10 A CATAlOGrE OF THE BIHDS 



I can see no character to distinguisli this species from the 

 Gryr-Falcon of the older writers, ohtaiaed in ]S"orway. After a 

 careful examination of numerous examples of both forms, I am 

 satisfied that the Iceland and the ISTorwegian bird are either 

 mere varieties, or races of the same species. 



It was by the study of the plumage of this species, and its 

 near ally the Greenland Falcon, that I determined the fact that 

 these bii'ds attain their mature dress on the first moult, and 

 never afterwards change it. My attention was first drawn to 

 this subject ia 1833, and in 1838 I read a paper to the British 

 Association announcing the fact.* This was afterwards cor- 

 roborated by an attentive examination of the changes of plumage 

 of two living examples; one in my own possession, which I 

 received in 1842, and which moulted once while I had it; the 

 other was in the gardens of the Zoological Society, London, and 

 when I first saw it in April, 1849, it was in the first or nest 

 plumage, but had got a few mature feathers. I made a sketch 

 of it at the time ; I again saw it in 1851, and agaia sketched it ; 

 it was then completely mature. f It lived till 1852, and had 

 moulted three times. It is now in my possession. In both cases 

 on the first moult the plumage had the characters of the adult. 



ISTot only do all the noble or true Falcons acquire their adult 

 plumage on the first moult, but many of the ignoble species do 

 so likewise, as the Honey Buzzard, the Goshawk, the Sparrow- 

 hawk, and the Harriers. This fact cannot be too strongly pressed 

 on the attention of ornithologists, for it leads to a correct under- 

 standing of the variations of the plumage of the Falconidse. 



It may not, perhaps, be out of place to mention, that the eggs 

 of the true Falcons can be readily distinguished from the ' ' ig- 

 noble." The eggs of the former, the true Falcons, are of a pale 

 yellow coloui' when held up to the light and looked at from the 

 interior of the shell. The eggs of the Eagles, Buzzards, Hawks, 

 etc., when examined in the same manner, are of a pale green 

 hue. 



* Ann. and Mag. Nat. Hist., Vol. II., p. 241. 



t Anil, and Majj. Nat. Hist., 2nd Ser., Vol. XIII,, p. 110. 



