is stunning, simultaneously flashing a glossy green and even metallic purple-black (especially in the head). Like a common grackle male, their eyes are a piercing golden-yellow color, but Brewer’s blackbirds have a much smaller and straighter bill and definitively round head. Remember, male cowbirds have a brownish head and lack the yellow eye. Females can be trickier, if seen without their male counterparts. They are a flat brown throughout with darker wings; round tail; and darker, almost reddish eye. Juveniles present as gradations between male and female plumages. In breeding season, males will point their bills straight into the air and strut with feathers ruffled to impress and woo mates. These birds build their nests of small stems, mud and manure in vegetation (shrubs and trees) near water. Like other blackbird species, Brewer’s blackbirds often nest in colonies. Mating songs are typically more rudimentary than red-winged blackbirds, but retain the metallic quality and volume of their cousins. More typical are their single-note “tchup” or “chuk” alarm calls.

    A visible year-round resident of rangelands and even townships in southwest Colorado, this bird is named after the renowned ornithologist Thomas Mayo Brewer, a peer of John James Audubon and co-author of “A History of North American Birds” released in 1874. Though Brewer’s blackbirds have in many cases benefited from agricultural practices through additional food sources, their Continental Concern Score, as per the 2014 State of the Birds Report is a nine out of 20, signaling a sharp decline in numbers over the last century. Historically incorrectly viewed as crop pests, these birds in fact offer the farmer a great means of insect control and should be heralded for their environmental services. 

    For information on activities, visit www.weminucheaudubon.org and www.facebook.com/weminucheaudubon/.