BLACK-FOOTED MOLLYMAWK. 
on the north, east and south sides, but is not found, except rarely, on the west 
side. It is lik ewise common on the sedge-covered slope near the beach, in the 
same habitat with Sula cyanops. On one or two occasions I noted them in 
the interior with D. immutabilis.’’ 
“ Tim nest is a mere hollow scratched in the bare sand, without even a 
rim of sand raised around it. 
“ Eggs. —Doctor Richards (1909) describes the eggs as follows : ‘ Each 
pair of birds—and this applies to both species — -rarely lays more than one egg 
in a season, if undisturbed; and if a second egg should be deposited the first 
is thrown out, leaving but one to incubate. If, as was formerly the case, the 
nests are systematically robbed, four eggs are usually supplied by each. In 
nearly all published descriptions of eggs of the Diomedeidce they are referred 
to in terms somewhat as follows : “ White, sometimes speckled or sprinkled 
on larger end with reddish-brown ” (Ridgway), giving the impression that 
they resembled, on a large scale, eggs of the Stormy Petrel, for example. 
While this may be true of some species, it would be inappropriate for a great 
many specimens of D. nigripes, though some are faintly speckled or even 
immaculate. In many instances, however, these eggs are boldly and handsomely 
splashed with dark brownish-red, in some forming a cap or wreath about one 
end, usually the larger; in others, extending over nearly one-half the shell; 
in fact, there is as much color, relatively, as on an average egg of any of our 
larger Buteos, though it is apt to be more constantly confined to one end. 
Compared with eggs of immutabilis they average more colour, but extremes 
easily overlap and identity cannot be determined from the eggs alone.’ 
“ The measurements of 45 eggs, in various collections, average 108"8 by 
70‘3 millimetres ; the eggs showing the four extremes measure 120‘7 by 69‘5, 
109-5 by 86, 98-1 by 68-4 and 109*3 by 56 millimetres (98-1 to 120-7 by 56 
to 86). 
“ Young. —-Doctor Richards (1909) says further : ‘ Incubation lasts about 
six weeks, both birds taking turns on the nest, so that the egg is constantly 
covered. The young are fed, in the well-known manner, by regurgitation 
from the throat of the parent, remaining about the islands until the following 
June or July, so that the entire reproductive period occupies about one-half 
the year.’ 
“ The young are probably nearly six months’ old before they are able to 
fly. 
“ Plumages. —-Immature birds, during the first year at least or perhaps 
longer, are in uniformly dark sooty plumage, a faint suggestion of the white 
face at the base of the bill and a few white feathers on the upper tail-coverts 
probably indicate approaching maturity. The dull white face and the pure 
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