its complement of chickadees.
Of the morning's forty species, thirteen were warblers; and of these
thirteen, four were represented by one specimen each. For curiosity's
sake I may add that a much longer walk that afternoon, through the same
and other woods, was utterly barren. Except for two or three flocks of
white-throated sparrows; there was no sign whatever that the night
before had brought us a "flight."

Autumnal ornithology may almost be called a science by itself. Not only
are birds harder to find (being silent) and harder to recognize in
autumn than in spring, but their movements are in themselves more
difficult of observation. A few years of note-taking will put one in
possession of the approximate dates of arrival of all our common vernal
migrants. Every local observer will tell you when to look for each of
the familiar birds of his neighborhood; but he will not be half so ready
with information as to the time of the same birds' departure. Ask him
about a few of the commonest,--the least flycatcher and the oven-bird,
or the golden warbler and the Maryland yellow-throat. He will answer,
perhaps, that he has seen Maryland yellow-throats in early October, and
golden warblers in early September; but he will very likely add that
these were probably voyagers from the North, and that he has never made
out just when his own summer birds take their leave.

After the work of nidification is over, birds as a rule wander more or
less from their breeding haunts; and even if they do not wander they are
likely to become silent. If we miss them, therefore, we are not to
conclude as a matter of course that they have gone south. Last year,
during the early part of the season, cuckoos were unusually plentiful,
as it seemed to me. Then I discovered all at once that there were none
to be found. After the first of July I neither saw nor heard a cuckoo of
either species! Had they moved away? I do not know; but the case may be
taken as an extreme illustration of the uncertainty attaching to the
late-summer doings of birds in general. Every student must have had
experiences of a sort to make him slow to dogmatize when such points are
in question. Throughout May and June, for example, he has heard and seen
wood thrushes in a certain grove. After that, for a whole month, he
hears and sees nothing, though he is frequently there. The thrushes have
gone? So it would seem. But then, suddenly, they are singing again in
the very same trees,