Nature up close: The American dipper

By "Sunday Morning" contributing videographer Judy Lehmberg.

A woman visitor came running up to a park ranger and excitedly said, "Ranger, ranger, you have to do something! There is a little gray bird trying to commit suicide!" The ranger remained calm and asked the woman why she would think that. She said, "It must be trying to kill it self. It just jumped right into the creek." The ranger then explained the bird she was watching was actually trying to find something to eat and had no intention of killing itself.

I've been hearing that story for years, ever since I became aware of dippers. They are a unique bird, a bird I never tire of watching and whose habits are pretty amazing. There are several species of dippers worldwide, all living near cold, highly-oxygenated streams and feeding on aquatic insects. The old name for dippers is water ouzel, because they resemble the Eurasian blackbird. They are more correctly known as dippers because they constantly bob up and down while standing and walking.

The only North American dipper lives in the West, including near streams in Kings Canyon National Park.

Kings Canyon National Park, in California's Sierra Nevada Mountains, is adjacent to Sequoia National Park. The two parks make up the UNESCO Sequoia-Kings Canyon Biosphere Reserve protecting the largest stand of giant sequoias in the world. The park was originally suggested by John Muir in the early 1870s, but it wasn't until Ansel Adams began photographing it that it was actually set aside as a National Park in 1940.

Kings Canyon in the high Sierras is a stellar example of a pristine watershed. The higher you go in the mountains, the purer the water. It doesn't take complex instruments to determine its high water quality. The lack of pollutants and high dissolved oxygen can be assessed by looking at the aquatic insects and their predators. Mayflies, caddisflies, and especially stoneflies require cold water and high dissolved oxygen. Stoneflies in particular are used as an indicator of high dissolved oxygen. Additionally the American dipper that feeds on these stoneflies is an indicator species; it would not be there unless coldwater-loving insects were abundant.

This medium-sized, dull, gray, drab bird is nothing special to look at, but its feeding habits are truly unique.  The dipper is the only aquatic America songbird that obtains its insect prey by diving underwater, walking on the stream bottom, and grabbing aquatic insect nymphs clinging to the rocks. As they hunt they often make short flights from one promising spot to another, sticking only their head underwater. When they spot their prey they totally submerge themselves. If they catch something big, like a large stonefly, they normally hop on a rock and beat the poor insect to death. Very rarely they catch a small fish and beat it into submission as well.

Dippers usually build their nests either above flowing streams on rocks or under bridges, but occasionally they nest behind waterfalls. Their nest is a rounded dome shape made of moss with a side entrance. Once the eggs hatch, both parents spend their day collecting insects for their chicks. After the nestlings fledge they sit on stream rocks noisily begging as their parents gather food from the stream bottom.

Dippers spend the spring and summer along the stream where they nest. In the late fall they become altitudinal migrants, traveling relatively short distances to lower elevations, as winter progresses and streams ice over.

If you find yourself hiking in the mountains don't forget to keep an eye, and an ear, out for these drab, but unique songbirds. They aren't always easy to spot, but they are easy to hear, as their call is loud, high-pitched, and always above the frequency of the nearby rushing water.

And remember: if you are lucky enough to see one dip under the water it isn't a death wish; it is just their unique way of finding lunch.

Judy Lehmberg is a former college biology teacher who now shoots nature videos.

       
For more info:

• Judy Lehmberg (Official site)
• Judy Lehmberg's YouTube Channel

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