RED-EYED BRONZED COWBIRD 465 



stone after stone, turning over the smaller ones, pushing aside those 

 which were somewhat larger, and merely raising slightly one side of 

 the biggest, to see what edible matter might lurk beneath them. 

 The Sumichrast's blackbirds and the great-tailed grackles joined in 

 this pursuit, but not so energetically as the cowbirds; for the grackles 

 especially preferred to hunt small creatures that lurked in the shallows, 

 where the other stone-turners rarely ventured. All four of these 

 blackish members of the troupial family turned their stones in exactly 

 the same fashion: the bird's head was lowered and the tip of its bill 

 inserted beneath the near edge of the stone and pushed forward, in the 

 line of advance of the bird. As the decisive push was delivered, the 

 bird's lower mandible was dropped somewhat and its bill held slightly 

 open. Whatever small animals lay concealed beneath the stone were 

 eaten, then the bird proceeded to move another." 



Behavior. — Skutch (MS.) remarks on their behavior: "As evening 

 fell, the red-eyed cowbirds and the Sumichrast's blackbirds finished 

 their supper gleaned from the stony flood plain and retired to roost in a 

 dense stand of young giant canes (Gynerium sagittatum) growing 

 behind the barren flats. Until they fell asleep, the blackbirds con- 

 tinued to utter a delightful variety of clear and soothing whistles, but 

 their companions the cowbirds were rarely heard." 



Voice. — Friedmann (1929) writes: 



The song is confined to the male and is quite similar to that of the ordinary 

 Cowbird (Molothrus ater) but wheezier, throatier, the individual notes shorter 

 and the preliminary guttural notes deeper. It may be written as follows ugh 

 gub tse pss tseeee. Frequently the three first notes are omitted and sometimes the 

 last two are run together. I have heard the song given by birds while flying 

 and also while on the ground. Strangely enough I never heard it from a bird in 

 a tree although Visher's experience (see above) was just the reverse. 



The call notes of the Red-eyed Cowbird are not yet well known and are worth 

 careful study. In my experience with this species, call notes were rarely heard 

 and the few that were noted were all of one type, a harsh, beady, almost rasping 

 chuck. This note seemed to be a feeding note and was used by both sexes. I 

 never saw or heard anything to indicate that the birds have any other call notes. 



Field marks. — The led-eyed cowbird is larger than the common 

 cowbird, nearly the size of Brewer's blackbird, with which it is often 

 associated, but the cowbird's eye is red, while that of the blackbird 

 is yellow; and the cowbird has a stouter, more conical bill than the 

 blackbird and its bronzy color is conspicuous, contrasting with the 

 violaceous-green wings and tail. The blood-red eye of this cowbird 

 is distinctive when near enough; and in the mixed flocks of blackbirds 

 it can often be recognized by its top-heavy appearance due to the 

 purling out of the feathers of the head and neck, forming a sort of ruff. 



Winter. — The red-eyed cowbird is only partially migratory in the 

 lower Rio Grande Valley. Merrill (1877) says; "Here they are com- 



