by Jeannie Marcure
One of my favorite things about bird watching is that it can be done almost anywhere and can easily be combined with other pastimes. If you’re quietly aware of the natural world around you, great birding moments often happen when you least expect them. One such serendipitous moment occurred for me last summer as my husband and I took our annual hike to Virginia Falls in Glacier Park on July 8, a good 2-3 weeks later than usual due to the late opening of Logan Pass. Near the bridge below Virginia Falls, a small dark bird flew in and landed on a rock across the stream. After a quick check with the binoculars and because of the bobbing motion as it perched there, I recognized this bird as an American Dipper. Further inspection told me that this was not an adult but rather a newly fledged juvenile. Shortly after its somewhat uncertain landing, the small bird began to call loudly, and almost immediately an adult Dipper appeared with a morsel which she promptly offered to the juvenile. This continued for 20 to 30 minutes with the juvenile never entering the water and the adult returning with food every few minutes. Although I’ve often seen Dippers in this area, this was my first chance to observe a juvenile and its interaction with its parents, so I was motivated to learn more about these unusual little birds.
With a uniformly slate-gray color, long legs, a somewhat stocky body and short tail, the Dipper (sometimes called the Water Ouzel) is 7- 8 inches long and weighs just 1.5 to 2.5 ounces. The sexes are similar but the male is larger. Its most identifiable feature is its constant bobbing as it perches on streamside rocks.
Inquiry at www.scienceperspectives.com told me that although Dippers are aquatic birds, they are not waterfowl but rather songbirds, and their closest relatives include chickadees, robins and wrens. Despite this close relationship with songbirds, Dippers spend their entire lives in or near the water of clear mountain streams and feed entirely on aquatic life, with their favorite foods including mosquito larvae, caddis fly larvae and small fish. They are often seen walking along the bottoms of fast moving streams probing for food. They can also “fly” underwater, moving upstream in the rapid water by using their wings for propulsion. Interestingly, they can also fly straight into the air from underwater. When moving to a new location, Dippers fly just above the water, even when the watercourse curves and a land route would be shorter. Because their globe-shaped nests are made of moss and mud and placed streamside or perhaps even behind a waterfall, they are hard to spot unless you’re lucky enough to see the bird entering or leaving. Both sexes sing and defend a linear mile of streamside territory. Unlike most songbirds, Dippers do not migrate to warmer climates in the winter but rather stay in the breeding territory as long as there is running water. If the stream does freeze, they move downstream just far enough to find running water again. Dippers are regularly found on the Kalispell and Bigfork Christmas Bird Counts.
Dippers possess several unique adaptations that allow them to live in the sometimes harsh environment of mountain streams. Imagine spending most of your life with your feet in that cold water! Dippers have a thick undercoat of down that protects them from the chilling temperatures of the mountain streams that they call home. They also use a preen gland which secretes oil that is used to waterproof their feathers. This gland on the Dipper is ten times larger that of any other songbird. David Attenborough, in his video series The Life of Birds, says that Dippers are so well-oiled that the resulting buoyancy causes them to have trouble staying submerged and they can only manage 15 seconds or so at a time. A low metabolic rate and extra oxygen-carrying capacity in its blood also help the Dipper. A flap that closes over the nostrils under water works much like nose plugs used by human swimmers. In addition, a highly developed third eyelid acts like a windshield wiper to help clear the eyes after diving. You can observe this eyelid as the white flash that you see every time a Dipper blinks.
Unlike most other songbirds, but similar to ducks, the American Dipper molts its wing and tail feathers all at once in late summer. It is flightless during this time.
Next time you hike or fish along one of our beautiful mountain streams, watch closely for a small dark bird flying low over the water. Listen for the buzzing trill and perhaps you too will be lucky enough to watch an American Dipper as it walks under the water searching for a meal.