Part 4

It is a mistake to tear down from the eaves of a barn the nests of a colony of cliff swallows, for so far from disfiguring a building they make a picturesque addition to it, and the presence of swallows should be encouraged by every device. It is said that cliff and barn swallows may be induced to build their nests in a particular locality, otherwise suitable, by providing a quantity of mud to be used by them as mortar. Barn swallows may also be encouraged by cutting a small hole in the gable of the barn, while martins and white-bellied swallows will be grateful for boxes like those for the bluebird, but placed in a higher situation.

TOWHEE.

The towhee, chewink, or ground robin (fig. 8), as it is variously known, inhabits nearly the whole of the United States east of the Great Plains. It breeds from the Middle States northward and winters in the southern half of the country. Naturally associated with the catbird and brown thrasher, it lives in much the same places, though it is more given to haunting hedgerows along roads and fences. After snow has disappeared in early spring an investigation of the rustling so often heard among the leaves near a fence or in a thicket will frequently disclose a towhee hard at work scratching for his dinner after the manner of a hen; and in these places and along the sunny border of woods old leaves will be found overturned where the bird has been searching for hibernating beetles and larvæ. The good which the towhee does in this way can hardly be overestimated, since the death of a single insect at this time, before it has had an opportunity to deposit its eggs, is equivalent to the destruction of a host later in the year. The towhee has also been credited with visiting potato fields and feeding upon the potato beetle. Its vegetable food consists of seeds and small wild fruits, but no complaint on this score is known to have been made. So for as observation goes, the bird never touches either cultivated fruit or grain; in fact, it is too shy and retiring even to stay about gardens for any length of time.

Pipilo erythrophthalmus.

THE SPARROWS.

The sparrows here mentioned are all native species. A full account of the English, or house, sparrow (Passer domesticus), including its introduction, habits, and depredations, was published In Bull. No. 1 of the Division of Ornithology in 1889. For information in regard to combating the English sparrow, see U. S. Department of Agriculture Leaflet 61, English Sparrow Control.

Sparrows are not obtrusive birds, either in plumage, song, or action. There are some 40 species, with nearly as many subspecies, in North America. Not more than half a dozen forms are generally known in any one locality. All the species are more or less migratory, but so widely are they distributed that there is probably no part of the country where some can not be found throughout the year.

While sparrows are noted seed eaters, they do not by any means confine themselves to a vegetable diet. During the summer, and especially in the breeding season, they eat many insects and feed their young largely upon the same food. Examination of stomachs of three species--the song sparrow (fig. 9), chipping sparrow, and field sparrow (fig. 10)--shows that about one-third of the food consists of insects, comprising many injurious beetles, as snout beetles or weevils, and leaf beetles. Many grasshoppers are eaten. In the case of the chipping sparrow these insects form one-eighth of the food. Grasshoppers would seem to be rather large morsels, but the bird probably confines itself to the smaller species; indeed, the greatest amount (over 36 per cent) is eaten in June, when the larger species are still young and the smaller most numerous. Besides the insects already mentioned, many wasps and bugs are taken. Predacious and parasitic hymenopterous insects and predacious beetles, all useful, are eaten only to a slight extent, so that as a whole the insect diet of the native sparrows may be considered beneficial. There are several records of potato-bug larvæ eaten by chipping sparrows.

Melospiza melodia.

Spizella passerina.

Spizella pusilla.

Their vegetable food is limited almost exclusively to hard seeds. This might seem to indicate that the birds feed to some extent upon grain, but the stomachs examined show only one kind, oats, and but little of that. The great bulk of the food is made up of grass and weed seeds, which form almost the entire diet during winter, and the amount consumed is immense.

In the agricultural region of the upper Mississippi Valley, by roadsides, on borders of cultivated fields, or in abandoned fields, wherever they can obtain a foothold, masses of rank weeds spring up and often form almost impenetrable thickets which afford food and shelter for immense numbers of birds and enable them to withstand great cold and the most terrible blizzards. A person visiting one of these weed patches on a sunny morning in January, when the thermometer is 20° or more below zero, will be struck with the life and animation of the busy little inhabitants. Instead of sitting forlorn and half frozen, they may be seen flitting from branch to branch, twittering and fluttering, and showing every evidence of enjoyment and perfect comfort. If one of them is captured it will be found in excellent condition; in fact, a veritable ball of fat.

