588 Mr. J. H. Gurney's Notes on 



usually the diflFerence is but slight) from specimens of a cor- 

 responding age obtained in Iceland in the greater depth of the 

 pale cross bars (measured from their upper to their lower edge) 

 on the feathers of the median and greater wing-coverts, and also 

 on the tertialsj the scapulars, and the interscapular feathers. 

 This differencBj the only constant one Avhich I can find be- 

 tween the two races, seems to be but a slender ground for 

 erecting a distinct subspecies ; but it may nevertheless be 

 convenient to use for the Grey Falcon of Greenland the sub- 

 specific term of holboelli proposed for it by Mr. Sliarpe. 



I have seen four Falcons which, from the curious admix- 

 ture of white in their plumage, appear to me to be hybrids 

 between either H. holboelli or H. islandus and H. candicans. 

 Of these, three are apparently birds of the year ; but the 

 fourth is in very nearly fully adult plumage. This very curi- 

 ous specimen has been kindly lent to me by Col. Delm^ 

 Eadcliffe, who informs me that the skin was given to him by 

 the Maharajah Dhuleep Singh, by whom the bird was ob- 

 obtained from Iceland when in immature plumage, and in 

 whose possession it lived till it had nearly completed its first 

 moult. In this specimen the likeness to H. candicans appears 

 on some of the scapulars that are on the left side of the back, 

 on the coverts and remiges of the left wing (which latter are, 

 however, unfortunately in an imperfect state, all the prima- 

 ries being lost except the first and the basal portion of 

 another), on most feathers of the upper tail-coverts, and on 

 the external rectrices on the right side of the tail. A.11 these 

 portions of the plumage closely resemble in coloration and 

 in pattern the same parts in the more darkly marked adults 

 of H. candicans, whilst the remainder of the plumage agrees 

 with that of the greyer adults of H. holboelli ; probably, there- 

 fore, this Falcon was hatched in Greenland and captured in 

 Iceland during its migration. Col. Radclifie writes to me 

 that he was informed by the Maharajah that when this bird 

 was in its immature dress " it was rather a dark-brown speci- 

 men of a northern Falcon, and that before it moulted the 

 Greenland feathers were more conspicuous than now.^^ 



I mav add that the bill in this Falcon is of a tint interme- 



