Upside down is easy for this avian acrobat. Bushtits are diminutive, agile and nimble; they scramble, dangle and wrangle in search of food and nesting material.
They often travel in packs and are sometimes so consumed with their gleaning activities that they are indifferent or oblivious to nearby humans. This male (see the yellow eye) was no more than 18 inches from me in a chest-high bush while I took many shots.
Earlier in the day, he snagged a great blue heron feather which had fallen from the nesting colony above his own nest.
This bushtit and his mate have fortuitously chosen their nest location--there will continue to be a supply of heron feathers falling from above throughout the summer.