210 THE ZOOLOGIST. 
more variable than the wind—nothing more variable than the wind 
during the vernal and autumnal equinoxes, when birds must 
migrate—blowing, as it does, from every point of the compass in 
twenty-four hours. Were the birds’ movements mainly dependent 
on air-currents, and air-currents only, we should rarely—although 
Mr. Rowley assumes the contrary—have year by year the same 
phenomena occurring at any given locality on our east coast. The 
arrival or non-arrival of immigrants being dependent on one of the 
most variable of causes, the results would also be variable, whereas 
the contrary is the case. 
Wind, I am convinced, except in some very abnormal in- 
stances,* as great gales and storms, has little to do with the 
normal phenomena of migration. All animals and man himself 
undoubtedly prefer favourable weather for travelling; but although 
they may delay, they do not put off their travels altogether because 
wind and weather are unpropitious. 
Continuing his subject, Mr. Rowley says there is one thing in 
common between the migration of the seed and the bird—* once 
started they do not come back till the journey is finished.” Does 
Mr. Rowley seriously wish it to be inferred that any comparison 
can be drawn between the two phenomena—the one thing an 
inert mass, the play of wind and current; the other a living, 
highly endowed organism. The seed returns not by the same 
path because it cannot, the bird because it will not. Birds 
are occasionally, however, known to turn back in their migra- 
tory journey when they find they have made a mistake. Several 
instances are on record of migrants during the autumn being 
seen away off the mouth of the Channel and over the Atlantic, 
apparently migrating in the wrong direction: they are probably 
such as on dark foggy morning have overshot the mark, and at 
daylight discovering their error, are making their way to the 
nearest land. 
There is also the case mentioned by Mr. Stevenson (‘ Birds ot 
Norfolk, vol. i., p. 413 et seg.) of the Red-legged Partridges in 
Norfolk migrating out to sea and again returning. Had the birds 
in these instances migrated on Mr. Rowley’s theory, and not by 
their own instinct, they ought to have kept going in a direct line 
without coming back. In fact, on Mr. Rowley’s hypothesis, we 
* See ‘ The Field,’ March 11th and 18th, 1876, “On some Abnormal Migrations 
of Birds.” 
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