ON THE WATERFRONT
Just about all birds can be described as birds of the air. They fly. Most of them are good at it. A few, like the recently-returned SWIFTS, SWALLOWS and SANDMARTINS are absolute masters of their crafts.
But birds can be divided into more specialised groups when they land. For example, Passerines are, by definition, perching birds. When not airborne they spend much of their time balancing and clutching…