io8 Instinct, 



work of Intelligence, we may be ready to grant to 

 some of them a good measure of Intelligence. 

 What we wish now especially to controvert, is the 

 doctrine that all Instinct is the result of observa- 

 tion, either of the present races or of past races, 

 from which the fixed habits have been transmitted, 

 or that high wisdom and skill manifested in an act, 

 are any certain proof of comprehension on the part 

 of the actor. 



One of the most conclusive arguments against 

 this doctrine, that birds build nests by observa- 

 tion or the study of the nest in which they were 

 hatched, is found in the habits of the Cow-bird {Mo- 

 lothrus pecoris) already referred to. This bird nev- 

 er builds a nest at all. The young Cow-birds wake 

 to life in all sorts of nests where their mothers de- 

 posit their eggs, — in Ground-sparrows' and Tree- 

 sparrows' nests — in Warblers' and Vireos' nests. 

 Now according to the observation theory, we ought 

 to find these birds building nests; and such nests 

 as each one was raised in. But we find Instinct as- 

 serting its sway. In the spring time we see hun- 

 dreds of these birds in New England congregating 

 together — not with the birds in whose nests they 

 were hatched. We find them with a note of their 

 own and in spite of their opportunity of observa- 

 tion and in spite of the care of their foster-parents, 

 we see these perverse birds refusing to build nests 

 of any kind, but putting out their own young to be 

 cared for by other birds, just as their own parents 

 did. They follow the habits of their parents, 



