INTRODUCTION. 
V 
appearance, together with a host of other sylvan species ; soon after, the Cuckoo and Landrail arrive ; and 
on the joyous First of May the latest of all comers, the Swift, the Nightjar, and Flycatcher may be looked 
for. A pause of a few weeks follows ; and, reproduction having been accomplished, then commences, as it 
were, the ebb of the great tide of migratioti. The Swift, which, as we have seen, was one of the latest to 
arrive, is the first to depart ; then the Landrail makes good its retreat to the more southern country of 
Africa ; other kinds follow in succession, all hastening to make their escape before such changes of climate 
and natural conditions have set in as would prove fatal to their existence, either on account of the lowering 
of the temperature or the cessation of suitable food. By tbe end of September the great mass have departed, 
and only a scanty remnant are to be met with. With this same ebb, the autumnal months bring to our sight 
again strings of grallatorial and natatorial birds, urged by similar causes from the northern regions back 
tow'ards the south in search of that food and aquatic life which the icy hand of winter had already begun to 
grudge them and their progeny in their summer location. To follow the sun appears to be the course of 
true migration ; but the promptings of Instinct which lead the Swallow and many other species to quit our 
shores, after a brief sojourn, for Africa, or those which lead the Fieldfare and the Redwing to quit the 
Norwegian ‘fjelds’ for our cultivated lands, must surely be connected in some way with, if they have not 
for their sole object, the provision of food and climate suitable to the species. The Rev. H. B. Tristram 
remarks that “ those species which have the most extended northerly have also the most southerly range, 
and that those which resort to the highest latitudes for nidification also pass further than others to the south- 
ward in winter. Thus the migratory Fieldfare and Redwing, visiting regions north of the limits of the Thrush 
and Blackbird, on their southern migrations likewise leave their more sedentary relatives behind. The 
Brambllng, which passes the Chaffinch in Norway, leaves it also in Europe, and crosses the Mediterranean 
every winter to the Barbary states.” — Ibis, 1865, \|). 77. 
The regularity, however, which occurs in the arrival of our summer visitants is not quite so strictly adhered 
to in their departures. Having accomplished the purpose for which they came, these depart again at varying 
periods, but mostly as soon as the renewal of their primaries will admit of their flying across the channel, 
leaving their young to follow instinctively (when their muscular development has been sufficiently matured) 
the same route by which their parents have preceded them. This apparent desertion of the young birds at 
a period when one would imagine the presence of their parents as leaders would be absolutely essential, 
seems to prevail amongst many of our migratory species. That the old birds shotdd be able Instinctively to 
wing their way back to whence they came is not half so marvellous as that the newly fledg'ed nestling, urged 
by some mysterious power, should undertake a flight extending over hundreds of miles and many variations 
of climate in searcn of a temporary home it has never seen. This irresistible impulse, which prompts the 
necessity of a migration somewhither, is but too sadly seen in the restless actions and almost frantic efforts 
c 
