408 ANIMAL LIFE IN THE YOSEMITE 



for a short time and then fly off, all in the same g-eneral direction, over 

 heaps of boulders left by a gold dredger. Other pairs were arriving from 

 time to time over the same course. By following up this line of flight 

 we discovered the nesting area about a quarter of a mile distant in a long 

 dredger pond which supported at its iu-shore end an unusually dense 

 stand of tules, both living and dead. This trait of the Tri-colored Black- 

 bird to fly back and forth over a given air-course or 'highway' may thus 

 be used in determining the location of a nesting colony, even though the 

 latter may be a mile or more from the forage ground. 



At the colony numerous pairs of adults were perched about in the small 

 willows which grew on the shores of the pond. The males exhibited no 

 jealousy at one another's proximity, and each accompanied his mate as 

 the latter went in search of food for the nestlings. Zealous guarding of 

 the nesting precincts, which is so marked a trait in the behavior of the 

 male Red-wing, is not practiced by the Tri-color. There is not the need 

 for each and every male to remain at the nest while the female is absent ; 

 the nests are located so very close together that there are always enough 

 adult birds about the colony to sound an alarm should an enemy appear. 

 It would seem as though the Tri-colored Blackbirds had attained to a more 

 successfully communal stage of development in their domestic affairs than 

 have the Bi-colored Red-winged Blackbirds. 



The females did all the work of feeding the young; but despite their 

 burden they carried on the work in a surprisingly deliberate manner, 

 totally unlike the incessant activity which characterizes so many birds 

 when rearing their broods. Each stage in the proceeding was accomplished 

 in a leisurely manner, and the birds rested at each end of the journey 

 to and from the forage grounds, and both before and after feeding the 

 young. While perched near the colony, adult birds of both sexes uttered 

 the single harsh call note at short intervals, and the males from time to 

 time gave their short scolding song, which sounded somewhat like the words 

 get out uttered quickly and harshly. Individual females were continually 

 entering and leaving the tules, and as each approached her own nest the 

 squealing calls of the young, skee, skee skeeeee, would increase in volume 

 and then suddenly cease as their wants were satisfied. The nests were 

 not examined closely, but it was evident that most of the eggs in the 

 colony had hatched ; still no young were seen out of the nest. 



