Most species of the smaller birds which nest in hollow trees, and
therefore in bird houses, suffer seriously from intrusion by English
Sparrows and European Starlings. These two species, nesting in similar
locations and being prolific, tend to take up all available nesting
cavities, even ejecting native birds which have built or begun to build.
This condition, already serious, may become far more baneful than we are
as yet able to realize. It may even contribute to the eventual
extinction of Bluebirds, Crested Flycatchers, and Purple Martins unless
we provide nesting sites sufficient in number and suitable in kind for
all. The number of natural nesting sites is already far below that
required by these birds, and yet the Starlings in particular are
increasing alarmingly. There is no way to determine when a final
adjustment or balance will be reached or what the numerical status of
our native bird-house dwellers will be when such balance shall have been
attained.
In the case of the native species named above, we can at least help by
providing proper nesting boxes which will induce the birds to
concentrate about our houses, where the European Starling and the
English Sparrow menace may be more easily and effectively met than
elsewhere. The reader should note that the imported English Sparrow,
which is in reality a weaver finch and unrelated to our tuneful native
sparrows, is the only "sparrow" east of the Rocky Mountains that nests
in holes or bird houses. The shyer, more desirable, native species are
invariably harmless and should be both protected and encouraged.
The smaller of the bird-house species, such as the House Wren, Tree
Swallow, Black-capped Chickadee, White-breasted Nuthatch, and Tufted
Titmouse are less affected by the intruders. These smaller birds can
use, and usually select, cavities with openings too small for either
Starling or English Sparrow to enter. However, there is still a distinct
practical advantage in providing proper boxes for House Wrens and other
small species. In many instances these birds fail to find places safe
from the ubiquitous English Sparrow and European Starling, which then
proceed in their well-known manner to work destruction. A properly made
wren house, chickadee house, or swallow house can be absolutely safe
from the foreign invaders.
More nesting sites, properly made and situated, are desirable, owing to
the destruction of birds' traditional nesting sites over wide acreages
about cities and other settled areas, but the providing of suitable bird
houses needs no defense or excuse. Whether it be the beautiful and
demure bluebird, "bird of happiness," the sleek and immaculate swallow,
the songful wren, "saucy and impudent," the bustling and industrious
chickadee, or the alert and noisy flycatcher, the native tenant of the
bird house will be an interesting and entertaining neighbor, always
prompt to pay his rent in one form or another or in many forms and with
interest. Does one need any special excuse for offering hospitality to
such a neighbor? When birds nest on our home grounds, their destruction
of garden pests, mosquitos, gnats, and other undesirable insects is
concentrated where we can most directly profit from the results--our own
greater comfort and safety, better gardens, more productive orchards,
more verdure in shade trees and in ornamental trees and shrubs.