A male tree swallow (Tachycineta bicolor) defends his nestbox and nestlings from a takeover from another tree swallow. Beaumont, Alberta, Canada.

- Image ID: RPTMT9

A male tree swallow (Tachycineta bicolor) defends his nestbox and nestlings from a takeover from another tree swallow. Beaumont, Alberta, Canada.

Felix Choo / Alamy Stock Photo

Image ID: RPTMT9

Location: Beaumont, Alberta, Canada