INTRODUCTORY 25 



wrong we should be in such an assumption is proved 

 by the Chaffinch, which, with her comparatively 

 clumsy bill and short legs, also makes a nest equally 

 well woven, and even rivalling in its external appear- 

 ance the Wren's globular dwelling I Then, again, the 

 Titmice, with their short bills and well-developed legs, 

 build nests in holes in trees and walls — structures so 

 loosely made that it is impossible to remove them 

 entire. But we know the Long-tailed Tit and its 

 several allies with similar tools (indeed, the bill is pro- 

 portionately shorter than in other Titmice) build nests 

 in the branches the paragon of beauty and well-woven 

 perfection. The Penduline Titmice and the Dipper 

 may be quoted as very similar instances. The Swift, 

 with its weak bill and abnormally short legs, seems 

 totally unable to make an elaborate nest ; but we know 

 that it seeks a hole for its purpose from other motives 

 than its seeming inability to make one, and, as is the 

 case with almost all hole-building species, irrespec- 

 tive of their natural tools or physical peculiarities, it 

 is poorly made. Some of the Swifts, however, make 

 more elaborate and remarkable nests, as we shall find 

 in a future chapter (conf. p. 104). Against the Swifts 

 we have the case of the Humming-birds, which, with 

 their almost functionless legs, build some of the most 

 beautiful cradles in all the wide and varied range of 

 avine life. Then, again, the Swallows and the House- 

 Martins possess similar tools to those of the Swifts, 

 yet they build well-made structures either fastened to 



