Swallows are very popular summer visitors to Long Island. Aside from their beauty and grace they are natural weapons in the battle against the mosquito. From the family of passerine birds, swallows are distinguished by their long pointed wings. They have small legs and feet. And, they have round heads with short bills with wide mouths, well designed for feeding on flying insects. They are almost totally insectivorous, eating flies, mosquitoes and gnats.
Swallows are swift and graceful fliers, eating and drinking on the fly. It has been estimated that a swallow may cover 600 miles per day gathering food for its nestlings. All swallows migrate only by day and they feed on insects as they travel, thereby enabling them to make great distances each day. They are social birds, traveling in flocks and in, some cases, nesting in colonies. They gather in huge flocks, which can include more that one variety of swallow, in late summer and by the end of September they vacate their northern breeding area.
There are three varieties of swallows common in our area: the barn swallow, the tree swallow and the purple martin.
The barn swallow is the most common swallow, world wide. It is a long-distance migrant that breeds in the northern hemisphere and winters in the southern hemisphere, sometimes as far south as Argentina. Most barn swallows nest in man-made structures, where they construct a mud and grass cup, reinforced with feathers and soft material, supported by a sheltered ledge or rafter. They average around 6 inches long and have deeply forked tails. Barn swallows are blue-black above with creamy underparts and chestnut throats and foreheads. Female barn swallows are duller in color and their tails are shorter that males.
Tree Swallows are about the same size as Barn swallows but their notched tails lack the deep forked profile. They have metallic steely blue-green upperparts and white underparts. Tree swallows lay 4 to 6 white eggs in a feather lined cup of grasses installed in a tree or a nest box. They don’t migrate as far south as barn swallows and can feed on berries in the winter if they find insects scarce.
Purple martins are our largest swallow, averaging over 7 inches. The adult male is a dark steel blue all over while the female and young have gray underparts and foreheads. They lay their 4 or 5 white eggs in a clump of plant material stuffed in a natural cavity or in an apartment-style martin house. They prefer to nest in colonies rather than singly and a martin house is a special structure designed with this in mind. The practice of erecting a group house to attract these insect eliminators was used by early new world settlers and their native American predecessors who hung clusters of hollow gourds near their precious crops.