PREFACE. 



AT is now nearly twenty years since the last Volume, or Second 

 Supplement to the Synopsis of Birds, was published; and it is satis- 

 fectory to observe liie daily increase of the admirers of Natural 

 History in general, particularly in the department of Ornithology. 



At the time of publishing the Synopsis, we had no intention 

 of writing further on the subject ; but we have subsequently availed 

 ourselves of every opportunity of correcting and amending any errors 

 or misrepresentations which had unavoidably arisen in that work, 

 and were tempted, at the same time, to commit to paper, descriptions 

 of every new discovery in that branch ; and especially to compare 

 Birds, nearly similar in plumage, with each other, with the intention of 

 ascertaining whether they were distinct as to species, or varying only 

 in sex, or immature in feather. In this we trust we have succeeded 

 in very many instances, and have to acknowledge the great assistance 

 afforded by the labours of M. Temminck, of Amsterdam, whose 

 views have been directed to the same point, as may be seen more 

 fully in his last Manuel dOrnitJwlogie. 



