Song Birds and Water Fowl 
normal conduct is in a structural peculiarity 
found in none other of our familiar birds. 
If Nature ever devised a scheme that should 
bewilder her own creatures, we may be sure 
she did it in the present instance ; for the poor 
cuckoos find themselves in a dilemma that baf- 
fles instinct itself. Other birds lay their full 
complement of eggs, usually about five, on so 
many successive days, and immediately pro- 
ceed to incubate. But with the cuckoos, by 
some natural derangement of the oviparous 
apparatus, several days often elapse between 
successive depositions. If she knew how many 
eggs to expect she would probably postpone 
sitting. In that case, however, those first laid 
might possibly become stale. But her arith- 
metic is at fault, or else she is confused by the 
delay, and, after laying one or two, and finding 
that none follow, she does the best she knows 
how and begins to sit. Later another egg is 
deposited, then another, and possibly a third, 
at intervals of several days. As a result, the 
eggs begin to hatch at corresponding intervals. 
The mother is now in a quandary. If she re- 
mains on the nest to finish all the hatching, she 
will perhaps starve the first arrivals. If she 
goes off to get food for her first-born, she will * 
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