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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