Un-mated male barn swallows often associate with a breeding pair for an entire season, helping with nest defense, nest building, incubation, and brooding, and may succeed in mating with the resident female.

Un-mated adults often associate with a breeding pair for up to an entire season. Though these helpers do not usually feed the young, they may help with nest defense, nest building, incubation, and brooding.

Helpers are predominantly male, and may succeed in mating with the resident female, leading to polygyny.

^{• Image | © Michael Levine-Clark, Some Rights Reserved, (CC BY-NC-ND 2.0)
• Sources | (Bolzern, Moller, & Saino, 1997; Brown & Brown, 1999; De Lope & Moller, 1993; Moller, June 1994, July 1994, 1995; Roth, 2002)}

Learn More About the Barn Swallow