The Barn Swallow, An Ace Pilot
Zero in On Those Insects...
This bird has been more welcome than any other on farms, as it eats so many insects that destroy crops. It generally nests inside barns, outbuildings, and other buildings. It is the sole North American swallow with buff to cinnamon underparts, underwings, and a deeply forked white tail. That’s why this bird appears to look different to people all over the continent. The female is similar to the male, perhaps a little duller in coloration. The young have shorter forked tails, of course, and creamy white underparts. This swallow has been found wintering or breeding on nearly all the continents.
Although typically one tends to think of the small passerines as insectivores, many birds eat insects. Many insectivorous species turn to other diets at other times of the year, which is why they possess small, all-purpose bills. It just isn’t always possible to be a full-time insectivore in temperate areas.
Feeding and Courtship
Swifts and swallows both take very tiny prey such as aphids and young spiders that are being blown along on their gossamer threads. Insects are caught in flight, and they feed close to ground or water. When they are seen skimming water, they are picking up prey. They will follow farm machinery and lawn mowers, to feed on the stirred-up insects.
Courtship is interesting. Flights could include the pairs dropping and catching feathers in mid-air, and upon landing, they may engage in mutual preening. Each bird shows very strong site fidelity, and colonies could exist over great periods of time on the same site. Even the same individuals will build nests on the same site used the year before.
When raising young, swifts take back large boluses of insects to their nestlings. It may take hours to collect the large ball of insects, and some of the young will only be fed four or five times a day, or perhaps less, if the weather is cold and insects just are not available. All these birds that feed on aerial insects are dependent upon a good supply year round, they don’t change their diet. Almost all birds that hunt prey in the temperate zones spend the winter in more tropical climates.
The Unusual Nests
The cup-shaped nests are made of clay or mud, dried stems, grass, and straw, with a thick lining of horsehair, down, and feathers. Both sexes build the nest, which may be found in ridges of cliffs, under bridges and culverts, attached to a riverbank, inside barns or other buildings. There are usually two broods per year, unless these birds are in the northern climate zones.
Why Do Birds Build Nests Where They Do?
There are two chief ways in which birds in general seek to protect their nests. The most widely used, especially with small birds like these, is concealment. By hiding the nest in an out-of-the-way place, covering it with camouflage material, and taking care to visit it in a cautious way in order to not draw attention to it, birds hope to protect their young. The second method is to put the nest in inaccessible places, which is the case with these birds. These birds generally group together, which is another term for gregarious.
These Birds Were Made That Way!
These birds are distinctive and very cosmopolitan. Many of them are commonly known as martins, though there is no significant difference between swallows and martins. All of them have long wings and agile flight, and almost feed entirely upon the insects that they catch in the air. The neck and legs are short, and the feet are small and weak, most notably due to the fact that they are constantly in flight. The only time that they seem to cease this activity is when they are actively nesting. They are rarely found on the ground, as they are clumsy there, and know that they would be a target for prey. One of the swallow’s most outstanding feature is the short, flattened, and broad bill which can be opened in a very wide gape, which forms a very highly effective insect trap. It also acts as a trowel for scooping up mud for nest building.