42 BIRDS OF OHIO. 
Its migrations cover the period from the second week in 
March to the second week in April, and at the same period 
in October and November, except that it may tarry even into 
December in favorable years. 
38. (147.) AyTHYA VALLISNERIA (Wils.). 259. 
Canvas-back. 
Synonyms: A*ithya vallisneria, Fuligula vallisneria, Anas val- 
lisneria. 
Canvas-back Duck. 
Kirtland, Ohio, Geol. Surv., 1838, 166, 187. 
The delight of the epicure, and therefore hunted down by 
every market hunter, this duck has become scarce. I have 
seen it twice in Lorain county in the last ten years, once 
when it visited the Oberlin water-works reservoir. 
It appears to migrate at the same time as the Redhead, 
but migration dates are too few to make any positive state- 
ments possible. 
39. (148.) AyTHYA MARILA Linn. 256. 
Greater Scaup Duck. 
Synonyms: Fulix marila, Fuligula marila, Aythya marila ne- 
arctica. 
Greater Black-head, Big Black-head, Blue-bill, Broad-bill, 
Raft-duck, Flocking Fowl, Shuffler, American Scaup Duck. 
Kirtland, Ohio Geol. Surv., 1838, 166, 187. 
In my experience this Scaup Duck is about one-fourth as 
numerous as the Lesser Scaup; that would make it hardly 
common. There is often one or two of this species in the 
flocks of Lesser Scaups which visit the Oberlin water- 
works reservoir every year. There is no evidence that this 
species breeds within the state. The birds which may be 
found on the reservoirs during the summer, while they may 
be of both sexes, are not breeding, but are no doubt wound- 
ed birds unable to migrate. Their bodily condition would 
make breeding out of the question. 
The migrations are rather late, occurring late in March or 
early in April, and continuing for two or three weeks. In 
