350 
ON INSTINCT. 
The order in which they appear and disappear is really won¬ 
derful ; and what is very remarkable, inasmuch as it shews 
the combination of reason with instinct, those which absent 
themselves at stated periods, such as the swallow, for instance, 
return annually to the same spot to build their nests. It is a 
commonly received opinion, that these migrations are produced 
through a failure of food, or a cold temperature of the air ; but 
seeing that many of them disappear in the summer season, when 
food is placed before them in the greatest plenty, we must seek 
for some other cause. The late Dr. Jenner informs us, in his 
Observations on the Migration of Birds,that the influence 
which incites them to migrate is produced by the preparation 
which nature is making by a new arrangement in the structure 
of the sexual organs—the enlargement of the testes in the male 
and the ovaria in the female. Here, then, is another remarkable 
example of instinct, following the development of the organiza¬ 
tion, proving that the migratory propensities of birds is not the 
result of instruction, nor of observation and expeiience, but the 
action of some external agency upon the organization, which is 
fitted by the omniscient Creator to respond to its action. These 
birds are directed to our shores at a certain season of the year 
to produce and rear their young. This appears to be the grand 
intention which Nature has in view; but their presence here may 
answer many secondary purposes,—among these, they are un¬ 
doubtedly sent to cheer the heart of man. Nature never gives 
one property only to the same individual substance. Through 
every gradation, from the clod we tread upon to the glorious sun 
which animates the whole terrestial system, we may find a vast 
variety of purposes for which the same body was created. If 
we look on the simplest vegetable, or the reptile it supports, 
how various, yet how important in the economy of Nature, are 
the offices they are intended to perform! 
the day, but the greater number in the night, particularly by moonlight; while 
the fieldfare, gannet, snipe, jack-snipe, curlew, and bean-goose, arrive from 
their northern summer haunts. 
In October^ the window-swallow, the bank-swallow, red-start, fly-catcher, 
landrail, sandpiper, redshank, and hawk-owl, depart for more southern lati¬ 
tudes; whilst the woodcock, redwing, wood pigeon, hooded-crow, shoveller, 
greyleg, teal, and merlin, arrive on our shores from the north. 
In November, the golden-plover, poacher, gadwal, widgeon, Bohemian 
wax-wing, golden-eyed duck, and the stock-dove, arrive from the north, or 
from the more mountainous part of the country. 
In December, the snow-fleck, hawfinch, Sarcelle duck, tufted duck, wild 
swan, lumme, cobble, velvet duck. Eider duck, goosander, and merganser, 
arrive on our coasts more or less regularly according to the severity or rnild- 
jiess of the weather; whilst the grey lapwing departs southward. 
