Pie k AO Pi tO SECOND EDITION. 
THE necessity for a second edition of my work on the Accipitres 
arose in the first place out of the many corrections called for in 
the first part of my “ Synoptical List,” owing to the fact that 
that first part was rather a compilation than an original work, 
and in the second place out of the additions and corrections to 
the whole work that followed upon a more intensive study 
of the various groups. For this second edition I have had 
the advantage of consulting Mr. W. Sclater’s MS. list of the 
Accipitres which he prepared for publication in the interval 
between my two editions, but kindly placed at my disposal 
on learning of the preparation of my second edition. From 
Mr. Sclater’s MS. list I have received some amount of help with 
the nomenclature and also with the type species of the genera. 
I owe also a great measure of thanks to Mr. Outram Bangs, 
Dr. Chapman, Dr. Richmond, Dr. Wetmore, Dr. Oberholser, 
Mr. J. H. Riley, and other American friends who assisted me 
in my work at the American museums last autumn, while the 
authorities at the Brit. Museum (Nat. Hist.) and at Tring 
have continued to give me every facility for my work. Even 
now, I am not sure that I can claim that this second edition, 
practically re-written as it is, is either complete or perfect, but, 
so far as human exertion can go, I have striven to make it so, 
and I leave it to my critics to discover its shortcomings. The 
signs (*) and (f) I have prefixed to the numbers in this edition 
denote respectively that I have skins or eggs in my own collec- 
tion. Of skins I possess now about 1000 of some 200 different 
forms, while of eggs I have 1200 of 156 different forms. All 
others, needless to say, are desiderata. 
HES Kees: 
March, 1922. 
