BLACK DUCK 
79 
barnacles, sand-fleas, water-fleas, sow-bugs, shrimps, crayfishes and crabs. As many 
as thirty small crabs have been found in one stomach. The other animal food con- 
sists of insects, aquatic beetles and bugs, dragonflies, especially in their immature 
stages, crickets, grasshoppers, caddisflies and their larvse, winged flies, and ants. 
Fishes and their eggs are rare, and a few marine worms have been found. 
The vegetable food (75.91%) is very like that of the Mallard, but not so varied. 
Three-fourths is derived from pond-weeds, eel-grass and wild celery. Leaves, stems, 
tubers, winter buds and seeds of pond-weeds are eaten. No fewer than 4000 seeds of 
eel-grass were taken from the gizzard and gullet of one Black Duck. The grasses 
and sedges compose 11% of the diet, and of less importance are the smart-weeds, 
burr-reeds {Sparganium) , water-lilies, coontail, wapatos, pickerel-weed, huckle- 
berries, etc. 
A few stomachs of downy young show that these consume from 40 to 79.25% of 
animal food, much more than adults, and this includes eggs of small fishes, caddis 
larvse, etc. The vegetable food of the young showed no especial peculiarities. 
The crops of two birds shot in winter in Maine contained the red berries of Le- 
pargarea canadensis, a northern shrub not known in Maine (O. W. Knight, 1908). 
Eleven which I shot at Ipswich in September w'ere crammed full of the two small 
species of snails, Melampus lineatus and Litorina rudis, and had nothing else. 
Audubon gives a long list of the diet: newts, young frogs and toads, tadpoles, all 
sorts of insects, acorns, beechnuts, grain, small quadrupeds, earthworms, leeches, 
and shell-fish, — a very complete accoimt. 
In the Magdalens in summer they are said to eat blueberries high up in the hills 
in company with the Hudsonian Ciu'lew (Sanford, Bishop and Van Dyke, 1903), and 
O. W. Knight (1908) recorded similar habits in Maine. I found them feeding on 
blueberries on Martha’s Vineyard Island from mid-August to mid-September, and 
they must have taken them at night; for these particular birds were gathered around 
the edge of a pond all day, their excrement showing absolutely purple in color. Later, 
on November 22, I collected stomachs from the same group of ducks. These were 
analyzed by the staff of the U.S. Biological Survey, and found to contain very 
diverse material, ranging from 100% to 0% vegetable, and from 80% to 0% animal 
matter. One stomach contained three fishes (Fundulus), 35%; remains of fishes, 
40%; 650 seeds of Scirpus sp? (rush), 8%; 31 seeds of Scirpus americanus, 1%; 1 
seed Cladium sp?, trace; and ground-Up vegetable matter, 16%. The others con- 
tained various shell -fish: blue mussels (Mytilus edulis), broken up gastropods 
{Litorina, etc.), with seeds of Cladium, Mariscoides, Potamogeton and Prosespinaca. 
I have seen Black Ducks feeding on acorns in a park near Boston in early April, 
and Dionne (1906), as well as Audubon, mention acorns as an article of diet. 
The typical stomach from our salt-marshes in winter contains no vegetable matter, 
but is one mass of very small shell-fish, mostly gastropods (snails). 
