The Tree Swallow is a member of the family Hirundinidae, within the Order Passeriformes with a breeding range over much of the US and Canada. Males are iridescent blue on the back, while females are brown.  It likes open or wooded areas near water and nests in natural or artificial cavities.  Nest boxes have allowed it to extend its habitats from woods to open areas.   It migrates south in winter to southern states or down to Panama.