86 
BULLETIN OF THE NUTTALL 
arrive from the South, and M. ceneus gather in flocks by themselves, 
and wait for their victims to build. The males have now a variety 
of notes, somewhat resembling those of the common Cowbird 
{Molothrits 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 pufling out their feathers, as above noted, strutting up and 
down, and nodding and bowing 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. pecoi’is). 
My first egg of M. ceneus 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 
w’ere found in nests of the Bullock’s, Hooded, and small Orchard 
Orioles (Icterus spurius var. affinis). It is a curious fact 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 wdthin 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 the three 
species in one nest, and had the latter been near the fort, where I could have 
visited them daily, I should not have taken the eggs. It is probable, however, 
that M. ceneus would have disposed of the young Dw’arf Cowbird as easily as of 
the young Orioles. 
