INTKODUCTOEY. 



XV 



1821 (" Mem. Manchester Lit. and. Phil. Soc," 1824), 

 and the second from 1811 to 1828 (" Eesearches in 

 Zoology"). 



The fact is, that very few of the observations, now so 

 nmnerously made, as to the movements of summer 

 migrants, are worth anything at all ; and if data are to 

 be collected on land of a value commensurate with those 

 now being collated on information from lighthouses, 

 &c., by the Committee appointed by the British 

 Association, it will be necessary for the observer to fulfil 

 something like the following conditions. Firstly, that he 

 should be continuously engaged out of doors ; secondly, 

 that he should be entirely familiar, not only with the 

 plumage of birds, but that he should be able to re- 

 cognize most of them when flying, and be thoroughly 

 acquainted with their song, their call and alarm- 

 notes ; thirdly, that he should have a knowledge of the 

 food requirements of each species, and be able, for 

 instance, to infer, from the plentifulness of such and 



b 



