-Alouette field Naturalist Notes
April is the month of the Swallow's return. Although some, like the Tree Swallow and the Violet-green, may arrive in the middle of March, large concentrations of them are not usually found until April is well on its way.
Most of us welcome their return, not only because they represent the coming of spring and we missed their cheerful twittering during the long winter months, but their presence around our yards means we have our own mosquito control ready to go into action. One swallow can consume over 2,000 mosquitoes a day. Since swallows, unlike most birds, have no crop in which to store large quantities of food for later digestion, they must feed continuously in order to survive. For this reason, they are Specially equipped with long triangular wings for swift, maneuverable flight. Like other birds which must catch insects on the wing, they have particularly long bristles around their bills. These bristles have Sensory nerve cells at their base and act as organs of touch. Their eyes, also are specially adapted, by being capable of instantaneous shifts of focus from far to near. This is vital in all birds which must pursue their prey at great speeds. Since all their feeding is done in the air, swallows have no need for strong legs and feet so, as a result, their feet are small and weak and their legs are scarcely noticeable as they perch on the telephone wires. In our area we have five different species of swallows. The Tree swallow and the Violet-green have already been mentioned, and these are the only ones which will nest in nesting boxes. The Barn Swallow and the Cliff Swallow readily nest under the eaves of barns or other buildings, using small balls of mud to build their nests. The Rough winged Swallow nests in burrows in narks of sand or clay, usually in the vicinity of water. Plans for nesting boxes for Tree Swallows may be obtained through the Alouette Field Naturalists, who put up some 70 boxes last year.
There seems to be no real preference about which direction the box should face as we have had them facing in every direction with equal success. Height also can be variable, with some of our boxes at eye level and others 20 feet up in the tree. The boxes can be made so that they may be cleaned out each year but this is not essential. No roost is necessary below the entrance hole, as swallows land right on the edge of the hole itself. Sometimes the birds spend weeks quarreling over nesting boxes before they actually begin to build in them. When they show an interest in nest-building, one can scatter a few feathers around the yard, this stimulates their nesting activities and it can be quite amusing to watch them vieing over the falling feathers. They appear to prefer fairly stiff feathers about 3 or 4 inches long, as opposed to down, although they will accept down if there is nothing else. Barn Swallows and Cliff Swallows can be encouraged to build on the sides of outbuildings if some sort of ledge is placed up near the eaves. If the weather is dry, they have a hard time finding mud for nests, a puddle of water left lying of clay soil can be a source of material for them.
It is fascinating to watch the Cliff Swallows as they build their gourd-shaped nests with hundreds of clay pellets. Not until they are completely satisfied with the architecture of their clay home will they begin to feather the inside. If you erected swallow boxes last year and had no luck in attracting a family of swallows, don't despair – it may take them a while to get used to the idea of nesting in that particular area. Once they have raised a family in one of your boxes, you should have no trouble the next year in acquiring tenants for as many boxes as you may care to provide.
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