Peregrine falcons have been recorded diving at speeds of 200 miles per hour (320 km/h), making them the fastest-moving creatures on Earth. Though owls are typically solitary, the literary collective noun for a group of owls is a parliament. The family scientific name for swifts (Apodidae) means 'without feet', since they have very short legs and never settle voluntarily on the ground, perching instead on vertical surfaces.