Friday, February 26, 2016

American Dipper

American Dipper - Cinclus mexicanus

Dippers are a winter visitor to the Elbow River behind my home. After breeding season, the birds often migrate north and to higher elevations to find and feed on aquatic invertebrates. They will winter in locations where the water remains ice-free.

These aquatic birds feed on insects, insect larvae, invertebrates, small fish, and fish eggs.

Dippers can walk and feed underwater. Young dippers can dive and swim before they can fly. The oxygen capacity of the blood in a dipper is higher than non-aquatic songbirds, which allows them to remain submerged for up to 30 seconds while foraging. Dippers have up to twice as many contour feathers compared to songbirds of a similar size and a thick coat of down. These birds need to preen for longer than average to maintain the waterproof and insulation properties of their feathers. The iris sphincter muscles in a dipper are adapted to change the curvature of the lens to facilitate vision both above and below water. 

The dipper has a loud ringing song that can be heard over the low-frequency background noise of streams and waterfalls. 

The photo above shows the white-feathered eyelids of the dipper. 

1. Baircich PJ & Harrison CJO. Nests, Eggs, and Nestlings of North American Birds. Princeton UP, New Jersey. 2005.
2. Sibley DA. The Sibley Guide to Bird Life and Behavior. Alfred A Knopf, New York. 2001.

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