Since the Pleistocene, at least, Vaux’s swifts have utilized the over-night shelter of massive standing dead trees or hollowed out living trees to gather in communal roosting sites before embarking on their fall migration to Central American over-wintering grounds. Now, since most of those ancient trees are no longer, swifts have adapted to also seek shelter in large chimneys like this one at the Rio Lindo Academy in Healdsburg.
