This week’s Bird of the Week, compliments of the Weminuche Audubon Society and Audubon Rockies, is the merlin.
This is another raptor that we don’t find here in summer. Although we know they are around in winter, where to find one is unpredictable. They are too fast in flight to get a good look, but there have been opportunities to catch one perched on a rock near the river or at the top of a tree. Outside the breeding season, these are generally solitary birds.
Merlins occur accross the Northern Hemisphere. In medieval times, their small size made them the favored birds of lady falconers. In North America, they primarily nest from Alaska across Canada and spend the winter across states from the Pacific to the western Great Plains and along both coasts.
Unlike many birds that are expanding their ranges north, merlins are breeding farther south as they adapt to life in cities. One reason may be related to the increase in cities of crows, whose abandoned nests merlins repurpose for their own. Another may be the number of house sparrows in urban areas.
Merlins are opportunistic hunters, seeking out the most abundant prey, usually small- to medium-sized songbirds. A merlin can consume as many as 900 birds per year. It generally hunts in horizontal flight in surprise attacks by plowing into a flock of birds at speeds near 30 miles per hour. They will also pick off bats leaving their roosts and large insects.
Merlins are not much longer than the more familiar kestrel, but their heavier weight may confer the appearance of a larger bird. They have the typical long, thin wings and long tail associated with falcons, but lack the distinctive mustache markings of the kestrel. They are heavily streaked below. Three recognized North American subspecies show variations in color. Males may be slaty to dark gray on the back, and females and immatures browner.
According to Partners in Flight, between 1970 and 2014 the merlin population in the United States and Canada more than tripled.
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