While birding in Mccall, Idaho this week, Alex and I took a drive up Lick Creek Road. Most of the open water was still frozen and snow was still packed in the forest, but this fast running stream provided perfect habitat for a pair of American Dippers. American Dippers (Cinclus mexicanus) can be found in clear mountain streams, where they dive under the water to feed mostly on larvae, insects, worms, and fish. Mostly, they dip their heads below the water, grabbing for food under rocks, but they often completely submerge themselves for 5-10 seconds at a time. Dippers can be hard to spot with their dusky gray color against similar color rocks, but once you find them, their unusal behavior is unmistakable as they constantly “bob” down the edges of streams looking for goodies.
Once again, I was amazed at the ability of an extremely small bird to stay warm in freezing conditions. Unlike the locals who were out in T-shirts and shorts (seriously), I was layered up with thermals, a wool sweater, and a down coat. This river contained freezing cold water from snow melt, and the temperature outside was only in the 30’s. This bird suffers through far worse, and has to move into lower elevations as its streams freeze over in the winter. Apparently, dippers have a larger preening gland than most birds, which provides them with extra oil to coat their feathers with to keep warm in icy mountain streams. Water rolls right off them like a duck. Dippers also have a higher level of hemoglobin in their blood which helps them store more oxygen while they are submerged under water, and they also have a very low metabolic rate. If you look closely, you can see the nictating membrane opening under its white eyelid as the bird resurfaces, which helps it see under water. Basically this bird has adapted its physiology to thrive in an open niche where it competes with trout rather than other birds species.
I was able to take a video that not only captures my inability to take videos, but typical behavior of American Dippers. Other videos on youtube aren’t much better, so I’ll make it a point to take a better video next time I find these guys. Note how the birds constantly bob along, and sometimes completely submerge themselves, where they cling to rocks under water and use their wings to shoot through the water. The bird on the right catches a long insect larvae, attempts to kill it, but then drops it and dives back in for it. I can’t get the video to upload here…but you can check it out on my blog.