TRANSACTIONS OF SECTION D. 1099 
many of these may be traced to the laws which regulate the movements of animal 
economy and directed by their constitutional impulses, as one class of birds seeks 
more genial climates before the approach of winter, and where their food supplies 
can be obtained, and on the other, when the storms and frost of winter have been 
removed, those wandering world-wide citizens find fields and pastures new. It 
is only their first appearance that can be noticed and noted with care, and thus 
form an index of their certain movement, and that times and season are not 
things of chance. Although they make their appearance under different surround- 
ings, their departure is not so easily noticed because in some cases they leave one 
by one, or in small flocks, and if like the lapwings, the birds old and young gather 
from July to October into larger and larger flocks of several hundreds, and perhaps 
seen to-day and to-morrow all have left, without any apparent cause either of 
food or climatic conditions. Their spring and autumn movements are like their 
eall-notes, breeding-notes, or song-notes; they are constitutional, and manifest 
themselyes when required. We might as well say it is instinct that causes a 
flower to bloom and assume its natural and inherent colours; the impulses are 
constitutional, and manifest themselves from earliest life; they are not simple 
but compound, connected with their physical and procreative functions relating to 
each animal’s life-history and worked into their brain system, and thus become 
reproduced, in successive generations it becomes stereotyped, so that in most 
cases external influences have little or no effect, either to cause or retard these 
migratory movements. ‘True, these outward conditions may quicken or lengthen 
these movements, but they can neither stop nor arrest them, and even by their de- 
structive influence lessen their number, as under favourable conditions may increase 
them. And this is true in migratory birds in all parts of the world when their lines 
of migrations can be traced. Many years ago, when passing through these 
migratory lines in Arctic seas, we have observed them in their long journeys to their 
breeding and feeding grounds, both in spring and on their return south in autumn, 
from the small red-polled linnets, Linaria borealis. Gould, the snow bunting, Plectro- 
phanes nivalis, Linn., and the Lapland lark bunting, P. Lapponica, Seb., and also the 
large birds both land and sea, such as the peregrine falcon, the cormorant, Phala- 
crocorax carbo, Steph. It is a well-known fact that many of the smaller land birds 
are caught in the rigging of ships, and some of the larger if the storm of snow or 
rain with frost continues sufficiently long, the cause of which is frozen ice or snow 
that accumulates on their feathers so much increasing their weight that flight 
becomes impossible, and they perish and vast numbers die. Again, in aquatic 
birds the cause is different from that. During a snow storm they lose the ice-coat, 
from whatever cause they from their low mode of flight under such often travel far 
on the land, and strike against objects and thus perish, to be understood from the 
accounts of lighthouses and ships. In our temperate climate one of the chief causes 
of delay and loss of life among migratory birds is rain and wet misty fog, the 
one a storm of wind and rain, the other a long continuance of dull foggy mist when 
almost everything is invisible, the birds become weighted by the accumulation of 
water on their feathers, so that they find it impossible to continue their flight, sink 
down from exhaustion in the sea, perish on the land, die from exhaustion and want 
of food. One fact well known is, that during foggy weather the young jackdaws 
and hooded crows are caught in large numbers, because when once wetted with 
dew they cannot rise. It is often by this means that the arrival of our migratory 
birds is delayed, but at the same time it is remarkable how little difference there 
is, taking one year with another. Climatic causes tend from accident to diminish 
their number rather than affect the regularity of their visits. Another point of 
equal importance is their departure, but the means of ascertaining it is more 
difficult, because some birds move in large bodies, while others move in small 
flocks. If these remarks give any interest to the subject of the arrival and depar- 
ture of our migratory birds over the country, it in time will add much to our 
knowledge of their life-history and habits. 
