For the Birds Radio Program: Adobe Birds
(Recording of a Cliff Swallow)
Adobe Birds are back in town–those little birds that build mud igloos under the soffit on houses, on the brick facade of the Environmental Research Laboratory on London Road, and on the dredge at Barker’s Island. You can see the little white triangular mark on their foreheads as they peek out through the round entrance hole in their nests. When they fly, their rusty rump is also noticeable, as well as their squared tail. I’m talking about Cliff Swallows.
Cliff Swallows are the famed Swallows of San Juan Capistrano, which supposedly return to the California mission on March 19 every year. Their return to Duluth every spring is not quite so regular–they come in anytime from mid-April through early May. They’re nicknamed eave swallows, jug swallows, and mud swallows for their nesting habits–some books also refer to them as Republican swallows, although a recent informal poll indicated that in fact they have no strong political affiliations, and that few, if any, of them are registered to vote.
Cliff Swallows are unique for having probably the longest migration distance of any land bird. They winter in South America from Southern Brazil all the way down to Argentina. When they return in spring, some go as far north as Nova Scotia, northern Ontario, and northern Alaska.
Cliff Swallows eat an abundance of flying insects–not only such crop destroyers as weevils and adult corn rootworms, but also plenty of mosquitoes. I suppose that means they are at least indirectly subsisting on human blood.
Cliff Swallows collect mud in their mouths and mix it with a generous helping of saliva to build their nests. Construction work tends to arouse them–you can often watch them mating in the mud during their coffee breaks. They lay four or five eggs during the two nestings each summer. Many of the babies starve during cold, rainy periods when mosquitoes and other flying insects are hard to find. Many more are killed when fastidious humans dislodge the mud nests from their homes. And many are killed in accidents or eaten by Sharp-shinned Hawks during the long migration flight. So even though each pair produces about ten young every year, the population of Cliff Swallows remains pretty much the same in the long run. As long as there is mud in Duluth, our adobe birds are here to stay.
(Recording of Cliff Swallows)
This is Laura Erickson, and this program has been “For the Birds.”