476 REPORT—1896. 
‘ancentive to migration ; but that (2) its force is certainly an important 
factor, inasmuch as it may make migration an impossibility, arrest to a 
greater or lesser degree its progress, or even blow birds out of their 
course. We have the clearest proof, indeed, that birds do not emigrate 
when the winds are exceptionally high, though they sometimes pass into 
high winds and gales when en route, under the meteorological conditions 
which have already been described and explained. Ordinary winds—that 
is, winds not too strong—appear to be of small concern to the birds, for 
they are recorded as migrating with winds blowing from all quarters. 
It is, however, a fact that particular winds almost invariably prevail 
during the great autumnal movements, and these have hitherto been con- 
sidered by some as the direct incentives to such migrations. Such is not the 
case, and it may be at once stated that these supposed favourable breezes 
are simply another direct result of the pressure distribution favourable 
to the movements. This peculiar type of weather has already been fully 
described and its effects discussed ; the winds prevailing and dependent 
upon these barometric conditions are easterly, chiefly south-easterly 
breezes. There is really no reason why westerly (west, north-west, and 
south-west) winds, not too strong of course, should not, other things being 
equal, be in every way as suitable for migratory movements as those 
varying between such divergent points as north-east to south. When, 
however, we come to inquire into the meteorological conditions producing 
these westerly winds, the reason for their unsuitability becomes at once 
apparent. These winds are the result of types of pressure-distribution 
which are fatal to migration between north-western Europe and Britain, 
namely, the presence of cyclonic areas to the north-east or east of the 
British Isles. This means that the area under disturbed conditions would 
be the very region from which we derive our autumn immigrants and 
render emigration from such sources impossible. Such areas of disturb- 
ance, with their high westerly and north-westerly winds, indeed, often 
extend to and influence the weather in our Islands, and interfere with 
the British emigratory movements in both autumn and spring. 
Strong winds have a curious effect on the flight of Gulls, compelling 
them to move in a direction more or less directly heading the wind. Thus 
a strong westerly wind causes great numbers of Gulls to seek the estuaries 
and bays of our east coast. On the other hand, strong easterly winds 
will fill the estuaries and sea-lochs of the west coasts with these birds. 
The lee side of islands is also sought under similar conditions of the 
wind. A south-easterly wind, for the same reason, causes considerable 
numbers of Gulls of various species to pass southward along the eastern 
coast of Britain. Large parties of Gulls are also recorded as passing N.— 
sometimes for a whole day—-with a N.N.W. wind. These movements are 
more or less local, and the birds return, no doubt, to their regular haunts 
in a few hours’ time. They are, moreover, chiefly observed in the autumn. 
Gales.—One effect of gales has already been alluded to, namely, that 
they arrest or make impossible the migratory movements. 
At sea, however, they have a direct influence on the migrations of 
certain marine species, such as Skuas, Phalaropes, Petrels, &c. These 
birds in the autumn are occasionally driven out of their course by severe 
gales, and appear on our coasts in exceptional numbers. At such times, 
indeed, they are often blown far inland. Later in the season (in winter) 
Guillemots, Razorbills, Puffins, and Little Auks, are in like manner 
swept from their winter retreats on to our shores. Some of these last- 
