INTRODUCTION. 



THE present volume is the first of the series of the new edition 

 of the ' Avifauna of British India,' and, funds permitting, it is 

 proposed to bring out about one volume every two years until 

 the work is completed. 



It has been my endeavour in writing this volume to disturb as 

 little as possible the classification adopted by Gates in the first 

 edition but during the thirty-two years that have elapsed since 

 his first volume was published, much scientific work has been done 

 and many discoveries made which have rendered alterations 

 imperative ; some of these, unfortunately, are of a drastic nature. 



In the first place, the trinomial system has been adopted a de- 

 rision which has added very greatly to the number of birds to be 

 described, i.e. to the total number of species and subspecies, 

 though, on the other hand, it has reduced the number of species, 

 for it has relegated to their proper positions as subspecies or 

 geographical races many forms which have hitherto improperly 

 held the status of species. 



In using the trinomial system I have adhered to the follow- 

 ing rules : 



Forms, or groups of forms, have been named as specific when 

 there are no forms known which directly connect them with other 

 forms or groups of forms. 



Subspecies or geographical forms have been recognized when 

 they differ in degree either in size, colour or some other 

 characteristic from the forms with which they are most closely 

 connected, yet, though linked with these forms by others which 

 are intermediate, are themselves constant within some given area. 



YOL. I. B 



