The term barn swallow refers to six different species of small blue-backed birds that are native to nearly all regions of the world, with the exception of Antarctica and Australia. Barn swallows often build their nests in and around man-made structures, including barns and other outbuildings, which no doubt inspired their name. Barn swallows adapt easily to their environment and nest in any area that provides food and water sources and a ledge that provides shelter from the elements and protection from predators.
Males and females of the species look very similar, with metallic blue or black backs, off-white underbellies and bits of light brown on their forehead and throat. Their tail feathers are quite long and distinctively forked and their wingspan measures up to 34 centimeters. Female barn swallows may have slightly shorter tail feathers or may be less vibrantly colored than males of the species.
Mating season for the barn swallow typically runs from May to August, depending on geographic location, during which the female generally produces two broods or clutches. Males and females work together to build the nest, which is constructed out of grass, feathers and mud. After the female lays an average of five eggs, both male and female take turns incubating the eggs for up to 15 days. Once hatched, most chicks remain in the nest for around 20 days before starting the fledging process. During this time, these chicks keep their parents very busy, requiring food up to 400 times per day. Within one year of hatching, young barn swallows are able to mate and produce their own hatchlings, although they may produce smaller broods than older birds.
Although barn swallows have been known to live up to eight years of age in rare cases, the average lifespan is roughly four years. Outside of the mating season, barn swallows are migratory birds, typically traveling along waterways, mountain ridges or open expanses.
Barn swallows are generally social birds, often found nesting in colonies. They can also be seen sitting on telephone wires with large groups of other barn swallows. Like most bird species, barn swallows communicate with one another through vocalizations and body language. Different calls communicate different things, such as a courting call during mating season or a warning call when predators are near.
Besides nesting near other barn swallows, these birds may also nest close to ospreys, a larger bird species that provides protection from predators. Hawks, owls, falcons and other large birds are common predators for adult barn swallows, while mammals, snakes and even bullfrogs may prey on defenseless nestlings.
Because they tend to nest in large groups, barn swallow feces can cause health concerns for humans and livestock, including the risk of salmonella. While many people find barn swallows and their close proximity to human populations to be a nuisance, they do provide an important role in the ecosystem. Barn swallows are insectivores than consume a massive amount of insects, helping to control pest populations. Catching most of their prey during flight, barn swallows commonly eat grasshoppers, crickets, flies, moths, beetles and other flying pests. They are also an important source of food for many different predator species.
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