nstructed than we find them now. Such is a cuckoo's
nest, such a mourning dove's or a heron's; merely a flat platform of a few
interlaced twigs, through which the eggs are visible from below. Why, we
ask, are some birds so careless or so unskilful? The European cuckoo, like
our cowbird, is a parasite, laying her eggs in the nests of other birds;
so, perhaps, neglect of household duties is in the blood. But this style
of architecture seems to answer all the requirements of doves and herons,
and, although with one sweep of the hand we can demolish one of these
flimsy platforms, yet such a nest seems somehow to resist wind and rain
just as long as the bird needs it.

Did you ever try to make a nest yourself? If not, sometime take apart a
discarded nest--even the simplest in structure--and try to put it together
again. Use no string or cord, but fasten it to a crotch, put some marbles
in it and visit it after the first storm. After you have picked up all the
marbles from the ground you will appreciate more highly the skill which a
bird shows in the construction of its home. Whether a bird excavates its
nest in earth or wood, or weaves or plasters it, the work is all done by
means of two straight pieces of horn--the bill.

There is, however, one useful substance which aids the bird--the saliva
which is formed in the mucous glands of the mouth. Of course the first and
natural function of this fluid is to soften the food before it passes into
the crop; but in those birds which make their nests by weaving together
pieces of twig, it must be of great assistance in softening the wood and
thus enabling the bird readily to bend the twigs into any required
position. Thus the catbird and rose-breasted grosbeak weave.

Given a hundred or more pieces of twigs, each an inch in length, even a
bird would make but little progress in forming a cup-shaped nest, were it
not that the sticky saliva provided cement strong and ready at hand. So
the chimney swift finds no difficulty in forming and attaching her mosaic
of twigs to a chimney, using only very short twigs which she breaks off
with her feet while she is on the wing.

How wonderfully varied are the ways which birds adopt to conceal their
nests. Some avoid suspicion by their audacity, building near a frequented
path, in a spot which they would never be suspected of choosing. The
hummingbird studs the outside of its nest with lichens, and the vireo
drapes a cobweb curtain around her fai