PRESACE TO FIRST EDITION. 
In concluding my work on the Accipitres, a work which I fear 
has grown far beyond my original intention of publishing a 
mere list, I have to acknowledge my indebtedness to the sources 
from which I have received inspiration and help. In the first 
place I must acknowledge that a good deal of the systematic 
part and the generic characters have been borrowed from 
the late Richard Bowdler Sharpe’s “‘Catalogue of the Accipitres 
in the Collection of the British Museum”’ (1874) of which 
his annotated copy, laid down on sheets and extended, came 
into my possession after his death, as also his interleaved 
copy of the Accipitves portion in Gray’s “‘ Genera of Birds,” 
upon which he based his 1874 monograph. For permission to 
make use of the former work I have to thank the Trustees of 
the British Museum. I have also derived assistance from 
Mr. W. L. Sclater’s work at the British Museum (Natural 
History) in so far as his had preceded mine, and his MS. 
Catalogue of the skins, which he kindly gave me permission 
to use. I have also to thank Mr. Bannerman, Mr. Chubb and 
other assistants at the Museum for help rendered during my 
studies there. To Lord Rothschild and Dr. Hartert for the 
use of the superb collections at Tring I am grateful, and to 
Dr. Hartert especially for much personal assistance. The 
Rev. F. C. R. Jourdain and a number of other friends have also 
given me help and encouragement in various ways in what, 
although an arduous and unprofitable undertaking, will I 
hope be of some permanent help in systematizing this interesting 
group of birds. 
March, 1920. 
