Bushtits nest building together

Very close to a photo blind at the William L. Finley National Wildlife Refuge just south of Corvallis, Oregon, we witnessed a pair of Bushtits building their ‘sock-like’ nest. We observed it over a period of six weeks or so, from near the beginning of building it until the young were being feed, apparently, as you can’t see inside but the adult activity would indicate that’s what was going on. Their movement in the ‘sock’ was comical to watch as a bulge would form as they entered, slide down and around inside.