3°6 
THE LIVING WORLD. 
“ The cause of this curious habit is difficult to discover. It has been suggested 
that the hereditary impulse to leave its breeding grounds so early originally 
obliged it to abandon the education of its young to strangers; but the same 
habit is found 
in many species 
in India and Af¬ 
rica, which are 
resident and do 
not migrate. 
Others have at¬ 
tributed it to 
the polygamous 
habits of the 
cuckoo , but the 
cuckoo is not 
polygamous, it 
is polyandrous; 
the males are 
much more nu¬ 
merous than the 
females, and the 
sexes do not pair 
even for a sea¬ 
son. It is said 
that each male 
has its own feed¬ 
ing grounds, 
and that each 
female visits in 
succession the 
half dozen 
males who hap¬ 
pen to reside 
in the neighbor¬ 
hood. A more 
plausible ex¬ 
planation of the 
peculiar habits 
of the cuckoo is 
to be found in 
the fact that 
its eggs are laid 
at intervals of 
several days, 
great toucan. and not, as is 
usual, on suc¬ 
cessive days. . Very satisfactory evidence has been collected that the cuckoo 
lays five eggs in a season, and that they are laid at intervals of seven or eight 
days. The American cuckoo and many of the owls very often do the same. 
