420 The Philosophy of Birds' Nests. 



the warm Southern states are much slighter and more porous 

 in texture than those in the colder regions of the north. Our 

 own house- sparrow equally well adapts himself to circumstances. 

 When he builds in trees, as he, no doubt, always did originally, 

 he constructs a well-made domed nest, perfectly fitted to protect 

 his young ones ; but when he can find a convenient hole irf a 

 building or among thatch, or in any well- sheltered place, he 

 takes much less trouble, and forms a very loosely-built nest. 



A curious example of a recent change of habits has occurred 

 in Jamaica. Previous to 1854, the palm swift (Tachornis 

 phcenicobea) inhabited exclusively the palm trees in a few 

 districts in the island. A colony then established themselves 

 in two cocoa nut palms in Spanish Town, and remained there 

 till 1857, when one tree was blown down, and the other stripped 

 of its foliage. Instead of now seeking out other palm trees, 

 the swifts drove out the swallows who built in the Piazza of the 

 House of Assembly, and took possession of it, building their 

 nests on the tops of the end walls and at the angles formed by 

 the beams and joists, a place which they continue to occupy in 

 considerable numbers. It is remarked that here they form 

 their nest with much less elaboration than when built in the 

 palms, probably from being less exposed. 



A fair consideration of all these facts will, I think, fully 

 support the statement with which I commenced this article, 

 and show that the mental faculties exhibited by birds in the 

 construction of their nests are the same in kind as those mani- 

 fested by mankind in the formation of their dwellings. These 

 are, essentially, imitation, and a slow and partial adaptation to 

 new conditions. To compare the work of birds with the highest 

 manifestations of human art and science is totally beside the 

 question. I do not maintain that birds are gifted with reason- 

 ing faculties at all approaching in variety and extent to those 

 of man. I simply hold that the phenomena presented by their 

 mode of building their nests, when fairlv compared with those 

 exhibited by the great mass of mankind in building their 

 houses, indicate no essential difference in the kind or nature of 

 the mental faculties employed. If instinct means anything, it 

 means the capacity to perform some complex act without 

 teaching or experience. It implies innate ideas of a very 

 definite kind, and, if established, would overthrow Mr. Mill's 

 sensationalism and all the modern philosophy of experience. 

 That the existence of true instinct may be established in other 

 ways is not improbable, but in the particular case of birds' 

 nests, which is usually considered one of its strongholds, I 

 cannot find a particle of evidence to show the existence of any- 

 thing beyond those lower reasoning powers which animals are 

 universally admitted to possess. 



