1909] The 1907 Alexander Alaska Expedition. als? 
Archibuteo lagopus sancti-johannis (Gmelin). 
American Rough-legged Hawk. 
At Coppermine Cove, Glacier Bay, July 10, a nest of the 
rough-legeed hawk was located by hearing the plaintive whistle 
of the birds. This nest was built in a sheltered niche about 
half-way up the face of a one hundred-foot limestone cliff near 
the beach. There were three half-grown young, and these were 
kept alive for some time, being fed on Microtus bodies. The 
latter were swallowed whole by the young birds. Meadow mice 
were plentiful in this locality and formed the main component 
of the diet of this hawk, as shown by the stomach-contents of the 
parents. The species was noted nowhere else but at Windfall 
Harbor, where one was seen. 
Two adults, male and female (Nos. 27, 28), and two young 
(Nos. 29, 30) were preserved from Glacier Bay, July 10 and 12. 
All are in the extreme melanistic phase of plumage, that is, sooty 
both above and below, save where the white or lighter bases of 
the feathers show through. In such specimens the feathers of 
the pectoral region are edged rather ineonspicuously with hazel, 
and in the young this color appears similarly on the head, and 
bend of the wing. It is a significant thing, as pointed out by 
Beebe (Zoologica: N. Y. Zool. Soc., 1, September, 1907, page 10) 
that the so-called ‘‘dark phase’’ of the rough-legged hawk ap- 
pears to be restricted in the breeding season to humid regions. 
“The black hawk, * * * while appearing during migration 
as isolated individuals all over the United States and southern 
Canada, seems to have a center of abundance in Ungava and 
Labrador.’’ I compared one of my birds with others in the 
U.S. National Museum from Labrador, and found them, as far 
as I could see, identical. The probability seems to be that this 
“dark phase’’ is really a geographie form occurring in regions 
of excessive humidity, and not identical with the ‘‘light phase,’’ 
American examples of which are said to not differ from the 
European form.! 
1See Chapman, Bull. Am. Mus. Nat. Hist., XX, Nov., 1904, p. 402. 
