THE PRESIDENTIAL ADDRESS. 13
the first sub-family, the Turdinae, we at once become hopelessly per-
plexed. Here we have :—
Mistle Thrush,—Resident and increasing species. Breeds from Norway to N.
Africa. Migrates to N. India, Persia and Sahara.
Song Thrush.—Resident with us, but notoriously migrant on the Continent (see
the interesting account of the "Chasse aux Grives" in Gould's "Birds
of Great Britain" and the 4th edition of Yarrell). Breeds from 60° N.
eastward to Pacific and to Pyrenees, North Italy, and Caucasus.
Migrates to N. Africa and Persia.
Redwing.—Migratory to North Africa. Breeding in Norway, and even Anhalt,
but not here.
Fieldfare.—Later arrival than Redwing. Migratory to N. Africa and N. India,
Breeding in Scandinavia, Central Germany, and probably in Alps and
Pyrenees, but not here.
Blackbird.—Resident and autumn migrant. Like the Mistle Thrush has spread
northward and westward of late years owing to increase of plantations.
Breeds from 67° N. to N. Africa and Asia Minor.
Ring Ouzel.—Only Thrush entirely absent from Britain in winter. Breeds from
58° N. to Pyrenees and Sierra Nevada of Spain, and N. Africa. Migra-
tory to N. Africa, Lower Egypt, Syria, and Persia.
Finding three resident species, two winter migrants and one
summer migrant, and knowing what we do of the habits of these
Thrushes, the facts prove conclusively that the absence of necessary
food is not the cause of migration. A little reflection on the habits
and distribution of the Nightingale, Woodcock, Quail, Landrail, and
many other birds leads to a like conclusion. How can we thus ex-
plain the departure of the Redstart just when its rarer congener the
Blackstart is arriving, but only to stay with us until the commoner
species again returns. The Grey Shrike arrives when the Red-
backed species is leaving us. The same apparent diversity of habit
happens with the various species of Wagtail appearing at alternate
seasons.
The late Edward Newman thought migration the simplest thing
in the world. In his "Letters of Rusticus" he says, "At certain
periods of the year the proper food of certain species of birds fails in
the native countries of these species ; this is the 'cause' of migra-
tion : then the first law of migration is the instinctive—and perhaps in
some instances experimental—knowledge that proper food is about
to fail. * * * No sooner does spring return, and promise abund-
ance of food, than all the feathered tribes return northward, to dwell
and to rear their young in the very places where they themselves
were reared."23 True, but why is this ? here is the crux. That an
23 "Letters of Rusticus," 1849, pp. 10 and 11.