. By a
very little persuasion with our finger-tip the division readily yields,
and we discover the summit of the nest to be a mere rim--a top story, as
it were--with a full-sized nest beneath it as a foundation. Has our
warbler, then, come back to his last year's home and fitted it up anew
for this summer's brood? Such would be a natural supposition, did we not
see that the foundation is as fresh in material as the summit. Perhaps,
then, the bird has already raised her first spring brood, and has simply
extended her May domicile, and provided a new nursery for a second
family. But either supposition is quickly dispelled as we further
examine the nest; for in separating the upper compartment we have just
caught a glimpse of what was, perhaps only yesterday, the hollow of a
perfect nest; and, what is more to the point of my story, the hollow
contains an egg--perhaps two, in which case they will be very
dissimilar, one of delicate white with faint spots of brown on its
larger end, the putting of the warbler, the other much larger, with its
greenish surface entirely speckled with brown, and which, if we have had
any experience in bird-nesting, we immediately recognize as the
mischievous token of the cow-bird. We have discovered a most interesting
curiosity for our natural-history cabinet--the embodiment of a
presumably new form of intelligence in the divine plan looking to the
survival of the fittest. It is not known how many years or centuries it
has taken the little warbler to develop this clever resource to outwit
the cow-bird. It is certain, however, that the little mother has got
tired of being thus imposed upon, and is the first of her kind on record
which has taken these peculiar measures for rising above her besetting
trouble.

[Illustration]

[Illustration]

Who can tell what the future may develop in the nests of other birds
whose homes are similarly invaded? I doubt not that this crying cow-bird
and cuckoo evil comes up as a matter of consideration in bird councils.
The two-storied nest may yet become the fashion in featherdom, in which
case the cow-bird and European cuckoo would be forced to build nests of
their own or perish.

But have we fully examined this nest of our yellow warbler? Even now the
lower section seems more bulky than the normal nest should be. Can we
not trace still another faint outline of a transverse division in the
fabric, about an inch below the one already separated? Yes; it parts
e