228 THE PHILOSOPHY OF BIRDS' NESTS. 



case, it is suspended from the slender twigs of the 

 weeping willow, it is made much deeper, so that when 

 swayed about violently by the wind the young may not 

 tumble out. It has been observed also, that the nests 

 built in 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 con- 

 renient 5 liole in 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 1 854, the palm swift 

 (Tachornis phsenicobea) 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 pos- 

 session 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 con- 

 siderable 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. 



