der
mandible. By this rubbing of the head and neck it is easy to
perceive how birds can oil these parts if it be allowed that birds
oil themselves at all.

I cannot see how we can explain this action of birds in relation
to any other object. It certainly does not seem calculated to
expel or disturb any vermin lodged there, and I remarked that it
never occurred except when the bird had been applying its bill to
the gland as above mentioned. However, Mr. Waterton, and anyone
who doubts this oiling, may readily judge for themselves. Let them
take a common duck, and shut it up for two or three days, so that
it can have no access to water except for drinking, and at the end
of that time let them turn it out, and allow it to go to a brook
or pond; it will give itself a thorough ablution--ducking, diving,
and splashing with its wings--and on coming out, will begin to
dress and arrange its feathers, very frequently applying its bill
to the gland on its rump. If this application is not for the
purpose of procuring a supply of oil, perhaps Mr. Waterton will
have the goodness to inform us what it is for, and what end this
gland answers in the economy of the feathered tribes if not that
which has hitherto been supposed. (June 30, 1832.)

* * * * *

MOCKING POWERS OF THE SEDGE-WARBLER.

In the article "Sedge Bird," in Montagu's "Dictionary of
Ornithology" (Rennie's edition, p. 455), the writer says: "It has
a variety of notes, which partake of those of the Skylark and the
Swallow, as well as the chatter of the House-Sparrow." According
to my observation, it has a much greater variety than this. I have
heard it imitate in succession (intermixed with its own note,
_chur, chur_), the Swallow, the House-Martin, the Greenfinch, the
Chaffinch, the Lesser-Redpole, the House-Sparrow, the Redstart,
the Willow-Wren, the Whinchat, the Pied-Wagtail, and the Spring-
Wagtail; yet its imitations are chiefly confined to the notes of
alarm (the fretting-notes as they are called here) of those birds,
and so exactly does it imitate them in tone and modulation, that
if it were to confine itself to one (no matter which), and not
interlard the wailings of the little Redpole and the shrieks of
the Martin with the _curses_ of the House-Sparrow, the _twink,
twink_ of the Chaffinch, and its own _care-for-naught_ chatters,
the most practiced ear would not detect the difference. After
being silent for awhile, it often begins with the _chue, chue_ of
th