DIPPERS: Cinclidae

PHYSICAL CHARACTERISTICS

Of all Passeriformes, or perching birds, dippers are the only true aquatic songbirds. They have plump bodies with short tails, strong legs, and powerful feet. Their preen, or oil, glands are larger than those found in most perching birds and help keep their feathers waterproof. This is essential because dippers spend most of their lives in or near rivers and streams. Their eyes have nictating membranes, or inner eyelids, that allow the birds to see underwater.

Most species are uniformly gray or brown, but some species have white heads or underbellies. All dippers have white eyelids and short, hard bills.

GEOGRAPHIC RANGE

Dippers can be found in Europe, Asia, North Africa, and the western regions of North and South America. Though conditions are suitable for dippers to nest in other areas, they have not done so.

HABITAT

Dippers make their nests above shallow mountain rivers and streams, behind waterfalls, and sometimes on rocky ledges beside mountain lakes. The water must be fast moving to keep it rich in oxygen and free of sediment and pollutants. Dippers will migrate south or to lower elevations when these water sources freeze in winter. The undersides of bridges over waterways and human-made nesting boxes have also become appropriate homes for dippers.

DIET

The main source of food for dippers is insect larvae (LAR-vee), small fish such as minnows, and fish roe, or eggs.

BEHAVIOR AND REPRODUCTION

These birds are called dippers because of the way they dip or bow when they become agitated, mate, or defend territory. They also blink their eyes rapidly, displaying their white eyelids.

Dippers are unique because they spend most of their lives in water, often submerged, searching for food. Their waterproof feathers and the swimming motions of their rounded wings allow them to stay underwater. Their feet often grasp pebbles to anchor them to the river bottom. They will dive into water to escape predators.

The songs of both sexes, sharp "zit-zit" sounds, can be heard over the roar of rushing water.

Generally, dippers mate for life and either remain in a familiar nesting area or return to it yearly. Their nests are rounded with a wide entrance in the side. Both sexes build the outer nest with moss, grasses, and leaves, but the female creates the interior of softer grasses. Because the nests are build near water, the exteriors are usually moist and may stay green.

Dippers can have two broods, or groups of offspring, hatch at the same time each year. They usually lay two white eggs in the tropics and as many as seven in other climates. Females incubate their eggs, keep them warm for hatching, for sixteen days. They are then fed by both parents for up to twenty-two days.

DIPPERS AND PEOPLE

Dippers serve as an indicator species, a bird or animal whose presence reveals a specific characteristic, for good water quality.

ANTING BEHAVIOR

Though other birds interact with ants, American dippers participate in active anting, or placing ants, one at a time, into their feathers. Scientists think that ants help control parasites such as mites by spraying formic acid into the bird's feathers.

CONSERVATION STATUS

Mining, pollution, and even the presence of evergreen trees can dump chemicals, acids, and wastes into waterways that can reduce dipper food supplies and eventually decrease their populations. Currently, these birds are not threatened, though their numbers fluctuate in response to pollution. However, one subspecies of Eurasian dipper is extinct, or died out, and several other groups are Vulnerable, facing a high risk of extinction.

AMERICAN DIPPER (Cinclus mexicanus): SPECIES ACCOUNTS

Physical characteristics: The American dipper is also called the Mexican dipper, the water ouzel, and the waterthrush. It is 6 to 7 inches (15 to 17.5 centimeters) long. The male weighs 2 to 2.4 ounces (57 to 66 grams), and the female weighs 1.5 to 2.3 ounces (43 to 65 grams). Its body is slate gray with a paler throat. A flap covers their nostrils to keep water out.

Geographic range: They are found along the western coast of North America from the Arctic Circle, through Canada and into Oregon, Washington, and California, as well as in central Mexico and Central America. It is also found in Arizona, Nevada, Colorado, South Dakota, and Wyoming.

Habitat: The American dipper prefers cool climates and high altitudes, up to 11,000 feet (3,500 meters) in the United States. One group even endures the severe winters of Alaska and South Dakota, which can drop to 40° below zero F (-40°C).

Diet: American dippers walk along the bottoms of stream beds, totally submerged, hunting for insect larvae, worms, and snails. Sometimes, these birds will fly along the surface of the waterway, scooping up flies and other insects. They will also weed out sluggish insects from snowbanks and seaweed cast upon the shore.

