Birds. 9413 



there of the most insectivorous and least granivorous of all the 

 finches. 



But it may be replied that the Javan grosbeak feeds entirely on 

 seeds, and yet its geographical distribution does not extend to tem- 

 perate regions. This is true ; but as its food is mainly confined to 

 the very driest kinds, such as rice and millet, and as it is not found to 

 eat any green food, it can only exist in very hot countries, like India, 

 where the supply of seeds of this character is perennial. 



Why, then, is it that the Passer moutauus of Java is also tolerably 

 common in England ? The reply is that it is nearly omnivorous ; it 

 will eat most kinds of seeds whether oleaginous or farinaceous, many 

 vegetables, insects, and even flesh ; and, also, it passes the night in 

 holes in trees, well lined with hay and feathers, which it conveys there 

 during the winter months for the purpose of warmth. 



To test the effect of cold upon birds which naturally are not found 

 beyond the tropics, the following experiment was made at Blackheath. 



In the angle of a house an aviary was constructed, having the top 

 and one side of glass, the front being secured by open wire-work : old 

 materials were used in its construction, and no part fitted very accu- 

 rately, so that there were many draughts : during the most inclement 

 weather a piece of American imitation leather was hung in front to 

 keep out the wet, but, as this was flapped by every gust of wind, it 

 kept out but little cold air. 



The aspect of the open side was nearly south-west, but, as the rays 

 of the sun were much intercepted by trees, the situation could scarcely 

 be considered favourable for warmth. 



The experiment was commenced in the autumn of 1863, and was 

 continued through the winter of 1863 — 4, which was very severe. 



It was with difficully that, on many days, water could be kept 

 liquid suflSciently long to enable the birds to drink ; this was gene- 

 rally effected by placing the fountain on a hot tile during the day, 

 and removing it at night. 



The birds experimented on were the Javan grosbeak [Padda oryzi- 

 vora), before adverted to — two specimens, male and female; the 

 rufous-necked weaver-bird {Hyphantornis textor), from Western 

 Africa — two specimens, both males ; the red-beaked weaver-bird {Eu- 

 •plecies sanguinirostris), also from Western Africa — male and female ; 

 and the blue-bird [Spiza cyanea), from the warmer parts of North 

 America. In addition the aviary contained nearly all the British 

 finches, including the Passer montanus before adverted to. 



The success was complete : none of the foreign birds showed any 



