Polygamy Among Birds.—As with mankind, some races have well-developed tendencies toward polygamy. In the warmer regions of the United States there dwells a great, splendid, glossy Blackbird, the Boat-tailed Crackle. The nest of this bird is a wonderfully woven structure of water plants and grasses and is usually built in a bush growing in the water. When you find one nest of the Crackle you are pretty certain to find several other occupied nests in the immediate vicinity. From three to six of these marvellous cradles, with their quiet brown female owners, often appear to be watched over by one shining, iridescent lord Crackle, who may be husband to them all. He guards his own with jealous care. Evidently, too, he desires the whole country to know that he is the most handsome, ferocious bird on the earth; for all day long his hoarse shoutings may be heard, and when he launches into the air, the sound of the ponderous beating of his wings can, on a still day, be heard half a mile away, across the lake.
One of the best-known polygamous birds of North America is the Wild Turkey. Go into any part of the country where this fast-disappearing game bird still survives, and the experienced local gunners will tell you that in the mating season you will usually find a gobbler accompanied by two or more Turkey hens. When a female gets ready to make her nest she slips away from her sultan and the other members of the seraglio and, going to some broom-sedge field or open place in the woods, constructs her nest on the ground beneath some slight, convenient shelter. Day after day she absents herself for a short time, and the speckled treasures grow in number until from twelve to fifteen have been deposited. All this time her movements are characterized by absolute secrecy, for if the gobbler by any chance comes upon the nest he immediately breaks every egg. He is perhaps wise enough to know that when his hens begin to set lonely times are in store for him.
The Outcast.—One of our wild birds whose domestic relations are not fully understood is strongly suspected of being promiscuously polygamous. Suspicion on this point is heightened by the fact that it never has a nest even of the most humble character, and shuns absolutely all the ordinary dangers and responsibilities of parentage. We call this seemingly unnatural creature the Cowbird, probably because it is often seen feeding in pastures among cattle, where it captures many insects disturbed into activity by the movements of the browsing animals.
The Cowbird lays its eggs in the nests of various other birds, distributing them about the neighbourhood. Here they are left to be hatched and the young to be reared by the foster parents. Cowbird's eggs have been found in the nests of nearly one hundred species of birds, and nearly always the nest of some smaller bird is chosen. Despite this fact the Cowbird's eggs are often first to hatch. The young grow rapidly and, being strong and aggressive, not only secure the lion's share of the food, but frequently crowd the young of the rightful owner out of the nest to perish on the ground beneath.
As soon as the young leave the nest the greedy Cowbird follows the little mother about the thickets, shouting loudly for food. Its fierce clamour drowns the weaker cries of the legitimate young, which I have reason to believe even then often die for lack of nourishment. So insistent is the young Cowbird and so persistently does it pursue the foster parent that it is well cared for and invariably thrives. It is no uncommon sight, during the days of June and July, to see a worn, bedraggled Song Sparrow working desperately in a frantic effort to feed one or more great hulking Cowbirds twice its size. It is little wonder that discerning people are not fond of the Cowbird. Even the birds seem to regard it as an outcast from avian society, and rarely associate with it on friendly terms. This is the only species of North American birds that exhibits such depravity.
The Greedy Young Cowbird
All other birds display great willingness to attend to their home duties, and often give evidence of keen delight while so engaged. One of the most exquisite and dainty forms of bird life found in the United States is the little Blue-gray Gnatcatcher. When occupied in building the nest, which is usually saddled on the limb of some forest tree, the birds call to each other constantly; and even after the eggs are laid there is no attempt to restrain their expressions of happiness. Unlike the Crow and Jay, that sometimes appropriate the nests of other birds, these little creatures have no sins to answer for to their neighbours. One of the most pleasing sights I have witnessed was a male Gnatcatcher that had relieved his mate at the nest. He was sitting on the eggs and, with head thrown back, sang with all his might, apparently unconscious of the evil which such gaiety might bring upon his household.