This video from the USA says about itself:
Violet-green Swallows Gather California Condor Feathers, May 3, 2016
A pair of Violet-green Swallows visit the condor nest to gather feathers for their nest site. Watch the cam live here.
The condor cam is a collaboration between the Santa Barbara Zoo, the US Fish and Wildlife Service, and the Cornell Lab of Ornithology.
The Cornell Lab of Ornithology writes about this:
Last week, a couple of these birds visited our Bird Cams California Condor nest to gather some feathers as the condor chick looked on—how neat to think that critically endangered condor feathers are doing double duty as nest lining.
Pingback: Birds nesting in California, new research | Dear Kitty. Some blog
Pingback: California Condor Chick Plays With Sticks | Dear Kitty. Some blog
Pingback: California condor chick growing up | Dear Kitty. Some blog