Woodland Birds, Pacific Northwest
Recently, while hiking along the Quinsam River just northwest of Campbell river, i noticed a small, slate gray bird in the middle of the river. With wild abandonment, it would leap into the frothy, rushing current of the river, submerge for longer than seemed possible. Then with a sudden splash, would pop up, fly onto a boulder, and gobble an insect it had grabbed underwater. Then the bird would tip its head back and sing. This is the american dipper.
All of the coastal rivers and streams of BC have dippers nesting there. The american dipper is chunky, gray colored, with a dark bill, and is up to 20 cm long. It has long legs, a stubby tail, and short strong wings. White eyelids flash when the bird blinks. The male and female look alike, but the juvenile is a little lighter in color.
The wren shaped dipper gets its name from its strange movements. The bird bounces its body up and down, sometimes also twitching its wings. Theories vary as to why dippers dip. Some experts say the movement helps the birds communicate with their mates; others say it scares off potential predators. I don’t know why they do it, but it is awesome to watch.
Both male and female dippers sing year round. The song is usually a long series of trills and warbles, loud enough to be heard above the roar of a mountain stream. The birds sing to stake out their territories and to attract a mate.
American dippers forage for aquatic insects and their larvae, small fish, and fish eggs. They wade in shallow water, using their strong claws to grasp rocks in the stream bed. If the water is too deep for wading, the dipper swims, using its feet to paddle and its strong little wings to help propel it against swift currents. During insect hatches, the dipper will take to flight and skim just above the water, snatching insects on the fly.
Dippers have the greatest oxygen capacity of any songbird. They have nasal flaps to keep water out of their nostrils, helping them remain underwater for up to 30 seconds. They have a thick coat of down beneath a heavy layer of waterproof contour feathers which provides insulation from even the coldest waters. A dipper preens extensively, spreading the oils that maintain the water proofing and smoothing feathers to protect the down beneath with its insulating qualities.
Dippers use fast flowing water to protect their nests, which they build in the most unlikely places—below bridges, into steep creek banks, and even behind waterfalls. The nests, which have an opening on the side, are constructed of grass and leaves and are covered with a layer of moss. The female builds the nest, although sometimes the male might help. The same nest may be used for years as the male and female rejoin there each spring.
Dippers lay up to 5 white eggs, which take about 15 days to hatch. While the babies stay in the nest for about 24 days, the male helps the female with feeding duties. When the babies leave the nest, they are able to swim and dive. Dippers sometimes will have 2 broods a year.
American dippers breed in the western mountains near streams that have clean, flowing water. Except during the breeding season, the birds are solitary. Migration is often limited to within a single water drainage.