10 NORTH AMERICAN DUCKS, GEESE, AM> SWANS. 
a-> we now available respecting the distribution and migration of the 
ducks, geese, brant, and swans of North America, together with a 
brief reference to a few species which occur in Panama and the West 
Indie-. A summary is also giyen of existing information as to the 
breeding grounds occupied by the several species, their winter resorts, 
the routes selected in passing north and south, and the times of mak- 
ing their journeys. Other subjects of investigation still underway 
are the food habits of the various species, principal ducking grounds, 
methods of hunting, and the means which have thus far proved most 
successful in the protection of these birds. 
The problem of the legal protection of ducks, geese, and swans has 
two phases — protection during the breeding season and protection 
during migration and in winter. The first phase concerns 1^4 species 
of ducks breeding in the United States, while 4»'» species come under 
the head of winter residents of the United States. It happens, 
however, that from the economic point of view the 24 species of ducks 
and geese that breed in the United States comprise the most important 
North American species; among this number also are all the species 
that at the present time need protection while breeding. Of the 24 
species, 5 are numerically unimportant and are confined to the south- 
ern portions of the United States and southward, so that the}' are of 
little importance for the market and as objects of sport. These 5 are 
the Florida duck, mottled duck, masked duck, black-bellied tree-duck, 
and fulvous tree-duck. 
The other 19 species that breed regularly and commonly in the 
United States are as follows: 
Shoveler, Spatula clypeata. 
Pintail, DaJUa acuta. 
Wood duck. Aix sponsa. 
Redhead, Aythpa americana. 
Canvasback, Aythya vallisneria. 
Lesser scaup, Aythya affirm. 
Ring-necked duck, Aythya collaris. 
Ruddy duck, Erismaiura jamaia nsis. 
Canada goose, Branta canadensis. 
White-cheeked goose, Branta canadensis 
ocddentalis. 
American merganser, Merganser ameri- 
canus. 
Hooded merganser, Lophodptes cucul- 
latus. 
Mallard, Anas boschas. 
Black duck, Anas obscura. 
i Sadwall, Chaulelasmus streperus. 
I laid pale, Mareca mnericana. 
( \ recn- winged teal, Nettion carolinense. 
Blue-winged teal, Querquedula discors. 
Cinnamon teal, Querquedula cyanoptera. 
A glance shows that this list comprises the species that in later 
years have decreased most iii numbers, and hence that most need 
protection. 
CAUSES OF DECREASE IN NUMBERS OF WATERFOWL, 
The principal causes of the diminished numbers of waterfowl have 
been market hunting, spring shooting, and the destruction of the 
breeding grounds for fanning purposes. Previous to twenty years 
ago, market hunting was the principal factor in the steady diminu- 
