58 BIRDS OF ALABAMA 



rootstocks of ditchgrass (Ruppia maHtima) and on mollusks. 

 One individual had consumed 400 snails at one meal. 



CANVAS-BACK: Aristonetta valisineria (Wilson).** 



State records. — The famous and much-prized canvas-back, 

 though formerly plentiful, is now rather uncommon in the 

 State. It is reported to occur in winter at Muscle Shoals in 

 the Tennessee River, at Orange Beach, and near Autaugaville. 

 At the last named place a flock of 7 was seen on a mill pond, 

 November 28, 1911, and 1 was secured two days later. Dur- 

 ing January, 1912, about a dozen remained in the vicinity 

 several weeks, visiting the mill pond and other ponds and 

 marshes near Bear Swamp (Golsan). In Mobile Bay the 

 species is said to be fairly common; Dr. S. C. Frederic re- 

 ported seeing 6 there, November 7, 1915, and Addie Taylor 

 saw 12 in Chuckvee Bay, about November 15, 1915. 



General habits. — The canvas-back is a diving duck and, like 

 the redhead, feeds in deep water, usually gathering into good- 

 sized flocks. Its flight is exceedingly rapid, usually in a 

 straight line and often at a great height. It is a very wary 

 bird, but may under favorable circumstances be decoyed 

 within range. 



Formerly, when much more abundant than at present, vast 

 flocks were accustomed to gather in the waters of Chesapeake 

 Bay, Maryland, and upon suddenly taking wing they produced 

 a noise like thunder. The canvas-back has long been famous 

 for the high quality of its flesh, which was believed to be due 

 to its habit of feeding on wild celery. McAtee has shown, 

 however, that while the bird does consume considerable quan- 

 tities of this plant, it feeds to a large extent also on other 

 plants, notably pondweeds (Potamogeton). In the shallow 

 lakes of southern Louisiana he found this bird (which in more 

 northern regions prefers comparatively deep water) in abun- 

 dance, living largely upon the tubers of a species of arrowhead 

 known as the wild potato* 



Food habits. — The canvas-back feeds extensively on wild 

 celery (Vallisneria spiralis), pondweeds, widgeon-grass or 



•'Blarila Tali^ineria of the A. O. U. Check-list.; for change of name see The Auk 

 vol. 3«, p. 267, 1919. 



*McAt€e, W. L., Bull. 465, U. S. Dcpt. Agr., p. 21, 1917. 



