204 Saunders, An Ecological Bird Study. lApril 



The large number of Brewer's Blackbirds was partially accounted 

 for by the fact that a colony of thirteen pairs was nesting in the 

 area. These birds did not live entirely in this association, but did 

 much of their feeding in the grass meadow association. After their 

 nesting was over, in July, they gathered into flocks with their 

 young and were frequently found in the Cottonwood groves. I 

 have little doubt about the correctness of my count of this species. 

 It was easy to observe all the forty-four individual birds at any 

 time while they were nesting, if the whole brush area was covered 

 thoroughly. This is because of the habit the birds have of pro- 

 testing at anyone's intrusion near their nests, always keeping 

 together in pairs, and following him about, hovering over his head, 

 or perching conspicuously on the bushes. Whenever I entered the 

 colony, I was always able to count the thirteen pairs of birds. 

 Each pair kept so close together that I was able to count them in 

 that way instead of individually. Ten of the nests of this species 

 were actually found, nine in the colony, and one outside of it. 



With the Cowbirds, I found considerable difficulty in getting a 

 correct count. Since they had no fixed nests of their own, and 

 wandered about from day to day, on and off the area, I found that 

 an accurate count was out of the question. They were found most 

 frequently in the cinquefoils, but also fed considerably in the grass 

 meadows, and were occasionally seen in the cottonwoods, where 

 observations showed that they laid their eggs frequently. My 

 estimate of the numbers of this species, is merely the result of my 

 judgment, after observations on the area throughout the nesting 

 season. I believed six pair to be the average numbers found on the 

 entire area during the nesting season, and counted four of these in 

 the cinquefoil brush and two in the cottonwoods. I actually 

 found but two eggs of the species in the cinquefoils, one in the nest 

 of a Brewer's Blackbird, and the other in the nest of a Western 

 Vesper Sparrow. 



Both the Vesper and Clay-colored Sparrows were counted by 

 noting the singing of the male birds as was the case with the species' 

 nesting in the grass meadows. The females were not commonly 

 seen. One nest of the Vesper Sparrow was found and none of the 

 Clay-colored Sparrow. Both birds of the pair of Western Yellow- 

 throats were seen, and the male was observed in song frequently. 



