2818 The Zoologist— November, 1871. 



therefore, belongs the credit of first discovering and making public the 

 exact state of the case. It is to be observed that nearly all the true falcons, 

 as can be proved by keeping them in captivity, assume the plumage of 

 maturity at their first moult, which usually takes place when the birds are 

 from nine to fifteen months old ; and, moreover, that the feathers of the 

 young are generally characterized by longitudinal markings, while those of 

 the adult have most of the markings disposed transversely. After this one 

 change there is no good reason for supposing that the colours of the 

 plumage materially alter at any succeeding moult. The feathers become 

 faded or bleached with time, but they are thrown off every year, and fresh 

 ones take their place, the same in colour and markings as those originally 

 assumed by the bird at its first moult. This has been observed in several 

 instances to be the case with the Greenland falcon. The adult so beautifully 

 figured by Mr. Wolf in the ' Zoological Sketches ' (plate 34), when brought 

 to the Zoological Gardens was said to have been taken in Greenland the 

 same year. Its plumage then had the longitudinal markings of immaturity, 

 which at the first moult changed into the transvei-se ones represented in the 

 plate, and though the bird hved for several yeai-s afterwards, and regularly 

 underwent its annual moult, Mr. Wolf, who watched it carefully, and from 

 time to time sketched it, was convinced that no further alteration in colour 

 took place. Prior to Mr. Hancock's discovery of this fact, it had been 

 thought by him and others that the young of the Greenland falcon was of a 

 dark colour, and resembled the young of the Iceland falcon, next to be 

 described, and aU the white falcons, whether marked longitudinally or 

 trans vei-sely, were believed to be adult. But this error being con-ected, p,nd 

 the mode of determining the young as well as the old of each form being 

 established, it was not difficult to point out the characters which dis- 

 tinguish the two at any age. The most apparent of these may be briefly 

 stated to lie in the bills and claws of the Greenland bird being in Hfe of a 

 very pale hue, while in the Icelander the same parts are more or less of a 

 dusky horn-colour; and, as regards the plumage, the white in the Green- 

 land falcon being, as it were, the grouhd colour of each feather on which the 

 dark marking, if one exist, is displayed, the ground in the other form being 

 dark, with a liglit marking thereon. In other words, in the Greenland 

 bird, at all ages, the prevailing colour is white, while in the Icelander it is 

 dark, being brown or gray according as the example is young or old. The 

 Greenland falcon seems to be most plentiful in the inhospitable regions 

 which enclose Baffin's Bay and extend to the westward. From this tract 

 adult birds seldom wander to other lands, though the young, especially in 

 autumn and winter, occur regularly in Iceland, and not unfrequently in the 

 Dominion of Canada, from Newfoundland (where, according to Mr. Reeks, 

 it is a pretty regular visitant in the fall) westward, the United States, the 

 British Islands, and even in countries still more remote from the place 



