The barn swallows (Hirundo rustica) are back for another breeding season. Each year barn swallows build their nests and raise their broods using a flat ledge under the eaves on our back porch and against the wall under the eaves on the south side of our house (near Lookout CA/Modoc County). I can again sit at my desk or stand at the kitchen sink and enjoy a front-row view of this yearly cycle.
Barn swallows originally built their nests in sheltered crevices in cliffs or shallow caves. Now they choose sites in open buildings (barns, sheds, stables) or under bridges, docks, wharves or culverts. It is rare to currently find a barn swallow nest in a place that is not man-made.
Barn swallow nests are full (on flat surfaces) or half (against a wall or vertical surface) cups built of mud and lined with feathers. With their bills, both members of the pair make pellets of mud or mud mixed with grass stems. Using the pellets the nest is formed by first constructing a shelf or platform to stand on then building up the sides.
Four or five white eggs (sometimes 6, rarely 7) spotted with brown are incubated by both parents for 13 to 17 days before hatching. The chicks are fed and tended by both parents until fledging 18 to 23 days after hatching. Occasionally offspring from previous broods help feed and tend the young.
Barn swallows have one or two broods per year. Over the years I noticed that “our” barn swallows usually fledge five youngsters in the first brood. The second brood of the year is less vigorous and only 3 or 4 eggs hatch and develop to maturity. Often the pair will attempt a third brood. However, by late summer daytime temperatures under the eaves are so high that the eggs never hatch or the young die from the heat. It is always sad to watch the parents struggle with this third attempt.
Mud, feathers and fecal material make a mess on the porch, windows and side of the house. I am not certain how many mosquitoes the barn swallows actually eat (they do eat flying insects). But I convince myself each year that they eat great quantities of mosquitoes. Added to the fact that I love watching the barn swallows build their nests and raise their families, I figure putting up with a little inconvenience and grime is a small price to pay. I am delighted the barn swallows have returned.