389 



outward circumstances, but due to a modification of instinct in the 

 course of several generations. 



With regard to the material used by birds in building, it seems 

 to depend very much upon what comes to hand. Some keep more 

 to the same materials than others ; biit that they will often abandon 

 the old material for a new and a better one if thrown in their way, 

 is shown by a circumstance mentioned by the late Mr. W. Thompson, 

 of Belfast, that " the chaflBinches and sparrows at Whitehouse, near 

 that city, which build around two cotton-mills, always use cotton in 

 the construction of their nests." * Wallace also has remarked that 

 " thread and worsted are now used in many nests instead of wool 

 and horse-hair." t 



A curious case occurred at Cambridge many years ago when the 

 Botanic Garden was in the midst of the town. The jackdaws 

 that frequented the buildings about there were very much in the 

 habit of stealing the wooden labels attached *to the plants, and 

 carrying them off when the gardeners were not on the watch for 

 constructing their nests. These labels on being searched for were 

 found in large numbers in holes in the steeples and towers of the 

 churches and colleges near, as well as in the chimneys of houses. 

 From one chimney shaft in the immediate neighbourhood of the 

 garden which was found " stopped up below," no less than eighteen 

 dozen labels were got out and brought back to the curator. % 



As the song of caged birds often difiers from that of the same 

 species when at liberty, so too it would seem to be with the nests. 

 On this point Wallace remarks that " birds brought up from the 

 egg in cages do not make the characteristic nest of their species, 

 even though the proper materials are supplied them, and often 

 make no nest at all, but rudely heap together a quantity of 

 materials." § He also quotes Wilson as " strongly insisting on the 

 variety in the nests of birds of the same species, some being so 

 much better finished than others, and he believes that the lens 

 perfect nests are built by the younger, the more pex-fect by the 

 older birds." |1 



♦ See Ann, and Mag. of Nat. Hist., vol. viii., p. 412. t "Wallace, 



p. 227. t See Loud. Mag. Nat. Hist., vol. vi., pp. 397-8. § Wall., 



pp. 219, 20. II Id., p. 224. See also an Article by Wallace, on the 



"Philosophy of Bird's Nests." Intellectual Observer, vol. xi., p. 413. 

 B 



