BED-WINGED BLACKBIRDS 403 



Yosemite Valley proved to belong to a race (aciciilatus) recently (1915) 

 described from the Kern Valley east of Bakersfield and until now not 

 known to breed in any other locality. 



As soon as the flocks begin to break up, the males commence courting 

 and their displays are carried on with little cessation from daylight to 

 dark throughout the nesting season. For this they seek some open sit- 

 uation, never far from the favorite swampy haunts. The male lowers 

 and opens his tail in wide fan shape, spreads and droops his wings until 

 the tips reach to or below his feet, raises his red wing patches outward 

 and forward like a pair of flaming brands, and having swelled out as large 

 as possible, utters his curious throaty song, tong-Ieiiy-lee. Usually this 

 is done while he is perched ; less often he mounts into the air and flies 

 slowly over a circling course without departing far from the object of 

 his attention. Interspersed between songs the bird gives other notes, a 

 sharp check or cJmck, a shrill whistle, or a scolding chatter. He closely 

 guards the immediate nesting precincts and tries to drive away all sorts 

 of intruders, including rival males. He even assists in demonstrations 

 against human invaders. When the female is building the nest he often 

 accompanies her as she goes for nesting material. But this is about the 

 extent of his participation in the family w^ork. Some doubt exists in the 

 minds of naturalists as to the strength of the marital tie among the Red- 

 wings even during the nest-building period. We think it likely that it 

 varies with different pairs. Polygamy may be practiced to some extent. 



On May 5, 1919, w^e established a camp on a gravelly bench beside 

 the Tuolumne River and about two miles southwest of Lagrange. A gold 

 dredger had worked on the river margin some years previously and had 

 left, in place of the fertile tillable plain of rich bottom-land soil, great 

 irregular heaps of rounded boulders of varying size, totally unsuited for 

 any use by humans. But the series of ponds in which the dredger had 

 floated had become converted into tule sloughs and these with the lines 

 of wallows and cottonwoods along the adjacent river afforded splendid 

 nesting situations for the Red-winged Blackbirds and other swamp-loving 

 species. Red-wings, both because of their numbers and their incessant 

 activity, were the conspicuous birds, but associated with them were Rails, 

 Least Vireos, Yellow Warblers, Yellowthroats, and Long-tailed Chats — 

 the usual marsh-border assemblage. 



The Red-wings in this colony (all of subspecies calif ornicus) were at 

 every stage in the cycle of nesting activities. Nests ready for eggs, fresh 

 eggs, incubated eggs, newly hatched young, and young fully grown were 

 found in different nests, although the account of foraging females given 

 below suggests that most of the young were by this time hatched. The 

 following table summarizes our findings May 6 to 9, 1919. 



