Vol. XVII"] 
1900 J 
General Notes. 
387 
Description of the Nestling Plumage of Falco islandus. — While pre- 
paring a report on the various collections of birds received by the Ameri- 
can Museum of Natural History through the Peary Expeditions to Green- 
land, I learned from Mr. J. D. Figgins, taxidermist of the expeditions of 
1896-97, that Mr. R. D. Perry, one of the members of the expedition of 
1897, secured two specimens of Falco islandus from the nest. The plum- 
age of' the species at that age having a very important bearing on the ques- 
tion of the relationships of the Greenland Gyrfalcons, I wrote Mr. 
Perry with the result that he kindly forwarded the birds for examination, 
and with his permission, I append the following description, which applies 
equally to both specimens: 
Crown and nape as in the adult, white with narrow blackish shaft-streaks 
increasing in width posteriorly; back white, the apical half of the feather 
with a guttate or elliptical ovate fuscous mark bordered by white, and 
sometimes continuing as a narrow line down the shaft of its feather to 
the base ; rump white with narrow fuscous shaft-streaks ; quills with bro- 
ken blackish bars and a sub-apical blackish tip, agreeing in pattern with 
the quills of the adult bird, but with the white portions, especially of the 
outer web, slightly suffused with pale ochraceous; wing-coverts as in the 
adult but with the blackish markings linear rather than transverse; tail, 
about two thirds grown, pure white without bars or other markings; 
under parts white, as in the adult, with a few fuscous shaft-streaks; under 
tail-coverts white, unmarked. 
In general appearance these birds are quite as white as fully adult 
individuals and apparently prove that Falco islandus is, as has been 
claimed, white at all ages, and they thus furnish confirmatory evidence of 
its specific distinctness. 
Moulting specimens of Falco rusticolus show that the immature, linear- 
marked plumage is directly succeeded by the mature barred plumage and 
it is probable, therefore, that the adult plumage of F. islandus is acquired 
in the same manner. — Frank M. Chapman, American Museum Natural 
History , New Fork City. Auk, XVII, Oct., 1900, p * 3 8 ^ , 
