8 BULLETIN 862, U. S. DEPARTMENT OF AGRICULTURE. 



MISCELLANEOUS VEGETABLE POOD, 2.61 PER CENT. 



A large number of miscellaneous items made up the remainder of 

 the gadwall's vegetable food. The stomach of one duck from the 

 mouth of Bear River, Utah, was filled with remains of the stems, 

 leaves, and seeds of picklegrass (Salicornia ambigua). A young duck 

 from the same region had made a meal of willow catkins (Salix sp.). 

 Several gizzards from the wooded swamps of Arkansas contained 

 fragments of scales from the cones of bald cypress (Taxodium dis- 

 ticJium), and one was entirely filled with galls from cypress leaves. 

 Many from this region also contained the seeds, or fragments of 

 seeds, of grapes (Vitis sp.), hackberry (Celtis sp.), holly (Hex sp.), 

 and sumachs (Rhus spp.). Seeds of beggar ticks, or bur marigold 

 (Bidens sp.), water milfoil (Myriophyllum sp.), bottle brush (Hip- 

 puns vulgaris), crowfoot (Ranunculus sp.), water pennywort (Hydro- 

 cotyle sp.), dodder (Cuscuta sp.), myrtle (Myricasp.), bur reed (Sparga- 

 nium sp.), heliotrope (H eliotropium indicum), and many others, eaten 

 in small quantities, completed the vegetable food of the species. 



Animal Food. 



As has been stated previously, the proportion of animal food 

 taken by the gadwall is very small, amounting to only 2.15 per cent 

 of the contents of the stomachs examined, exclusive of the few 

 scattered items taken during the months -from April to August. 

 In these the presence of several stomachs of ducklings caused the 

 average percentage of animal food to run considerably higher. The 

 figures given were compiled from the contents of the 362 stomachs 

 collected during the fall and winter months, from September to 

 March. 



MOLLUSKS (MOLLUSCA), 1.6 PER CENT. 



About three-fourths of the animal food of the gadwall, or 1.6 per 

 cent of the total, consisted of mollusks. In 6 April stomachs (not 

 included in this average) they amounted to 15.83 per cent of the 

 monthly food. In the fall and winter months they ranged from 

 nothing in September to 4 per cent in January. Eight species of 

 snails were identified, while there were unidentified fragments of 

 snails in 5 stomachs and unidentified bivalves in 3. The most 

 important snail was Neritina virginea, which is very common on the 

 Mississippi Delta and constitutes one of the principal items of food 

 of many species of ducks wintering in that region. This had been 

 eaten by 25 gadwalls and ranged from a mere trace to 70 per cent of 

 the food present. 



tNSECTS (iNSECTA), 0.39 PER CENT. 



Insects amounted to only 0.39 per cent of the total food. These 

 consisted of caddisflies and their Larvae (Phryganoidea), 0.19 percent; 

 flies and their larvae (Diptera), 0.07; bugs (Hemiptera), 0.05; 



