Anna’s hummingbird nest
While helping work on a construction project in Berkeley, this hummingbird was doing some construction of its own! I noticed on the first day I was there that a hummingbird kept landing on one particular branch. The next morning, I inspected closer and realized the foundation of a nest had been built since I left the night before.
The bird would come back with feathers and other small bits of vegetation to add to the nest, and a number of times I saw it fly to the window panes around the house to gather silk cobwebs. Amazing.