BIRDS OF ESSEX COUNTY. 135 



55 [147] Aythya vallisneria (Wils.). 

 Canvasback. 



Very rare transient visitor ; November 1 3 to . 



There is a pair of these birds in the collection of the Boston Society of 

 Natural History, shot at Newburyport about sixty years ago and presented by 

 Dr. Samuel Cabot. 1 Mr. Dodge tells me that one was shot in the Topsfield 

 marshes by Mr. B. I. Quinby several years ago, and Dr. Phillips reports one 

 shot at his stand at Wenham Lake on November 13th, 1902, this being the 

 first one shot and the second observed there. This specimen is a young male. 

 It must be remembered that a very different Duck, namely the Eider, is some- 

 times called "Canvasback" in Essex County. 



The field marks of the Canvasback are given under the Redhead. 



56 [148] Aythya marila (Linn.). 



Scaup Duck; Greater Scaup; "Bluebill"; " Bi.uebill Widgeon"; 

 "Widgeon"; "Blackhead." 



Common transient visitor in the autumn, rare in the spring ; March 27 to 

 April 17 ; September 18 to December 26. 



The common name of this bird among the gunners of Essex County is 

 "Bluebill," or "Bluebill Widgeon," or "Widgeon," never Scaup. It is possible 

 that the bird may occasionally spend the winter, as it is found in Boston Harbor 

 at this season. While the Lesser Scaup seems to prefer the ponds, this species 

 is found in salt-water estuaries and sometimes in the sea, as well as in the ponds. 



Dr. Phillips, in his records for Wenham Lake, has not distinguished 

 between the Greater and the Lesser Scaups during the first four years. He 

 thinks, however, that the proportion during these years was about three of the 

 Greater to one of the Lesser. In 1900, 22 were shot there; in 1901, 18; 

 in 1902, 49; in 1903, 39. In 1904, however, when the two species were care- 

 fully distinguished, his records show the Lesser to be much the commoner. 

 Dr. Phillips feels sure that this was an unusual year. Of 48 Scaup shot in 

 1904, only three were of the larger species, the rest being the Lesser Scaup. 



1 Samuel Cabot: Proc. Boston Soc. Nat. Hist., vol. 2, p. S9, 1846. 



