16 
ZOOLOGY OF THE VOYAGE OF THE BEAGLE. 
The plumage in the two sexes of this species differs in a manner unusual in 
the family to which it belongs. The description given in all systematic works is 
applicable, as I ascertained by dissection, only to the old females ; namely, 
back and breast black, with the feathers of the neck having a white central mark 
following the shaft, — tectrices, with a broad white band at extremity ; thighs and 
part of the belly rufous-red ; beak “ ash gray,” with cere and tarsi “ Dutch orange.” 
Male of smaller size than female: dark brown ; with tail, pointed feathers of 
shoulders and base of primaries, pale rusty brown. On the breast, that part 
of each feather which is nearly white in the female, is pale brown : bill black, 
cere white, tarsi gray. As may be inferred from this description, the female is a 
much more beautiful bird than the male, and all the tints, both of the dark and 
pale colours, are much more strongly pronounced. From this circumstance, it 
was long before I would believe that the sexes were as here described. But the 
Spaniards, who are employed in hunting wild cattle, and who (like the aboriginal 
inhabitants of every country) are excellent practical observers, constantly assured 
me that the small birds with gray legs were the males of the larger ones with 
legs and cere of an orange colour, and thighs with rufous plumage. 
The Young Male can only be distinguished from the adult bird by its beak 
not being so black, or cere so white ; and likewise in a trifling difference of 
plumage, such as in the markings of the pointed feathers about the head and 
neck, being more like those of the female than of the old cock. One specimen, 
which I obtained at the Falkland Islands, I suppose is a one-year-old female ; 
but its organs of generation were smooth : in size larger than the male ; the tail 
dark brown, with the tip of each feather pale colour, instead of being almost 
black with a white band ; under tail-coverts dark brown, instead of rufous ; 
thighs only partly rufous, and chiefly on the inner sides ; feathers on breast and 
shoulder like those of male, with part near shaft brown ; those on back of head 
with white, like those of adult females. Beak, lower mandible gray, upper 
black and gray (in the old female the whole is pale gray) ; the edge of cere and 
the soles of the feet orange, instead of the whole of the cere, tarsi, and toes being 
thus coloured. The circumstance of the young birds of, at least, one year and a 
half old, as well as of the adult males, being brown coloured, will, I believe, alone 
account for the singular fewness of the individuals with rufous thighs, a fact which 
at first much surprised me. 
The Milvago leucurus is exceedingly numerous at the Falkland Islands, and, 
as an old sealer who had long frequented these seas remarked to me, this Archi- 
pelago appears to be their metropolis. I was informed, by the same authority, 
that they are found on the Diego Ramirez Rocks, the II Defonso islands, and on 
some others, but never on the mainland of Tierra del Fuego. This statement I can 
corroborate to a certain degree, since I never saw one in the southern part of 
