Jodie Merchant, age 12, of South Sioux City, Neb., for her question:
DO THE SWALLOWS COME BACK TO CAPRISTRANO ON SCHEDULE?
Swallows are widely beloved because of their value as insect eaters and because they seem to be very friendly. They are found throughout the world except for the polar regions, New Zealand and a few oceanic islands. Swallows spend much of their time on the wing. They are exceedingly graceful and among the most accomplished fliers of all the world's birds.
There isn't a more sure sign of spring than a flock of swallows. The swallows follow the sun, and as summer ends in the Southern Hemisphere, they fly northward. Long flights require the presence of insects in the air, since the swallows must feed as they migrate. And the warm weather brings out the insects.
Swallows' northward migration is governed largely by the weather. Their arrival in their northern homes can vary as much as two weeks.
The well known legend of the swallows returning to Mission San Juan de Capistrano in California says they arrive each year on March 19, Saint Joseph's Day. The charming folk tale says the birds are infallible about arriving on the right spring day.
The cliff swallows do indeed come to Capistrano faithfully each spring to nest, but their actual arrival date can be as variable as those of swallows elsewhere. A few hardy scouts often arrive ahead of the large flock, so that the legend is kept alive even when the birds are a bit late in arriving. Most years, however, the start of warm spring weather helps the large mass of birds arrive on the "correct" date.
More common in North America than the cliff swallow found at Capistrano is the barn swallow. During our winter he goes to South America. Since the dawn of history, the swallow has chosen to nest in close association with man. The friendly birds build their mud nests on the top or sides of rafters found in barns, sheds and houses. Barn swallows are faithful to their nesting territory and return year after year to the same site and often the same nest.
Both male and female swallows gather little pellets of mud which they plaster in place and strengthen with grass and straw to build their nests. Then the female lays between four and five white eggs. Although the male seems willing to help in the incubation chores, it's strictly the female's job. She has a bare space on her belly that is amply supplied with blood vessels used to keep the eggs warm. Old dad doesn't have this brood patch, so he can't provide the necessary warmth.
After 14 to 16 days the baby birds are hatched. The fledgling period is rather long; it takes from 20 to 24 days for the young birds to gather enough strength to fly.
Barn swallows often rear a second brood each season. The young of the first brood stay in the vicinity and help the parents feed the new family. Adults not otherwise engaged or those that have lost their own broods frequently help feed the young in nearby nests.