FOOD HABITS OF SHOAL-WATER DUCKS. 13 



FROGBIT FAMILY (HYDROCHARITACEAE), 5.75 PER CENT. 



The plants of the frogbit family eaten by the baldpate consisted of 

 wild celery (Vallisneria spiralis), which was found in 12 stomachs, 

 and waterweed (Philotria canadensis) , in 1 . Wild celery is a favorite 

 food of the canvas-back, redhead, and other deep-water ducks, but 

 as a rule it is not often found in the stomachs of ducks which do not 

 dive. However, the stomachs of baldpates from several different 

 localities were filled with wild celery leaves. This is very probably 

 due to a peculiar habit which the baldpate has of following the 

 diving ducks and feeding upon the leaves which they bring to the 

 surface. This habit was noted by Wilson and Bonaparte 6 as early 

 as 1831, and has been widely quoted by various writers since then. 

 According to these early ornithologists, "The widgeon is the constant 

 attendant of the celebrated canvass-back duck, so abundant in 

 various parts of the Chesapeake Bay, by the aid of whose labour he 

 has ingenuity enough to contrive to make a good subsistence. The 

 widgeon is extremety fond of the tender roots of that particular 

 species of aquatic plant on which the canvass-back feeds, and for 

 which that duck is in the constant habit of diving. The widgeon, 

 who never dives, watches the moment of the canvass-back' s rising, 

 and, before he has his eyes well opened, snatches the delicious morsel 

 from his mouth and makes off." It is probable that these observa- 

 tions are not entirely accurate, as the canvas-back is known to 

 feed chiefly upon the rootstocks of the plant; the baldpate merely 

 avails itself of the leaves thus cut off, brought to the surface, and 

 discarded by the canvas-back. 



WATER MILFOILS (HALORAGIDACEAE), 3.48 PER CENT. 



Water milfoil ( Myriophyllum sp.) had been eaten by 24 of the 

 baldpates, and bottle brush (Hippuris vulgaris) by 18. Many species 

 of ducks feed upon the seeds of these plants in small numbers, but 

 the baldpate so far as known is the only duck which shows any 

 particular fondness for their foliage. Several stomachs were found 

 to contain the seeds also, and in a very few instances they predomi- 

 nated over the foliage, but the bulk of the food derived from this 

 family of plants consisted of the tender leaves and stems. A series 

 of baldpates from Klamath Falls, Oreg., especially, had partaken of 

 the foliage of Myriophyllum in considerable quantities. 



DUCKWEEDS (LEMNACEAE), 2.2 PER, CENT. 



Like the gadwall, the baldpate shows less partiality toward the 

 duckweeds than do some other ducks. The stomachs of three 

 individuals, one each from Wisconsin, Utah, and Oregon, were 



e Wilson, Alexander, and Charles Lucian Bonaparte, Amer. Ornith., Ill, p. 198, 1831. 



