COMMON CUCKOW. 77 



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it should not build a nest, incubate its eggs, and 

 rear its own young like other birds? There is 

 no apparent reason why this bird, in common 

 with others, should not perform all these several 

 offices, as it is in every respect perfectly formed 

 for collecting materials and building a nest. Nei- 

 ther its external shape nor internal structure pre- 

 vent it from incubation, nor is it by any means in- 

 capacitated from bringing food to its young. It 

 would be quite needless to enumerate the various 

 opinions of authors from Aristotle to the present 

 time respecting this subject. Those of the an- 

 cients appear to be either visionary or erroneous ; 

 and the attempts of the moderns towards its in- 

 vestigation have been generally confined w r ithin 

 very narrow limits : for they have gone but little 

 further in their researches than to examine the 

 constitution and structure of the bird ; and hav- 

 ing found it possessed of a capacious stomach, 

 protruding much beyond the sternum, concluded 

 that the pressure upon this part, in a sitting pos- 

 ture, prevented incubation. They have not con- 

 sidered that many of the birds wjiich incubate 

 have stomachs analogous to those of Cuckows. 

 The stomach of the Owl, for example, is propor- 

 tionably capacious, and is almost as thinly covered 

 with external integuments. Nor have they con- 

 sidered that the stomachs of nestlings are always 

 much distended with food ; and that this very 

 part, during the whole time of their confinement 

 to the nest, supports, in a great measure, the 

 weight of the whole body : whereas, in a sitting 



