[24] 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[25] (fig. 9), chipping sparrow,[26] and field sparrow[27]
(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.
[25] _Melospiza melodia_.
[26] _Spizella passerina_.
[27] _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.
[Illustration: Fig. 9.--Song sparrow. Length, about 6½ inches.]
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.
[Illustration: Fig. 10.--Field sparrow. Length, about 5½ inches.]
The snowbird[28] and tree sparrow[29] 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,[30]
the white-crowned sparrow,[31] the fox sparrow,[32] 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.
[28] _Junco hyemalis_.
[29] _Spizella monticola_.
[30] _Zonotrichia albicollis_.
[31] _Zonotrichia leucophrys_.
[32] _Passerella iliaca_.