SCAUP DUCK. 
227 
at no great distance from the sea. Is most numerous 
in the waters of the Chesapeake ; and, with the con- 
noisseurs in good eating, ranks next in excellence to 
the canvass-back. Its usual weight is about a pound 
and three quarters avoirdupois. 
The red-head leaves the bay and its tributary streams 
in March, and is not seen until late in October. 
The male of this species has a large flat bony labyrinth 
on the bottom of the windpipe, very much like that of 
the canvass-back, but smaller ; over one of its concave 
sides is spread an exceeding thin transparent skin, or 
membrane. The intestines are qf great width, and 
measure six feet in length. 
277 . ANAS MARI LA, LINNAEUS AND WILSON. SCAUP DUCK. 
WILSON, PLATE LXIX. FIG. III. — EDINBURGH COLLEGE MUSEUM. 
This duck is better known among us by the name 
of the blue bill. It is an excellent diver, and, according 
to Willoughby, feeds on a certain small kind of shell 
fish called scaup, whence it has derived its name. It is 
common both to our fresh water rivers and sea shores 
in winter. Those that frequent the latter are generally 
much the fattest, on account of the greater abundance 
of food along the coast. It is sometimes abundant in 
the Delaware, particularly in those places where small 
snails, its favourite shell fish, abound ; feeding also, like 
most of its tribe, by moonlight. They generally leave 
us in April, though I have met with individuals of this 
species so late as the middle of May, among the salt 
marshes of New Jersey. Their flesh is not of the most 
delicate kind, yet some persons esteem it. That of 
the young birds is generally the tenderest and most 
palatable. 
The length of the blue bill is nineteen inches, extent 
twenty-nine inches ; hill, broad, generally of a light blue, 
sometimes of a dusky lead colour ; irides, reddish ; 
head, tumid, covered with plumage of a dark glossy 
green, extending half way down the neck ; rest of the 
