| Natural Notes |
National Park Service U.S. Department of the Interior 2002-2003 North Cascades National Park Service Complex |
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Harlequin ducks Harlequin ducks migrate annually to North Cascades National Park in April from Puget Sound and the Pacific Coast to breed. These ducks have very specific nesting and rearing habitat requirements. They seek clean, cold, swift water and plenty of aquatic insects to eat, making them a prime indicator species for the pristine river habitats they occupy during a few months each year. Twelve streams were recently identified as suitable habitat and surveyed by park biologists. Just 29 harleqins were observed using eight of the streams.
Harlequins are only brief visitors to the park. By early May they have paired up, established territories and built their nests. Soon after the eggs are laid the males return to the coast. Females remain in the park to incubate the eggs. Together the mothers and their newborn join the males in the salt water habitats by late August. Though the ducks' time in the North Cascades is limited, it is an important part of their lifecycle. Some concern exists that the population of harlequins may be affected by the cumulative impacts resulting from habitat loss in the upper Skagit. Management policy and resource use have potential consequences for this colorful species and great care must be taken to protect their breeding habitat. Cascades: home of the 'Not-so-common' Loon Deep in the wilderness, at a wooded mountain lake, a haunting melodious call echoes off the cliffs. This is the home of the Common Loon (Gavia immer). If you are fortunate enough to see one, with its zebra-stripe necklace, glossy green checkerboard back, and sleek graceful form, you will discover that it looks as beautiful as it sounds.
The Common Loon breeds in the northern states and most of Canada and Alaska. Dramatic reduction in breeding numbers have made the term 'common' a misnomer. Washington has only a few known nests. Although dozens of loon pairs have been seen in the park, breeding wasn't confirmed until recently. Human activities have seriously impacted loons. Many birds accidentally drown in fishing nets or are illegally shot. Habitat modification, such as filling in wetlands and dams that vary water level, are also a serious threats. Natural predation is also a threat. Adults are undoubtedly captured by the occasional mammalian predator while young loons are more vulnerable and can fall prey to predators like hawks, mink and turtles. Loons appear to have a stable breeding population and relatively secure habitat in the park. Because they are migratory, most spend part of the year in unprotected habitat. Common Loons nest on the ground along the shores of lakes, on islands, or among wet soggy aquatic vegetation. Females lay one to three eggs in spring following acrobatic courtship behavior. After hatching, the fuzzy young leave the nest in just a few days and are able to swim, dive, and walk on land with ease. Common Loons prefer to eat fish, but will settle for a frog, small reptile, insect, leech, or aquatic vegetation. North Cascades neotropical breeders Each spring, as part of an amazing phenomenon that happens across the continent, birds return from Central and South America to North Cascades National Park. The Rufous Hummingbird, a familiar sight in suburban yards as well as the park, spends its winters thousands of miles away in southern Mexico. Swainson's Thrush, a robin-like summer resident more often heard than seen in the park's lower elevations, winters in areas stretching from central Mexico to northern Argentina and Paraguay. Three-quarters of North America's more than 650 bird species are migratory. Some birds that summer at North Cascades National Park accomplish impressive feats of long-distance flight and navigation each fall. Unfortunately, as human population and development expand throughout the Americas, habitat for such ecologically important migratory bird species shrinks. Long-term studies show declines in many bird populations for which the U.S. National Park System provides critical habitat. To improve protection of these birds and their habitat, North Cascades National Park and other national parks around the U.S. and in Latin America have joined in the Park Flight Programa coordinated approach to migratory bird conservation. Funding from American Airlines, through the National Park Foundation, brought biologists from Central America to work with scientists in North Cascades National Park on refining methods for assessing the status and condition of migratory bird populations. During their visit, the Central American biologists presented a public lecture and helped the National Park Service develop exhibits about birds that breed here and winter in the tropics. We share with the citizens of Latin American nations some of the birds which most characterize the Northwest. Survival of this important aspect of the North Cascades ecosystem depends on caring people protecting the habitat birds need in each season. | |
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