100 U.S. NATIONAL MUSEUM BULLETIN 233 



Magnolia Warbler 



Dendroica magnolia (Wilson) 



The magnolia warbler has been recorded rather seldom as a cow- 

 bird victim, a fact which suggests that probably it is parasitized 

 infrequently. Eaton (1914, p. 410), however, wrote that the cow- 

 bird "seems to make a specialty of presenting this Warbler with one 

 or more of its eggs, generally punctm-ing the eggs of the Magnolia 

 before leaving the nest." Unfortunately, Eaton did not support this 

 statement with explicit data, and such evidence has not been found 

 in the literature. Higgins (1894, p. 106) collected a parasitized nest 

 near Cincinnatus, New York, and a second set that later became 

 part of the J. P. Norris collection. Other parasitized sets of eggs are 

 in the collections of the American Museum of Natural History and 

 the Chicago Natural History Museum. The late H. Mousloy wrote to 

 me that he had found a cowbird's egg in a magnolia warbler's nest 

 near Hatley, Quebec. All in all, only 17 records have been noted, 

 ranging from Quebec, Prince Edward Island (Mills, 1958), Ontario, 

 and Saskatchewan to Massachusetts, New York, Pennsylvania, 

 Michigan, and Minnesota. In southern Quebec, in the course of 

 almost GO years, Terrill (1961, p. 7) found 147 nests of this warbler, 

 of which 6 contained cowbird eggs. 



All the records refer to the nominate, eastern race of the brown- 

 headed cowbird, except one from Saskatchewan, wherein the race 

 artemisiae is involved. This was found by Street {in Houston and 

 Street, 1959, p. 159) at Nipawin, Saskatchewan, on June 27, 1934. 



Cape May Warbler 



Dendroica iigrina (Gmelin) 



Many years ago, the late J. H. Bowles wrote to me that he had a 

 distinct recollection of having seen a set of eggs of this warbler con- 

 taining one of the cowbird, but he could not recall where or when it 

 was collected or in whose collection it was when he saw it. Because 

 of this lack of precise data I have kept this statement in my unpub- 

 lished notes, waiting for a more completely documented case, but 

 no other instance has yet been reported. Without a specified locality, 

 one cannot say which of the two possible races of the cowbird was 

 involved. Since the Cape May warbler nests high up in evergreen 

 trees, it is not likely to be recorded to any extent as a cowbird host. 



Black -throated Blue Warbler 



Dendroica caerulescens (Gmelin) 



This is a very infrequent host of the brown-headed cowbird. Only 

 10 records have been noted — distributed from Ontario and Quebec to 

 Rhode Island and New York. Hathaway (1913, p. 557) saw a female 



