796 U.S. NATIONAL MUSEUM BULLETIN 23 7 part 2 



Revere, Mass., and was observed trying to copulate with a female 

 sharp-taU (Ludlow Griscom, pers. comin.). In New Jersey, W. 

 Moutagna (1942a) collected a male sharp-tail and a female seaside 

 apparently in copulation. Sage, Bishop, and Bliss (1913) recorded 

 a female hybrid of the sharp-tail and the seaside taken near New 

 Haven, Conn., May 1, 1890; I have examined this specimen in the 

 Museum of Comparative Zoology and agree with their diagnosis. In 

 1957 in an area occupied by both species in Barnstable, Mass., 

 I studied a bird which appeared identical with this specimen and 

 which I believe was another hybrid. No hybrid of either the sharp 

 tail or the seaside with any other species has ever been recorded, to 

 the best of my knowledge. 



It seems likely that the southern Atlantic coast, where all five sub- 

 species of the sharp-tailed sparrow now winter, was the Pleistocene 

 breeding refuge of the then undifi'erentiated species. With the retreat 

 of the glacial front, the sharp-tails followed the development of 

 marshes northward along the coast, and eventually responded to the 

 new environments by subspeciating. W. J. Beechor (1955) pointed 

 out that the existence of the now isolated James Bay and Nelson's 

 races may be accounted for by the former occurrence of a marine 

 corridor via the St, Lawrence and either the Ottawa or Saguenay 

 Rivers to James Bay, and thence westward to Lake Winnipeg, this 

 being permitted by the temporary downward warping of the earth's 

 crust by the weight of the ice. There is both geological and botanical 

 evidence for the existence of such a corridor. 



Spring. — In spring it is impossible to teU when the first sharp-tails 

 leave their wintering grounds on the southern Atlantic coast and 

 difficult to identify the first arriving migrants because of possible 

 confusion with wintering stragglers. Sprunt and Chamberlain (1949) 

 stated that all have left South Carohna by May 16. The latest record 

 for coastal Alabama is May 16, 1911 (Imhof, 1962). Witmer Stone 

 (1937) believed the first migrants appeared at Cape May as early as 

 April 11. A. D. Cruickshank (1942) reported the first on Long Island 

 at about the same time, although the first real wave never comes prior 

 to April 25 and the bulk of the birds arrive in May. In Massachusetts 

 (Griscom and Snyder, 1955) the earliest strays have appeared by 

 May 9, these being scattered single birds, the main arrival being 

 between May 23 and June 1. The date of arrival in Massachusetts 

 seems to be correlated with the new green growth of Spartina; when 

 this reaches about six inches, the sharp-tails appear. 



The eastern sharp-tailed sparrow migrates along the coast. I have 

 seen only one specimen from a truly inland locality, a bird taken May 

 30, 1952, in Wayland, Mass. The species migrates at night, and I 



