NATURAL SCIENCES OF PHILADELPHIA. 
195 
the shaft. Upper tail coverts long, extending to within half an inch of the tips 
of the central tail feathers, black, except the outer series, which are white with 
dusky markings. Central tail feathers brownish black, the rest successively 
lighter, and all with a narrow border of white. Jugulum with a very decided 
light brownish suffusion, (much as in A.maculata ,) and, together with the sides 
under the wings to some distance, with rounded obsolete spots and streaks of 
dusky. Throat and under parts generally white, immaculate. Bill, legs and 
feet black. Young in August. Dimensions and proportions as in the adult. 
Upper parts a nearly uniform light ashy brown, deeper on the rump, each 
feather with a central dark field and with a light edge. Traces of the brownish 
black of the adult on the scapulars. Breast and jugulum with the suffusion 
very light reddish brown, the streaks sparse and very indistinct. 
Length 7*25, extent 15-25, wing 4-9. Bill above, tarsus and middle toe about 
•85. 
Habitat. — North America, east of the Rocky Mountains. Not on the ’Atlantic 
coast. (?) 
The preceding diagnosis expresses the most essential characters of a Sand- 
piper, hitherto confounded with the A. Bonapartei , but nevertheless perfectly 
distinct from that or any other species recognized as an inhabitant of North 
America. Though a true Actodromas , and very closely related to the A. minu- 
tilla and maculata , a similarity in size, in changes of plumage, and, to some 
extent, in general appearance, has caused it to be referred to A. Bonapartei , 
which, however, belongs to a group subgenerically distinct. But the two differ 
very materially both in tints and in the pattern of coloration of the upper parts, 
and in the character of the upper tail coverts and the jugulum. The following 
brief schedule will express the chief distinctive features of each, and render 
further comparison unnecessary. 
A. Bairdii. — Length about 7-25 inches. Bill slender, entirely black. Feathers 
extending on the lower mandible much beyond those on the upper. Edging of 
scapulars light buff color, indented. Breast and jugulum with a decided 
brownish suffusion, the markings rounded, sparse, rather obsolete. Upper tail 
coverts much lengthened, black; central tail feathers projecting but little, the 
emargination of the tail slight. 
A. Bonapartei. — Length about 7-50 inches. Bill stout, flesh colored at base 
below. Feathers extending on the lower mandible but little if any beyond 
those on the upper. Edging of scapulars bright chestnut, scarcely indented. 
Jugulum and breast with a scarcely appreciable ashy wash, the streaks narrow, 
numerous, well defined. Upper tail coverts moderate, white ; the central tail 
feathers considerably projecting, and tail quite deeply emarginate. 
The species is a true Actodromas, and belongs subgenerically to the same 
group as A. minutilla and maculata , with both of which it is very closely related, 
and requires comparison. In size it is exactly intermediate between the two, 
exceeding the minutilla by about as much as it is itself surpassed by th£ macu- 
lata. The slender black bill is very similar to that of minutilla , and the general 
pattern of coloration almost identical. The colors, however, are everywhere 
much lighter; the edgings of the feathers of the upper parts being of a light 
reddish yellow or buff, instead of the bright chestnut red of minutilla; while 
the streaks upon the breast are fewer, less distinct and more rounded. It is 
considerably smaller than A. maculata ; there is nothing of the abrupt transition 
from the dark crown to the much lighter hind neck, so conspicuous in the 
latter; the tertials want the bright reddish edgings, and the pattern of color- 
ation of the upper parts are quite different. While the suffusion of the breast 
and jugulum is much the same, the markings are more rounded, sparse and 
indistinct. There is also a great difference in the bill, as regards size, shape 
and color. The species differs from both minutilla and maculata in one important 
respect, — the character of the changes of plumage it undergoes. The young 
of both the former are usually quite as bright, if not brighter, than the adults ; 
1861 .] 
