Critters of North Idaho: Barn Swallow

Brrr! The snow and windchill always send shivers through my limbs, as I’m sure it does many humans and animals. Some bundle up or fatten up to beat off the cold; others sleep the winter away; and still some go south for the winter. If that last option’s the one for you, then you’d probably be jealous of the barn swallow! When the weather gets cold, these little birds aren’t found anywhere in Idaho because they’ve all flown down to balmy South America for the winter. Let’s join them, shall we?

There isn’t much that’s not to love about these little birds. And when I say “little,” I mean it! An adult barn swallow (Hirundo rustica) tips the scale at 17 to 20 grams, is six inches from beak to tail (give or take), and has a wingspan of a foot or so. This makes it a pinch smaller than a bluebird. The pale to rufous coloration of their underbelly is nicely contrasted from the dark blue feathers on the top of the head, back, wings and forked tail. Despite their size, barn swallows really get around. Except for Australia and Antarctica, they are native to every continent in the world, found in North Africa, Japan, China, north central Asia, and the Middle East, among other places. Unless it’s a frigid wintertime, that is! I’ve already mentioned that barn swallows in North America fly to South America for the winter, but those in the Old World fly to South Asia, Indonesia or Micronesia instead.

The secret to their wide range is their ability to adapt. They aren’t picky about where they live and nest, happily residing in any sort of open habitat with enough living space, food, and water sources, like around ponds, meadows, marshes, rock caves and fields. That being said, they’ve especially taken to human settlements like boat docks, the eaves of old houses, slow-moving trains, and you guessed it, barns and other outbuildings. These birds roost and forage in large flocks, often intermingling with other swallow species.

When it comes time to reproduce, a mated pair of barn swallows will work together to find the perfect place. They may use an old nest so long as it’s still in recoverable condition and isn’t infested with mites or other parasites. The mother bird lays between three and seven eggs in a tiny cup-shaped nest constructed from mud, feathers and bits of vegetation, usually grass. As the female incubates, the male defends the nest site from potential threats, including other males. If the attacker is too big for one swallow to handle, perhaps a gull, hawk or even a pesky domestic cat, squirrel or raccoon, a bunch of them may mob it until it vacates the area. The birds use a combination of speed and agility to avoid becoming prey themselves. Barn swallows typically rear young between May and August, raising two broods a year.

Their most unusual defense against nest invaders comes from a very unlikely source: a bird of prey called the osprey. Ospreys are eagle-like birds of prey that primarily hunt fish. You may be surprised to learn that they and barn swallows will often nest near each other and cooperate to protect their broods of eggs. Barn swallows serve as a great alarm system whenever the osprey’s threats are in the area, and few predators are willing to approach a fearsome osprey to get at the barn swallows. This type of animal relationship is called mutualism, where two or more species benefit from each other.

The occasional dead bug on the ground or an insect that is too cold to move might catch a barn swallow’s eye, but these little darting birds get most of their food and drink on the wing. When they’re thirsty, they fly low over the water for a sip. Ninety-nine percent of their diet is caught on the wing, be it grasshoppers, flies, beetles, crickets, dragonflies or moths. They will often fly around large animals, people, or farm equipment to gobble up the insects they flush out of hiding.

Unlike many creatures, barn swallows benefit from human habitation, especially in agricultural areas. If you’d like to invite these feathered friends to your backyard come warmer weather, you may want to buy an open platform feeder and fill it with ground-up eggshells or oyster shells. While they are perfectly happy building their nests in an outbuilding (especially if you leave the door or window open so they have easy access), they also love bird nest boxes. Don’t forget to leave a suitable supply of mud for them nearby that they can use to fashion their nest with. When spring returns, so will the barn swallows. They will be on the lookout for a safe place to roost and raise their chicks.

animaladventures1314@gmail.com