American Dipper
This week’s bird is the American Dipper (Cinclus mexicanus), a bird that may be rather plain looking but is full of pluck (okay, maybe not the best word to use when describing a bird). So named due to its habit of dipping into lakes and streams in search of food, it was formerly called the “Ouzel” (an old English term for blackbird), Water Ouzel, or Water Thrush. While it has some superficial similarities to thrushes, it is in a different biological family called Cinclidae, consisting of 5 species worldwide.
John Muir was so taken by the American Dipper (still known at that time as the Water Ouzel) that he dedicated a complete chapter to it in his book The Mountains of California. Muir described it as “a singularly joyous and lovable little fellow” that you will find “anywhere upon a clear stream … flitting about in the spray, diving in foaming eddies, whirling like a leaf among beaten foambells; ever vigorous and enthusiastic, yet self-contained, and neither seeking nor shunning your company.”
Cinclidae are the only truly aquatic songbirds, and the American Dipper is the only member of this family found in North America. They spend their entire lives near fast-flowing streams, feeding primarily under water that can be frigidly cold from mountain snowmelt. Despite these conditions, they are well adapted with long legs and strong feet to grip stream bottoms, a complete covering of thick feathers leaving no exposed skin, a large oil gland for waterproofing feathers, and a special flap that covers their nostrils when submerged.
What it looks like
The American Dipper is a chunky bird with a body similar in size to that of an American Robin. It is gray all over, with long legs, large head, short neck, and short tail that it often holds straight up like a wren. It has a thin dark bill, and constantly bobs up and down as if its movements will help keep it warm after each chilly water dive. Immatures are similar to adults, but with faint pale barring on the underside. Males and females look similar.
Dippers are quite vocal, with a song Muir described as “the trills of the rapids, the gurgling of margin eddies, the low whispering of level reaches, and the sweet tinkle of separate drops oozing from the ends of mosses and falling into tranquil ponds.” Check it out for yourself.
How it breeds
Dippers are primarily monogamous, with pair bonding lasting for multiple seasons. In some cases, males are polygynous (a male with multiple females), typically in areas with few nest sites available and those that are concentrated in the territory of a single male. The Dipper locates its nest near fast moving water on cliffs ledges, behind waterfalls, under bridges, and on boulders or dirt banks. Females choose the nest site, usually placing it about 6 to 20 feet above deep water to protect it from predators.
Both sexes may help with nest construction, but in some cases only the female builds the nest. Nest construction typically occurs when temperatures are still freezing. The nest is a 2-layered domed or ball-like structure with a side entrance. The outer layer is a thick shell of moss, woven grass, and leaves, while the inner layer consists of grass and leaves. The female lays 4 to 5 eggs and does all of the incubation, lasting 14 to 17 days. The male carries food to the female, but the female also takes a break every hour or two lasting 10 to 20 minutes.
Upon hatching, the young remain in the nest for about 25 days with both parents involved with their feeding. Shortly after they fledge, the young enter nearby water and start with their dipping behavior, gradually gaining strength. They can swim and catch prey about five days after fledging.
What it eats
Their diet consists primarily of aquatic insects and invertebrates, supplemented by small fish they catch and subdue by striking against a rock. They feed almost exclusively in water by walking, swimming, and diving, searching for prey under submerged rocks and debris. They dip their head under water to locate prey, then they will go below the surface by diving, wading, or swimming, staying under water from 5 to 15 seconds at a time. While American Dippers don’t migrate, they may relocate during the winter to find unfrozen streams or lakes. This brief video shows an American Dipper in Marble Canyon, Kootenai National Park, British Columbia.
I observed a pair of American Dippers foraging in an icy river at Rocky Mountain National Park on April 19, 2008. The picture shows one after it emerged from the water holding food, perhaps an aquatic insect, larva, or invertebrate.
Fun Facts
The American Dipper has a very noticeable white eyelid when it blinks. This is often mistaken for a nictitating membrane, something that all birds have that protects the eye while maintaining vision. The term comes from the latin word “nectar” meaning to blink. However, the white eyelid that you see on the American Dipper is a true eyelid covered with tiny white feathers. Nobody knows for sure why it sports such a distinctive eyelid or why it blinks so often. One theory is that it’s a useful way to communicate with other Dippers around noisy mountain streams – perhaps a type of avian semaphore.
Hope you enjoyed reading about the American Dipper. Next week I’ll cover the Chinese Hwamei. If you missed last week’s bird, click here to read about the Spruce Grouse.