156 NORTH AMERICAN BIRDS. 



hlackburnia', J), pennsylvanica and D. discolor, Seiurus aurocapilhis, Setophaga 

 ruticilla, Cyanospiza cyanca, Contopus virens, etc. I have also known of 

 their eggs having been found in the nests of Vireo belli and V. pusillus, and 

 Cyanospiza amcena. Dr. Cooper has found their egg in the nest of Icteria 

 virens ; and Mr. T. H. Jackson of West Chester, Penn., in those of Empido- 

 nax acadicus and Pyranga rubra. 



Usually not more than a single Cowbird's egg is found in the same nest, 

 though it is not uncommon to find two ; and in a few instances three and 

 even four eggs have been met with. In one instance Mr. Trippe mentions 

 having found in tlie nest of a Black and White Creeper, besides three eggs 

 of the owner of the nest, no less than five of tlie parasite. Mr. H. S. Eod- 

 ney reports having found, in Potsdam, N. Y., May 15, 1868, a nest of Zono- 

 tricJiia hucophrys of two stories, in one of which was buried a Cowbird's egg, 

 and in the upper there were two more of the same, with three eggs of the 

 rightful owners. In the spring of 1869 the same gentleman found a nest of 

 the Sayornis fuscus with three Cowbird's eggs and three of her own. 



Mr. Vickary, of Lynn, found, in the spring of 1860, the nest of a Seiurus 

 aurocapillus, in which, with only one ^g^ of the rightful owner, there were 

 no less than four of the Cowbird. All five eggs were perfectly fresh, and had 

 not been set upon. In the summer of the preceding year the same gentle- 

 man found a nest of the Eed-eyed Vireo containing three eggs of the Vireo 

 and four of the Cow Blackbird. 



How the offspring from these eggs may all fare when more than one of 

 these voracious nurslings are hatched in the same nest, is an interesting 

 problem, well worthy the attention of some patiently inquiring naturalist to 

 solve. 



The Cow Blackbird appears in New England with a varying degree of 

 promptness, sometimes as early as the latter part of ]\Iarch, and as frequently 

 not until tlie middle of April. Nuttall states that none are seen in ]\Iassa- 

 chusetts after the middle of June until the following October, and Allen, 

 that they are there all the summer. My own observations do not correspond 

 with the statement of either of these geutlemen. Tliey certainly do become 

 quite rare in the eastern part of that State after the third week in June, but 

 that all the females are not gone is proved by the constant finding of freshly 

 laid eggs up to July 1. I have never been able to find a Cow Blackbird in 

 Eastern Massachusetts between the first of July and the middle of Sep- 

 tember. This I attribute to the absence of sufficient food. In the Cambridge 

 marshes they remain until all the seeds have been consumed, and only reap- 

 pear when the new crop is edible. 



This Blackbird is a general feeder, eating insects, apparently in preference, 

 and wild seed. They derive their name of Cow Blackbird from their keep- 

 ing about that animal, and finding, either from her parasitic insects or her 

 droppings, opportunities for food. They feed on tlie ground, and occasion- 

 ally scratch for insects. At the South, to a limited extent, they frequent 

 the rice-fields in company with the Eed-winged Blackbird. 



