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A Means To Migrate

The Aquatic Birds of Idaho

Thomas Mangelson

For animal life within the state, this scarcity makes any available water all the more important for survival. Steep mountain ranges hide portions of it in high alpine lakes and streams. Long distances of dry desert can be too vast for many animals to travel. Birds, however, possess the unique ability to fly, allowing them to access even the most remote bodies of water and making it possible for them to travel great distances to lakes and rivers during their seasonal migrations.

There are typically 100 adult Trumpeter Swans in southeast and
southcentral Idaho during breeding season, but the
population swells to 3,000 during the winter months
after birds from Canada arrive.

AQUATIC BIRD MIGRATION:

LAKES AND RIVERS

Aquatic birds include both waterfowl (like geese, ducks and swans) and waterbirds (the catch-all for water-based birds that are neither waterfowl nor shorebirds) and almost all make some kind of migration. Whether their annual migrations are a relatively small shift from areas in northern Idaho to southern Idaho and back, like that of Canada geese (Branta canadensis), or if Idaho is only one of many rest stops during a much longer journey, the state’s water provides them with a means to migrate.

“If you look at southern Idaho in general,  you’re looking at a pretty arid landscape, so the bodies of water are unique in that they’re available. They’re providing an oasis in the desert if you will,” said Jeff Knetter, Idaho Fish and Game’s upland game and waterfowl staff biologist.

One of the reasons water is so essential to their migrations is that aquatic birds often roost on the surfaces of lakes or ponds overnight. Colleen Moulton, Idaho Fish and Game’s avian science program leader, said there are even some birds, like Grebes (Podicipediformes), that cannot walk on land at all, making access to water a daily requirement.

Most aquatic birds also feed on fish, insects and plants that can only be found either in or surrounding lakes and rivers. Waterbirds such as the Great Blue Heron (Ardea herodias), which can be seen primarily in the summer, and the American White Pelican (Pelecanus erythrorhynchos), which have two breeding colonies in Idaho, one located at Lake Walcott and the other at Blackfoot Reservoir, feed primarily on fish during their time in the Gem State.

Waterfowl such as the Common Goldeneye (Bucephala clangula), which winter in Idaho, and Barrow’s Goldeneye (Bucephala islandica), which can be seen at the top of the panhandle in the summer and in southcentral Idaho in the winter, are diving ducks that eat submerged plants and small aquatic animals. Trumpeter Swans (Cygnus buccinator), which winter in southcentral Idaho and summer on the far southeastern side of the state, do not dive for submerged plants but instead plunge their long necks into the water to find food.

Without Idaho’s bodies of water to sleep on and provide food to keep them strong, many birds would not physically be able to travel the long distances needed for migration, Knetter said.

Gregory Johnston

Bob Steele

Bob Steele
 

Many birds follow what are called “flyways” to their destinations. Flyways generally run along major rivers on a north-to-south route.
Brian Sturges, who has headed the National Audubon Society Christmas bird count in Hagerman since 1974, said that although Idaho does not contain any major flyways, many birds follow the Snake, Salmon and Columbia River drainages through the state.

Sturges said birds following the Columbia River occasionally take a wrong turn at the mouth of the river and end up in Hagerman or American Falls instead of Mexico.

“There’s some food there so they sometimes stay over the winter,” Sturges said. “We’ve had ocean-going birds, birds from Alaska and birds from Asia down there, so Hagerman is a really fun place because you never quite know what might pop up there.”

And although the rivers in Idaho do not see as many migratory birds as flyways like the Mississippi, Moulton said the Gem State is unique because so many birds can be seen in any single wetland area.

“I think the thing that stands out the most (about waterways in Idaho) is that we have so little water compared to the eastern part of the country. This makes the water we do have really important because birds have to go many miles before they find water, and so waterbirds tend to gather in greater abundance here in Idaho because they have fewer places to choose from,” Moulton said.

Canada Geese: Marty Ellis / Common Goldeneye and American White Pelican: Bob Steele

BIRD WATCHING:

WHERE TO SEE AQUATIC BIRDS

Generally speaking, most waterfowl spend the winter in Idaho, whereas waterbirds tend to pass through the state in the fall and spring or stay through the summer. This makes aquatic birdwatching possible at almost any point of the year. Fall and spring, however, see the most diversity because of the mass movements through the state.

Waterbirds tend to gather in greater abundance here in Idaho because they have fewer places to choose from.

To see aquatic birds, Knetter and Moulton recommend visiting either Market Lake (off Interstate 15 in eastern Idaho) or Mud Lake (just outside Idaho Falls on Highway 33). The lakes have a high diversity of species that stop through, Knetter explained.

In the springtime, Northern Pintails (Anas acuta), a type of dabbling duck, are common. In the summer, many Grebes nest around the lakes, and in the fall it is estimated that 50 American White Pelicans stop at the shores of Market Lake.

Moulton suggested visiting Gray’s Lake (in southeast Idaho, off Highway 34) in April or May for those interested in seeing Sandhill cranes (Grus canadensis). The slender birds can have wingspans upward of six feet and travel in large flocks. Gray’s Lake has some of the highest numbers of nesting cranes in the world.

As a general rule of thumb for birdwatching, Wood River High School biology teacher Larry Barnes suggested looking where there’s water. “Diversity increases where there’s water,” Barnes says. “In Hailey, the best is the confluence of the Big Wood River and Croy Creek. That wetland is kind of a Silver Creek north because it’s really quite diverse.”

Barnes also recommended spending a day at the Silver Creek Preserve, where 150 different bird species have been reported. Knetter also recommends the Camas Prairie Centennial Marsh Wildlife Management Area near Fairfield.

And even in the late summer and into the fall, once much of the water in Idaho has begun to dry up, Moulton said mudflats are a good place to find birds. The absence of water exposes insects and plants that only diving birds could access before, which turns mudflats into massive feeding grounds for migratory birds.

Whether it’s the soft and nutrient-rich soil that remains where water once was or the plentiful feeding environment and shelter that lakes can provide, the small pockets of water throughout the state make it possible for aquatic birds to exist in the high desert climate of Idaho.


 


 

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