86 BULLETIN OF THE NUTTALL 



arrive from the South, and M. ceneus gatlier in flocks b}' themselves, 

 and wait for their victims to build. The males have now a variety 

 of notes, somewhat resembling those of the common Cowbird 

 {Molothrus pecoris), but more harsh. During the day they scatter 

 over the surrounding country in little companies of one or two 

 females and half a dozen males, returning at nightfall to the vicin- 

 ity of the picket lines. While the females are feeding or resting in 

 the shade of a bush, the males are eagerly paying their addresses 

 by puffing out their feathers, as above noted, strutting up and 

 down, and nodding and bownng in a very odd manner. Every now 

 and then one of the males rises in the air, and, poising himself two 

 or three feet above the female, flutters for a minute or two, follow- 

 ing her if she moves away, and then descends to resume his puffing 

 and bowing. This habit of fluttering in the air was what first 

 attracted my attention to the species. In other respects their 

 habits seem to be like those of the eastern Cowbird [M. pecoris). 



My first egg of J/, cejieus was taken on May 14, 1876, in a Car- 

 dinal's nest. A few days before this a soldier brought me a similar 

 egg, saying he found it in a Scissor-tail's (Milvulus) nest ; not rec- 

 ognizing it at the time, I paid little attention to him, and did not 

 keep the egg. I soon found several others, and have taken in all 

 twenty -two specimens the past season. All but two of these 

 were found in nests of the Bullock's, Hooded, and small Orchard 

 Orioles {Icterus spurixs var. affinis). It is a curious fixct that al- 

 though Yellow-breasted Chats and Red-winged Blackbirds breed 

 abundantly in places most frequented by these Cowbirds, I have 

 but once found the latter's egg in a Chat's nest, and never in a Red- 

 wing's, though I have looked in very many of them. Perhaps they 

 feel that the line should be drawn somewhere, and select their 

 cousins the Blackbirds as coming within it ; the Dwarf Cowbirds 

 are not troubled by this scruple, however. Several of these parasitic 

 eggs were found under interesting conditions. On six occasions I 

 have found an egg of both Cowbirds in the same nest ; in four of 

 these there were eggs of the rightful owner,* who was sitting ; in 

 the other two the Cowbird's eggs were alone in the nests, which 



* It would be interesting to know what would have become of tlie three 

 species in one nest, and had the latter been near the fort, where I could liave 

 visited them daily, I should not have taken the eggs. It is probable, however, 

 that M. ccncus would have disposeil of the young Dwarf Cowbird as easily as of 

 the young Orioles. 