The snowbird and tree sparrow are perhaps the most numerous of all the sparrows. Examination of many stomachs shows that in winter the tree sparrow feeds entirely upon seeds of weeds. Probably each bird consumes about one-fourth of an ounce a day. In an article contributed in 1881 to the New York Tribune the writer estimated the amount of weed seed annually destroyed by these birds in Iowa. On the basis of one-fourth of an ounce of seed eaten daily by each bird, and an average of 10 birds to each square mile, remaining in their winter range 200 days, there would be a total of 1,750,000 pounds, or 875 tons of weed seed consumed in a single season by this one species. Large as are these figures, they unquestionably fall far short of the reality. The estimate of 10 birds to a square mile is very conservative, for in Massachusetts, where the food supply is less than in the Western States, the tree sparrow is even more abundant than this in winter. The writer has known places in Iowa where several thousand tree sparrows could be seen within the space of a few acres. This estimate, moreover, is for a single species, while, as a matter of fact, there are at least half a dozen birds (not all sparrows) that habitually feed during winter on these seeds. Farther south the tree sparrow is replaced in winter by the white-throated sparrow, the white-crowned sparrow, the fox sparrow, the song sparrow, the field sparrow, and several others; so that all over the land a vast number of these seed eaters are at work during the colder months reducing next year's crop of worse than useless plants.

Junco hyemalis.

Spizella monticola.

Zonotrichia albicollis.

Zonotrichia leucophrys.

Passerella iliaca.

HOUSE FINCH

Of all the sparrow groups, there is probably no member, unless it be the exotic form known as the English sparrow, that has by reason of Its food habits called down so many maledictions upon Its head as the house finch, red head, or linnet, as it is variously called. This bird, like the other members of its family, is by nature a seed eater, and before the beginning of fruit raising in California probably subsisted upon the seeds of weeds, with an occasional taste of some wild berry. Now, however, when orchards have extended throughout the length and breadth of the State and every month from May to December sees some ripening fruit, the linnets take their share. As their number Is legion, the sum total of the fruit that they destroy is more than the fruit raiser can well spare. As the bird has a stout beak, it has no difficulty in breaking the skin of the hardest fruit and feasting upon the pulp, thereby spoiling the fruit and giving weaker-billed birds a chance to sample and acquire a taste for what they might not otherwise have molested. Complaints against this bird have been many and loud, more especially in the years when fruit crops first came to be an important factor in the prosperity of the Pacific coast. At that time the various fruits afforded the linnets a new and easily obtained food, while cultivation had reduced their formerly abundant supply of weed seed. When the early fruit growers saw their expected golden harvest suddenly snatched away or at least much reduced in value by the little marauders, it is no wonder that they were exasperated and wished to destroy the authors of the mischief.

Passer domesticus.

Carpodacus mexicanus frontalis.

In order to test the matter thoroughly and ascertain whether these birds ate any other kind of food that might to some extent offset the damage inflicted upon the fruit, the horticulturists and ornithologists of California were requested to secure a number of the stomachs of these birds and send them to the Biological Survey. An agent was also sent to the fruit-raising sections, who watched the birds in the orchards and collected a number of them. In this way 1,206 stomachs were obtained and carefully examined, and the result shows that animal food (insects) constituted 2.44 per cent and vegetable food 97.56 per cent of the stomach contents, not counting gravel.

So small a proportion of animal food can not, of course, mean a great destruction of insects. As these stomachs were collected in every month, with the greater number taken during the summer, it is evident that whatever good one may expect from the linnet must not be looked for in this direction. Unlike most of the sparrow family, the linnet does not feed its young upon Insects to any great extent. The contents of the stomachs of a number of nestlings were carefully examined, and the only animal food was found to consist of wooly plant lice. These also constituted the great bulk of the animal food eaten by adults.

The vegetable food of the species consists of three principal items--grain, fruit, and weed seeds. Grain amounts to less than 1½ per cent in August, which is the month of greatest consumption, and the average for the year is a trifle more than one-fourth of 1 per cent. Fruit attains its maximum in September, when it amounts to 27 per cent of the whole food, but the average for the year is only 10 per cent. The seeds of weeds constitute the bulk of the diet of the linnet, and in August, the month of least consumption, amount to about 64 per cent of the food. The average for the year is 86 per cent.

From the foregoing it is evident that whatever the linnet's sins may be, grain eating is not one of them. In view of the great complaint made against its fruit-eating habits, the small quantity found in the stomachs taken is somewhat of a surprise. But it must be remembered that the stomach contents do not tell the whole story. When a bird takes a single peck from a cherry or an apricot, it spoils the whole fruit, and in this way may ruin half a dozen in taking a single meal. It is safe to say that the fruit pulp found In the stomach does not represent more than one-fifth of what is actually destroyed. That the linnets are persistent and voracious eaters of early fruits, especially cherries and apricots, every fruit raiser hi California will bear testimony. That the damage is often serious no one will deny. It is noticeable, however, that the earliest varieties are the ones most affected; also, that in large orchards the damage is not perceptible, while in small plantations the whole crop is frequently destroyed.

THE GRACKLES.