22 



AMERICAN FORESTRY 



ture, the quills burst open at about the same time so 

 that the change from the curiously mailed creatures to 

 the light fluffy fledglings takes place in a few hours. 



The common 

 cuckoos of the 

 Old World, and 

 there are about 

 a dozen similar 

 species, ranging 

 through Europe 

 and Asia except 

 Polynesia, are 

 about ten or 

 twelve inches 

 long, brow n or 

 gray above and 

 b a r r ed below, 

 with long fan- 

 like tails and 

 pointed wings 

 giving them a 

 swift hawklike 

 flight. As a re- 

 sult, they have 

 been much per- 

 secuted by gun- 

 ners and game- 

 keepers so that 



they have become very wary and are 

 seldom seen even where their notes are 

 a familiar sound. 



The notes of the common European 

 cuckoo, so familiar to everyone be- 

 cause of the old-fashioned cuckoo 

 clocks, are always associated with the 

 coming of spring, for the cuckoos are 

 migratory, spending the winter in Af- 

 rica and returning to Europe among 

 the first of the spring birds. For this 

 reason, in spite of their bad habits, 

 they are great favorites. Thus 

 Wordsworth wrote: 



"O blithe Newcomer! I have heard, 



I hear thee and rejoice. 

 Cuckoo! Shall I call thee Bird, 



Or but a wandering voice?" 



The birds parasitized by the cuckoo 

 include most of the species smaller 

 than itself whose nests it is able to 

 discover. Apparently the egg is not 

 laid directly in the nest, for many re- 

 liable observers record having seen 



AT HOME IN A THICKET 



A black-billed cuckoo serves a spiny caterpillar to its expectant young. 

 The deep shade of the vegetation makes the photography difficult. 



the cuckoo deposit its egg on the 



ground and then carry it in its bill to the selected nest. 



The eggs of the cuckoo are small for the size of the bird, nest may contain young birds and fresh eggs at the same 



but larger than those of the host. They vary in color time. The eggs of both species are pale greenish blue 



from a dull greenish to a dull reddish gray with spots 

 and mottlings of a darker shade. Some authorities de- 

 clare that the color of the eggs is hereditary and that a 

 cuckoo always parasitizes the species 

 in whose nest it was raised and whose 

 eggs its eggs most closely resemble. 

 Other authorities disagree, however, 

 and there is as yet no proof one way 

 or the other. 



However that may be, no sentiment 

 is wasted, either by the old cuckoo or 

 by the young, for once the egg is laid, 

 the old bird never comes back to it, 

 and when it has been hatched by the 

 foster parent, the young cuckoo 

 works the rightful young or un- 

 hatched eggs on to its hollowed back 

 and heaves them overboard. The 

 parasitized birds, except for some 

 outcry at the first appearance of the 

 old cuckoo, never seem to realize the 

 calamity that has befallen their own 

 young, but take pride in filling the 

 cavernous mouth of the intruder. 



In the New World cuckoos, the 

 parasitic habit is not the rule, al- 

 though all species are rather shiftless 

 nest builders and occasionally drop 

 their eggs in 

 each other's 

 nests or very 

 rarely in the 

 nests of other 

 birds. Thus in 

 the accompany- 

 ing photograph 

 of the nest of a 

 black - billed 

 cuckoo, the 

 large egg is one 

 of the yellow- 

 billed species. 

 Another evi- 

 dence of a pos- 

 sible former 

 parasitic habit 

 among the 

 American 

 cuckoos, or a 

 leaning in that 

 direction, is that 

 the eggs are not 

 always laid at 

 regular periods, 

 one each day, as 

 is normal with 

 birds. Intervals of several days sometimes elapse and a 



AN INTIMATION OF PARASITISM 



A nest of a Black-billed cuckoo containing three eggs of this species and 

 one of the yellow-billed cuckoo. The American cuckoos are shabby nest 

 builders but are not ordinarily parasitic as are the European species. 

 However, they sometimes lay eggs in each other's nests. Tn< 

 is that of the yellow-billed species. 



lie larger egg 



