Yosemite National Park, CA: Video of Shared Nest Building by Pair of American Dippers
Posted by Don Crockett on May 2, 2012
On Monday afternoon, April 16th, the day after I arrived at Yosemite National Park, I read in the description of a bird walk offered on Monday and Thursday mornings that American Dipper was one of the species that might be seen on the walk. I've always been fascinated by dippers but I didn't know much about them. I'd only previously seen them on one occasion. Later in the day, when I was standing on a bridge, I saw a chunky gray bird flying low over the water with some nesting material and thought "Dipper!" The bird flew under the bridge and didn't come out the other side. I looked under the bridge and there was a spherical nest in the process of being built. I saw 2 birds coming in every few minutes with nest material but when I set my camera up to video the nest building, the birds didn't show up for 15 minutes, so I decided to leave, afraid I might have caused the birds to abandon the nest. I came back Tuesday afternoon and both birds were coming in with nest material. I was able to video some of the nest building and other behavior that afternoon and over the next week.
The dippers were pretty oblivious to me. I could walk within 15-20 feet of them when they were gathering nest material, feeding, preening, or singing without much reaction. I did inadvertently flush them a handful of times over the course of a week when I came up on one of them too fast, not realizing how close they were. Once when I was sitting on the river bank with my camera aimed at the nest 30 feet away both birds landed nearby and started collecting nest material, coming as close as 8 feet.
I was curious about how much the male was helping with the nest building. I had read several different species accounts on dipper nest building behavior:
- "Sibley Guide to Bird Life and Behavior"
- Female, often with male's help, builds a spherical, covered nest...
- Kaufman's "Lives of North American Birds"
- Nest (probably built by female) is a domed structure about a foot in diameter...
- Cornell's "All About Birds"
- The female builds the dipper's domed, ball-like nests...
- Cornell and AOU's "The Birds of North America"
- Both sexes may help build nest (Bakus 1959a, Sullivan 1973), but in some pairs male does not help (Whitney and Whitney 1972). Male may gather nest material and bring that to female at nest (HEK).
From causal observations I could not tell a difference in the behavior between the 2 birds. Both birds were coming in regularly with nest material. If a bird was already at the nest when a 2nd bird would fly up, a bird would fly out almost immediately. Based on the above species accounts I wasn't sure whether the male was actually helping with the nest construction or just bringing in material that the female then incorporated into the nest. Reviewing the video I shot on Wednesday though it was obvious that not only were both birds bringing in nest material, both birds were also actively constructing the nest. If you watch the video below you will see 3 different nest exchanges. In each, a dipper is working on the nest when a 2nd dipper flies in and stands at the entrance until the 1st dipper quickly departs. The 2nd dipper then starts working on the nest. With a quick review of these 3 clips and others I shot I have not seen a difference in the nest building behavior of these 2 individual birds.
Feel free to comment below on the video or experience you have with American Dipper nest building behavior.
Shared Nest Building by Pair of American Dippers at Yosemite National Park
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