CALENDAR OF ORNITHOLOGY FOR 1849 . 
or inducing them to prolong their departure ; in this country, how- 
ever, though a cold autumn has an evident effect on the time of 
the departure of the swallows, and many of our summer birds, a 
mild spring does not always hasten the departure of the winter 
visitants. The arrival of some summer birds, as the wheatear, does 
not seem at all influenced by the mildness or continued severity of 
the spring here ; but we have observed, that mildness and advance 
of vegetation in this country, does make a difference in the time of 
appearance of several species, particularly the Sylviadm ; and it 
may be asked, whether the progression of these and others from 
Southern Europe and Africa is gradual, advancing with the seasons ? 
The laws which regulate the migratory zone of some species, are 
not probably applicable to such as appear to start at once and fly 
to their destination. The great mass of swallows depart from this 
country at once, but the appearance of their numbers is somewhat 
more gradual. The Sylviadce appear gradually. The migratory 
tlirushes again, come and depart at once. So also do the snipes, 
woodcocks, and others of the Scolopacidce. If resident on or near 
the sea-coast, attention should be paid to the ornithology after 
remarkable storms, particularly during March and April, October 
and November; and both on the coast and inland, during these 
months, when migration takes place, and the young are leaving their 
breeding places and congregating, many rare species have been met 
with, driven out of their ordinary tract ; and vast flocks of species, 
geneially few in number, sometimes in the same way appear, show- 
ing the influence, climate or the seasons may have in the distribu- 
tion of animal life. On the coast, it is also curious to mark the 
habits of the different sea- fowl previous to, or after the occurrence 
of a storm, or any marked change in the weather. 
Independent of regular migration, by which we mean the arrival 
of some birds (not at other seasons found in our islands) in spring, 
foi the purpose of incubation, and then remaining with us during 
the summer months; or the arrival of some birds in late autumn 
rom another county, and remaining during the winter months, 
apparent y to enjoy a larger supply of food and a milder climate, 
not afforded by their more northern summer quarters ; there are 
urge accessions made to the numbers of some permanently resident 
birds, either altogether from another country, or by a partial migra- 
tion from one locality to another temporarily more suitable. " In 
