REV. W. SERLE ON MIGRATION OF BIRDS. 139 
MIGRATION OF BIRDS. 
By Rev. W. Serie, M.A, B.D., M.B.O.U. 
(Read 9th January 1902.) 
Marcu and October are perhaps the two most important 
months in the ornithological calendar. At these seasons 
migration in all parts of the world is at its height. In 
March the singing birds that had been making Africa and 
India their winter home, and the waders that had tenanted 
the marshes of the Upper Nile or had distributed them- 
‘selves over the sea-shores of the South Pacific, become pos- 
sessed of a mysterious influence that drives them northwards 
into the woods of temperate regions or to the bleak tundras 
of northern Siberia; whilst the harmless wrens and the pip- 
ing plovers that had been rearing their broods—the former 
amid the tangled growths of Terra-del-Fuego, the latter on the 
shores of southern seas—retreat before the rigours of winter 
up the Chilian coast to the milder regions of South America, 
In October the order is reversed. As soon as the first snows 
cast their mantle of whiteness over the dreary waste, or the 
nipping night-frosts destroy the insect-life of the forest, cer- 
tain birds move south in flocks of thousands. The flight 
has been mostly in the night-time, and we only know of it 
by seeing an extra number of familiar birds gathered along 
the hedgerows and showing little inclination to fly, so 
thoroughly exhausted are they. In southern Chili the 
‘German colonists welcome their harbingers of summer with 
the same feelings of pleasure as we do the cuckoo or the 
swallow. 
Of course this grand movement of birds is not shared in 
by all. There is a region lying on both sides of the Equator 
—the Tropical region—where such movements are not so 
evident unless at the dry and rainy periods. The climate, 
on the whole, is equal in these quarters; the landscape is a 
‘continuous monotonous green; and the birds that have adapted 
themselves to these lands, and to the various kinds of tropi- 
