174 DAVENPORT ACADEMY OF SCIENCES. 



It is doubtful whether the Redhead nests in Iowa at the present 

 time, as no observers have reported the species in summer during 

 recent j^ears. G. H. Berry reported it as a "rare summer resi- 

 dent" at Spirit I^ake in 189 1-2. In 1885 the most southerl}' 

 breeding reported to W. W. Cooke came from Clear I^ake, Iowa 

 (Bird Migr. in Miss. Val., 70). P. B. Peabody took a set of eggs 

 at Heron L,ake, Minn., June 22, 1895, (061., xii, 8, 1895, 126). 



The Redhead is quite often confused with the Canvas-back by 

 untrained observers, but the two species are easily distinguished in 

 any plumage. The Redhead's forehead arches abruptly up and 

 away from the base of the bill, while the Canvas-back's bill slopes 

 gradually up to the top of the head in line with the sweep of the 

 forehead, somewhat like a Goose's in shape. 



The Redhead and Canvas-back are among the few species of 

 ducks which usually build their nests directly over the water. 

 All nests which I have examined resembled those of the American 

 Coot, being a platform of dead rushes bent down over the water. 



41. (147). Aythya vallisneria (Wils.). Canvas-back 



The Canvas-back, from its supposed preeminence as a table duck, 

 has been hunted so pesistently all over the United States that it 

 now appears to be rarely seen in Iowa even as a migrant. Most 

 observers consider it as a rare migrant, or irregular. Only three 

 observers report it as at all common. In the Keokuk district 

 Praeger gives it as a common migrant; Currier, in L,ee county, 

 as a migrant, irregular in abundance. Dr. Trostler lists it as an 

 abundant migrant in Pottawattamie and Mills. 



There are no records of the Canvas-back nesting in Iowa, though 

 the birds may linger late in the .spring in favorable localities. In 

 a letter of May 22, 1901, M.E.Halvorsen wrote me: "There are 

 two or three pairs of Canvas-backs that seem to be nesting down 

 around the Buffalo Fork swamp, but I have not been able to find 

 any nests yet" (Rake, Winnebago county). 



When feeding upon wild celery the flesh of the Canvas-back is 

 said to acquire a peculiarly fine flavor. "Mr. Skavlem of Janes- 

 ville has .shown that the so-called 'celerj^ buds' upon which these 

 ducks often feed are no part of the plant Vallisneria spiralis, but 

 the bemmae or nutlets of one of the pond-weed family {Naiad- 

 aceo').'" (Birds of Wis., 1903). 



