Tree Swallows (Tachycineta bicolor) are charming little birds that are found over most of North America and Canada. They do not inhabit the Southeastern United States, which is certainly a prime mosquito infested area. For those of you who live in their native zones, they can be voracious mosquito eaters.
A distinctive blue or green back with a white underbelly characterizes their appearance. Only 5 inches long, they are famous for their aerial acrobatic antics. This little songbird is a heavy mosquito feeder. They are known for a hunting style known as “hawking”, in which they will suddenly dart upward to snare a flying insect.
Like purple martins, they will quickly inhabit nesting boxes set out for them, and you can put out several boxes in your yard. Be sure it is at least five feet above ground and out of direct sun.
Some of them will mate and pair for several years in a row. Others find new mates each year. They have a strong preference for mating near water such as lakes, marshes, or wet meadows. All of these places are also great places for mosquito breeding. They also feed on midges, gnats, horseflies, moths, grasshoppers, dragonflies, and mayflies.
Tree swallows, while only aggressive to insects, are plagued by harassment from house sparrows and starlings. Both of these birds will sometimes raid the swallow’s nest and kill the young along with the adult guarding them.
They have viscid saliva that acts like a piece of sticky flypaper, which is very effective in catching flying insects.
If you decide to install houses for them, consider planting some bayberry nearby. They feed on the berries in cold weather, when insects are not as prevalent. Tree swallows over winter in Mexico, Central America and Florida.