Although all swallows are socially monogamous, barn swallows differ in the sharing of parental care, raising 2 broods a summer of 2-7 eggs each.
Although all swallows are socially monogamous, barn swallows differ from most swallow species in the sharing of parental care. In North America, both parents incubate the eggs, which hatch in 13 to 15 days. However, females provide more parental care than do males.
Barn swallows usually raise two broods of chicks each summer. The female lays a clutch of two to seven eggs, with an average of five.
The chicks are naked and helpless when they hatch. Both parents feed and protect the chicks, as well as remove fecal sacs from the nest. During the nestling period, barn swallow parents may feed their nestlings up to 400 times per day. Barn swallows feed their chicks insects compressed into a pellet, which is transported to the nest in the parent’s throat. Juveniles from the first brood of the season have even been observed assisting their parents in feeding a second brood.
The nestlings remain in the nest for about 20 days before fledging. When barn swallows are handled by humans they tend to attempt to fledge at least a day too early. The parents continue to care for the chicks for up to a week after fledging, feeding them and leading them back to the nest to sleep. By two weeks after fledging, the barn swallow chicks have dispersed and often travel widely to other barn swallow colonies.
Young barn swallows are able to breed in the first breeding season after they have hatched. Generally, young barn swallows do not produce as many eggs as do older birds.