of Naumann's ' Vogel Deutsclilands.' 47 



difficult. In the first place, the bills and claws of the Greenland 

 bird seem to be in life always white, or nearly so, while in the 

 Icelander the same parts are more or less dusky horn-colour. It 

 occasionally happens however that, on a cursory inspection of dried 

 specimens of the Greenland race, these organs present a some- 

 what dark appearance, but this will be found on closer inspection 

 to be merely the effect of extravasated blood. Another charac- 

 ter is, that though there is very considerable variation between 

 individual birds of either form, it will always be found that in 

 the Greenland Falcon, the white is as it were the ground-colour 

 of each feather on which the dark marking is displayed, whereas 

 in the Icelander the ground is dark with a light marking thereon. 

 In other words, in the Greenland bird at all ages the prevailing 

 hue is white, while in the Icelander it is dark — being brown or 

 grey, according as the specimen is young or old. 



The variation between individuals, to which we have just 

 alluded, has no doubt been the primary cause of the confusion 

 which has existed on the subject of these birds. But Mr. Han- 

 cock has shown that to distinguish between them is always a 

 matter of simple observation ; and it may be added that, in 

 practice, it is believed the separation will be found more easy 

 than would appear. The differences are indeed often very great, 

 for out of some twenty or thirty examples, perhaps not more 

 than three or four may be found exactly alike ; but the extent of 

 this variation is by no means unlimited ; and we believe that Mr. 

 Hancock, and some other naturalists who partake of his opinions, 

 declare that they can unfailingly determine between the two 

 birds. They say that a Greenland Falcon of the darkest com- 

 plexion is yet whiter than the lightest Icelander; and even in the 

 absence of a series of specimens for comparison, it is asserted 

 that the colour of the bill will be always a sufficient test *. 



* As if still further to complicate the matter, examples of the Iceland 

 Falcon are occasionally found showing a tendency to albinism, having 

 perhaps two or three feathers on one side nearly pure white, while the cor- 

 responding ones on the other side are the same as the rest of the body. 

 But at other times the pied markings are more regularly disposed, and we 

 believe it was a specimen of this description which led Mr. Hancock into 

 the error, afterwards corrected in his second paper, as before mentioned. 



