FOOD HABITS OF SHOAL-WATER DUCKS. 39 
Duckweeds are especially abundant on the still waters of southern 
cypress swamps, often covering the entire surface and furnishing 
an abundant supply of food for the ducks wintering there. The 
stomachs of many of the wood ducks taken in such localities in 
Louisiana and Missouri were filled almost entirely with duckweed 
plants, and the gullets also of several of them were crammed. A 
few ducks from other localities, as Arkansas, Illinois, New York, 
and Ontario, had taken this food in considerable quantities. Alto- 
gether, 99 of the wood ducks had been feeding upon greater duck- 
weed (Spirodela polyrhiza) and 187 on other duckweeds (Lemna spp.). 
PINE FAMILY (PINACEAE), 9.25 PER CENT. 
The pine family was represented in the wood duck stomachs 
entirely by cone scales and galls from the bald cypress (Tazxodium 
distichum), with possibly a few from pond cypress (7. ascendens). 
This peculiar diet is indulged in by this duck to a much greater 
extent than by any other, or probably by any other bird. The 
cones of cypress are about an inch in diameter, compact and nearly 
spherical, and when fully mature break up into angular woody 
scales, each containing a seed. It is these scales which the ducks 
pick up and which when ground by the powerful gizzards yield a 
starchy food material in the seeds. Several kinds of insect galls 
found on different parts of cypress trees also were eaten by the 
ducks. The kind most commonly taken was a hard, spherical gall 
‘made in the cone by a species of cecidomyid fly (Retinodiplosis 
taxodiz). Cypress galls of various kinds were found in 35 of the 
stomachs, while 183 contained cone scales, some to the extent of: 
100 per cent of the contents. 
SEDGES (CYPERACEAE), 9.14 PER CENT. 
Sedge seeds are common articles of food of the wood duck, though 
not so much so as of most of the ducks which inhabit open manrsiitet 
A species of bulrush (Scirpus cubensis) which grows in swamps in 
the Gulf States far outweighed in importance any of the other sedges 
identified in the stomachs examined. The seeds of this plant were 
found in 47 stomachs, in several instances from 3,000 to more than 
5,000 being present. Fifteen wood ducks had eaten the large, 
beaked seeds of pollywog or beaked rush (Rhynchospora corniculata). 
Tn a series of 3 stomachs from Okefenokee Swamp, Georgia, these 
seeds constituted 10, 17, and 35 per cent, respectively, of the con- 
tents. The small, hard, spherical seeds of saw grass (Cladiwm 
effusum) were present in 15 stomachs, those of nut rush (Sclerié 
sp.)in 3. Seeds of chufas (Cyperus spp.) were found in 45 stomachs, 
usually in small numbers, and in one stomach from Minnesota was 
one large tuber of chufa (Cyperus esculentus). Seeds of the genus 
