INTRODUCTORY 



so forth (amongst which we may allude to those 

 of the present writer, with criticisms thereon by 

 Allen, the American ornithologist) relating to nests, 

 scattered over various books and periodicals of a 

 natural history character; whilst the nests of a 

 very large proportion of the twelve thousand (in 

 round numbers) species of known birds have been 

 described in numerous ornithological works. Nests, 

 however, have never yet received that special treat- 

 ment which we intend to devote to them in the 

 present little volume. 



The arrangement of the subject matter, so that 

 it may be at once comprehensive and intelligible, 

 in a work of this character, is attended by no little 

 difficulty. Nests do not admit of the same methods 

 of classification as the birds that build them. The 

 various types of nests are by no means peculiar 

 to groups or even genera, because we find most 

 wonderful exceptions in what are obviously closely 

 allied species. Neither can we classify nests by 

 materials, for we are confronted by a still more 

 bewildering similarity on the one hand, or an equal 

 diversity on the other — remotely related species 

 employing the same fabrics, closely allied birds, 

 even the same species, selecting vastly different 

 ones. It seems, therefore, the most satisfactory 

 way to divide nests into various grades and types 

 quite irrespective of their ownership, and as far as 

 possible to deal with the crudest nest forms first. 



