Mr. R. B. Sharpe's Catalogue of Accipitres. 585 



he recently favoured me, that I think it may be useful to 

 quote his own words on the subject. He writes thus : — " My 

 own view (originally expressed in the Hist. N. Am. Birds) 

 is that the arctic American (continental) bird is a race in- 

 termediate between H. islandus and H. gyrfalco, the lighter- 

 coloured specimens approaching (in fact I do not see how 

 they can be distinguished from) H. islandus, while the darker 

 ones appear to me to be undistinguishable from H. gtjr- 

 falco ; the majority of specimens, however, are about halfway 

 between.^' 



In a subsequent communication, dated in July of the 

 present year, Mr. Eidgway remarks, " With some additional 

 material, I see no reason to change the views already ex- 

 pressed.^^ 



In Mr. Sharpe's volume the same view is taken of these 

 Falcons as is held by Mr. Dresser, the range of H. gyrfalco 

 being there stated as extending from Northern Europe 

 '^ across Northern Asia and North America''"^. Tome it 

 seems a not unreasonable supposition that both H. gyrfalco 

 and H. islandus may be found in arctic America ; but I have 

 not sufficient data to enable me to offer an opinion as to the 

 specimens of an intermediate character alluded to by Mr. 

 Ridgway. 



Professor Newton, in his edition of Yarrell's * British 

 Birds,' vol. i. p. 47, gives some interesting particulars as to 

 the differences existing between H. gyrfalco and H. islandus f 

 in the measurements and proportional dimensions of the 

 sternum and coracoid bones ; and it is much to be desired 

 that a corresponding examination and comparison of these 

 bones could be made as regards the arctic Falcons of North 

 America. 



It is unfortunate that no adult specimen of a grey North- 

 American Falcon from the countries west of Greenland and 

 Labrador exists, so far as I am aware, in any British collec- 

 tion ; and specimens that are not adult are not of very much 



* Vide Sharpe's Cat. vol. i, p. 417. 



t Professor Newton informs me that the sterna of F. islandus referred 

 to in his work were all taken from Icelandic specimens. 



