16 BULLETIN 720, U. S. DEPARTMENT OF AGRICULTURE. 
seeds of prickly smartweed (Polygonum sagittatum) were taken from 
a single stomach. The seeds and tubers of sedges compose the next 
largest item, namely, 6.34 per cent. Seeds of waterlilies and coontail 
make up 3.11 per cent and seeds, stems, and foliage of pondweeds and 
widgeon-grass, 1.6 per cent. Other items of vegetable food worth 
mentioning are bayberries and seeds of buttonbush. 
ANIMAL Foop. 
As is true of both of its close relatives, the southern black duck 
consumes more mollusks than any other kind of animal food. These 
shellfish compose five-eighths of the animal diet and nearly 27 per 
cent of the whole food. Snails as large as one inch in diameter were 
among those eaten. Insects, making up less than a third as much of 
the food, are next in importance. Dragonfly nymphs, rarely adults, 
water bugs, caddis larve, a variety of beetles, and flies, including 
horsefly larve, are the principal items taken. Crustacea, chiefly 
crawfishes, contribute 2.77 per cent of the food, and fishes, no doubt 
small worthless kinds, 2.57 per cent. 
TaBLE I.—Items of vegetable food identified in stomachs of mallard ducks and the number 
in which found. 
Southern 
: Common] Black 
Kind of food. black 
mallard. duck, ducks 
otal numperiof stomachs examined 8.2.2.2 8e-0 o nee eee eee 1, 725 622 51 
SUBKINGDOM EUTHALLOPHYTA. 
ROA oUKG Vevat a0 (6 REY Kets heen RE ea ate WR ae EE ne ARs OO SS noase 21 OL sata ee 
CRATCISD = (GHAUS Ke STS) ete sea ee ede ca cre eee A Payee 29 2. | ose See 
Fucus sp. (seaweed).........- fee Desk Sines RE RR te Nie ay nee, = ee Ry is ee ee he See 
SUBKINGDOM BRYOPHYTA. 
HiIccrellasp. oat pe livieEWwOLb) ==. aes eee ee eee eee eee (4 eee Se SA eee woe 
IMIOSS a Eke os SS css hee ees Sse acta ore ge ec es ne eet ee 1 Fl SRR Sees nostic 8 
SUBKINGDOM PTERIDOPHYTA. 
Marsileacez. 
Marsilea vestita (pepperwort)......-..-.---- Ste ee a noted Sapo ee 3 3/2. 22st ee 
Marsiled Sp..(pePPeCLWOrk)). ooo se ep tere eee eee 7 ol is EE S| RR coo Se 
Equisetacez. 
i GUAsetum’Sp.|(MOrsetail) S25 eee = te ee ree eee 1 ees ees sero 
SUBKINGDOM SPERMATOPHYTA. 
Pinacee. 
Pinusiceaaleblollymine) ta. 2:. sees eee eee ee eee 7A a a eA al ee ea eS 
IPINVUSisps (pine), “Meedles ve. ...c3osc- sae es ee eee eee eee ae | eee 2 bi Sos eee 
PAcearsp-1(Spruce),;needles,..22 422 Sole seek See ee eee ene ane 1 OY ioe sea! 
PROLOG IMI SiiChim (bald Gy PreSS)/. 550 eee eee eee 113 i a ee 
Paroduum disiichun (bald cypress), galls o. .s se scemem eee eee | 60. cae SS eee 
Sparganiacez. | 
SPULGMIUULINACILAnOCladiLimn, (DUE TECU) = ce. a heme eee =e eee 6 BY eee 
SPAUngGAanvuLmicunyconrpum (pDULTeed)\. .-.- 422 22s eee eee eee ee | 25 2 
SDATGONUENE SP (DUET OOO) Ke are arci-in cielo alele cree ere epee enines eee eRe eee 1 