Behavior and reproduction: This species of bird behaves like most other dippers. Its song is melodious, with a sharp "dzik-dzik" call that occurs anytime, not just to attract a mate.

Mating occurs from May to July. American dipper nests are spherical, about a foot in diameter with the usual side entrance. North American birds lay four to five white eggs, but Costa Rican birds will lay only two to four. Incubation by the female takes fourteen to seventeen days. The young fledglings are fed by both parents for twenty-four to twenty-six days.

American dippers and people: This species has been accused of causing damage to fish hatcheries, though no evidence has been found.

Conservation status: American dippers are not threatened or at risk of dying out. They are very sensitive to the water quality of the rivers and streams near their nests and will abandon them if they become polluted. Mining has contributed to water pollution in regions where American dippers nest. Bird populations are often supported and may even increase in numbers by the introduction of nest boxes placed near streams by humans and by American dippers using the undersides of bridges over waterways as nesting sites.

EURASIAN DIPPER (Cinclus cinclus): SPECIES ACCOUNTS

Physical characteristics: Eurasian dippers, also known as English dippers or white-throated dippers, are small round-bodied birds with short tails. They are only 6.7 to 7.9 inches (17 to 20 centimeters) long. Males weigh between 1.9 and 2.7 ounces (53 to 76 grams), and females weigh 1.6 to 2.5 ounces (46 to 72 grams). Most of them have dark brown feathers on their heads, backs, and bellies, with white chests and throats. Some birds have blackish feathers on their backs with chestnut brown on their undersides and only white on their breasts and chins. The black-bellied dipper has no brown on its belly, while a subspecies in Asia has a white underside.

Geographic range: Eurasian dippers can be found in Great Britain, Norway, Spain, Italy, Greece, and France, as well as western Europe, Turkey, North Africa, and Asia from the Himalayas to China. In winter, birds in Scandinavia will move south into Poland and Russia.

Habitat: Like other dippers, Eurasian dippers nest near swift-moving mountain streams. Sometimes, this species can be found near the rocky shores of lakes.

Diet: Eurasian dippers usually feed on the larvae of aquatic insects like caddis worms and beetles. They also like freshwater mollusks, water fleas, newly hatched fish, and roe.

Behavior and reproduction: Eurasian dippers behave as other dippers, and feed underwater. Both sexes sing and have a "zil-zil" call. Males change their call to "clink-clink" when they are seeking the attention of females during mating.

This species generally mates for life and will often have two or three broods. They will separate after the young are on their own and will return to their home nests in the spring.

Both sexes help build their oval nests above rushing streams or rivers, usually in rock faces or in the support pieces of bridges. One to seven white eggs are laid and incubated by the female for twelve to eighteen days. Both parents feed the young birds for twenty to twenty-four days.

Eurasian dippers and people: This species, like most dippers, has no special significance to humans.

Conservation status: Though the Eurasian dipper is not threatened, most populations have shown declines due to water pollution and increased acids caused by runoff from planting evergreen trees. If the water quality improves, the birds return to their former nesting sites. ∎

FOR MORE INFORMATION

Books:

Brewer, David, and Barry Kent Mackay. Wrens, Dippers, and Thrashers: A Guide to the Wrens, Dippers, and Thrashers of the World. New Haven, CT: Yale University Press, 2001.

Robbins, Michael. Birds (Fandex Family Field Guides). New York: Workman Publishing Company, 1998.

Tyler, Stephanie J. Dippers. San Diego, CA: Elsevier Science & Technology, 1994.

Weidensaul, Scott. Birds (National Audubon Society First Field Guides). New York: Scholastic Trade, 1998.

Periodicals:

Barber, Robert E. "Joy-bird." American Forests (Spring 1996): 34–35.

Osborn, Sophie A. H. "Anting by an American Dipper (Cinclus mexicanus)." Wilson Bulletin (September 1998): 423–425.

Turbak, Gary. "The Bird That Files Through Water: Scientists Continue to Marvel at the American Dipper. A Species Remarkably Adapted for Life Near Raging Rivers." National Wildlife (June–July 2000).