CANVASBACK 



153 



being built up six incbes above the water, and tbe inner cavity being 

 about eight inches across by four deep. It can be seen, therefore, 

 that the Canvasback is unlike the IVIallard, Teal, and other fresh water 

 ducks, in that it chooses growths of reeds rather than grass as locations 

 for nests. Grav down is used to line the nest. 



10607 



Fig. 21. Side of bill and head of Canvasback. Natural size. 



Note low, sloping forehead. Compare with high forehead 

 of Eedhead (fig. 20). 



Fig. 22. Side of foot and tarsus of Canvas- 

 back. Natural size. 



Note presence of broad lobe on hind toe (com- 

 pare with figs. 11 and 38), and that tarsus is 

 shorter than middle toe without claw (compare 

 with fig. 37). 



The finding of the eggs of other ducks in the nests of the Canvas- 

 back appears to be of common experience. Bent (loc. cit.) found one 

 or more eggs of the Ruddy Duck or of the Redhead in every Canvas- 

 back nest examined by him, but did not find the eggs of the Canvas- 



