tree swallow

from The Century Dictionary.

• noun An Australian swallow of the genus Hylochclidon, called in that country martin, and laying in holes in trees.
• noun The white-bellied swallow, Tachycineta (or Iridoprocne) bicolor, which still nests in trees even in populous districts of the United States.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun of Australia and Polynesia; nests in tree cavities
• noun bluish-green-and-white North American swallow; nests in tree cavities