ECONOMIC RELATIONS OF OUR BIRDS. 
455 
has for its natural abode the wild grass swamps so common in many parts cf 
the country, and from there, when it becomes excessively abundant, it marches 
out upon fields of grass and grain in such vast columns as to sweep everything 
green before it. The army-worm j^ear of 1861 will long be remembered. Tl:e 
Rocky Mountain Locust is another insect of the same kind. 
Viewed in the light of such facts as these, insectivorous birds which rear their 
young in such uninviting places, and where they appear to lead useless lives, 
shine with a new interest to us; and even though they may be somewhat de¬ 
structive, they should be protected until careful study proves that they do not 
feed upon the army-worm or other pests. Some of the birds which frequent 
these situations ai’e the Marsh and Short-billed Wrens, the Swamp Sparrow, 
several of the Blackbirds, the Bobolink, the Rails, as well as other birds. 
The situation in which the nest is placed has much to do in determining the 
abundance of the species, especially in cultivated districts, and consequently its 
general usefulness. The Short-billed Wren often builds in our low, wet meadows, 
but its breeding season is not fully past when haying-time begins, and many a 
nest freighted with eggs or young is mown down and its contents destroyed. 
The result is, that it is far less abundant than its cousin, which selects more 
secure breeding jdaces. The Short-billed Wren cannot, thei-efore, be offered as 
a substitute for the troublesome Redwing, or for the Bobolink, both of which 
breed in similar situations, but which get their young upon the wing before the 
grass is re ady to cut. 
Birds, like plants, may be out of place, and so more injurious than they would 
be if confined to their proper si)heres. Blue Jays and Shrikes have no right in 
orchards and about dwellings during the breeding season, unless more useful 
birds cannot be induced to tarry there. 
(7) TJie haunts of the birds. The places which a bird frequents during the 
season, though always including the place where it nests, are often much more 
varied and extensive. Upon these haunts, as upon the breeding places, depend 
much of the bird's usefulness or injury. All of our Thrushes, so far as food 
and method of obtaining it are concerned, have essentially the same habits as 
the Robin, but none of them are, at present, as useful to agricultural or horti¬ 
cultural interests as it is. Sliould any of them in the future become as familiar 
as the Robin, tliey will doubtless approximate it in usefulness. 
(8) The time of day at which the bird obtains its food. Nocturnal insectiv¬ 
orous birds and those which feed in the early twilight are especially to be 
encouraged, not because they are necessarily more destructive to insects than 
other birds, but because they feed at a time when insects are abroad in abun¬ 
dance and when they have but comparatively few enemies with which to con¬ 
tend. Rapacious birds, however, which obtain their food at night are to be 
regarded with more suspicion, perhaps, tlian those which fiy by day. All the 
Owls, provided with their peculiar plumage, are able to move so noiselessly, 
that, under the cover of night, when other birds are in repose, they may be 
expected to exert a i^owerful influence in reducing the abundance of birds, 
especially of the woodland species. 
(9) The method by ichich the bird obtains its food. 
(10) The situation in ichich the bird obtains its food. 
(11) Whether or not thebird does an important ivork ichich other birds are not 
fitted to do. 
These are questions of extreme importance, especially if it is proposed to ex¬ 
tirpate a species, or to reduce its abundance. Tliere is such a division of labor 
among birds, that, as has been said, there are very few insects indeed which may 
