174 
DUSKY DUCK. 
DUSKY DUCK — ANAS OBSCURA Plate LXXII. Fig. 5. 
Arct. Zool. No. 469. — Lath Syn. ili. p. 545. — Peole’s Museum^ No. 2880. 
BOSCHASf Jardine.* 
Anas obscura, JBonap. Synop. p. 384. 
This species is generally known along the sea-coast of New 
Jersey, and the neighbouring country, by the name of the black 
* Having now ari’ived at the conclusion of a gi’oup which holds a very pro- 
minent rank in the ornithology of Northern America, a few general observations 
regarding their economy, with an enumeration of those species omitted by Wil- 
son which have been since discovered, may not be deemed improper. 
The Anatidce^ or those birds generally known under the denominations of 
ducks, geese, and swans, taken as a family, will range with groups of great ex- 
tent and varied form, as the falcons, the parrots, or pigeons, and will present 
similar modifications. The characters of the greater part of the groups which 
inhabit the northern and temperate regions of the world, have been already 
drawn by Dr Leach and Dr Fleming, and one sub-family has been more lately 
analyzed by Mr Swainson, as far as our knowledge of them extends, apparently 
with tolerable accuracy. They, however, want comparison with the tropical forms, 
which depart so much in their manners from those we are accustomed to see, 
and by which our opinions have hitherto been led. The wood ducks, constitu- 
ting Mr Swainson’s genus Dendronessa — the long-legged whistling ducks of India 
— those birds allied to the little Gambia goose, and those approaching in their 
form to the Grallatores, all want our close examination. 
In distribution, the Anatidce extend over the world, from the warmest tropics 
to the extreme arctic cold, but exist in greatest abundance near the confines of 
temperate regions, and in northern latitudes. Their habits may be called truly 
aquatic, as the presence of water is necessary, even in the most aberrant forms, 
for their healthy support. Some groups are exclusively aquatic, and never quit 
the sea or large inland lakes, except during the season when the duties of incu- 
bation for a while call them to the shore. These may be termed pelagic or sea 
ducks, and feed on fish and raoluscse ; others delight in lakes and rivers as well 
as the sea, resort more frequently to the land, seek the same nourishment, and 
both are expert divers. Some hold a middle way, are as much on land as on 
water, and, in addition to the food of the truly sea species, live on the spawn of 
fresh-water fish, insects peculiar to muddy banks and slimy pools, with vegeta- 
bles, such as the tender shoots of the grasses or newly-sown grains, or, while on 
