380 
BIRD-LIFE. 
journey, though they leave but slowly at first. The 
“ passage” is at its height at about the vernal equinox, 
and lasts into May, when those which left us the earliest, 
return, thus terminating the migration which they had 
begun; for the spring “ flight” is the reverse of the 
autumn one in all its details. 
Birds wander to the south and south-west, and return 
from the same direction. Their winter quarters are 
widely dispersed, embracing even entire countries, the 
ultimate resting-places of many species, however, still 
remain a riddle; thus, as yet, no one has been able to 
determine where our pretty Swallows hibernate. 
It is true that the common Swallow and House Martin 
have been met with in almost all parts of Southern and 
Western Africa, though as far as I know their true winter 
residence has not yet really been discovered. We learn from 
trustworthy naturalists that the first-named species appears 
every winter in India, remaining there until the spring, 
and that the Martin also is occasionally found there at 
the same season : it is very doubtful, however, that these 
two species should have migrated from Europe to India, but 
much more probable that they come from Northern Asia. 
My observations in North-eastern Africa have led me to 
consider the winter residents of the Nile countries as 
being almost all natives of Eastern Europe and North¬ 
western Asia ; other experiences, gathered in Spain, and 
which entirely coincide with the former, lead me to 
believe that birds of passage do not converge from all 
sides to one place, but rather the different migrations 
form columns, each pursuing a course parallel to the rest. 
Thus it would result that all Old World birds of passage 
would fly to countries lying in a south-westerly direction 
from their home, and consequently those bred in the east 
