1^8 Allen on Sexual Selection and the Nesting -of Hi ids. [April 



posesses intellectual powers infinitely superior to those of man ; 

 whilst the evidence that can be gathered on the subject all goes 

 to show that its intellectual powers are of precisely the same kind 

 as man's, but some of them, of course, are infinitely inferior in 

 degree, whilst others are unquestionably superior." He assumes 

 that imitation . memory, and hereditary habit, 'play the minor 

 parts.' "To credit birds." he says, "with such marvellous power 

 as blind and infallible instinct in building their nests would be to 

 place them far beyond man himself in intelligence, and allot to 

 them a faculty which is superhuman .... A bird's intellectual 

 powers advance towards maturity much more quickly than in the 

 human species. A young bird three or four days old is capable 

 of considerable powers of memory and observation, and during 

 the time that elapses in which it is in the nest it has ample 

 opportunity of gaining an insight into the architecture peculiar 

 to its species. It sees the position of the nest, it notes the mate- 

 rials, and when it requires one for itself, is it so very extraor- 

 dinary that, profiting by such experience, it builds one on the 

 same plan? Again, birds often return to the place of their birth 

 the following season, and possibly see the old home many times 

 ere they want one for themselves. This, aided by the strong hered- 

 itary impulse to build a nest similar to the one in which they were 

 born, inherited from their parents, aids them in their task." This 

 reasoning, I am free to confess, strikes me, to say the least, as 

 extraordinary ! A degree of mental power, at least of memory 

 and of imitation, is ascribed to young birds which is not only 

 •superhuman,' but of which there is neither proof, nor even 

 possibilitv of proof. Mr. Dixon has the 'three or four days old' 

 nestling taking note of and memorizing its surroundings before, 

 in the case of the higher Oscines. it //as the power to even 

 open its eves I Yet with all this ascribed precosity and keen- 

 ness of observation, and this wonderful power of memory and 

 imitation in voung birds. Mr. Dixon finds it neccessary to 

 call in the aid of "a strong hereditary impulse to build a nest 

 similiar to the one in which they were born." which is more than 

 a half-way admission of all that is implied in the modern inter- 

 pretation of instinct, or the 'blind instinct' of the non-scientific 

 writer. It we interprete instinct as -inherited habit,' what better 

 explanation do we need of the ability of young birds to build a 

 nest like that of their parents or of their species? In view of 

 the slight evidence available as to how much a nestling bird can 



