674 BULLETIN 203, UNITED STATES NATIONAL MUSEUM 



the young parasites were four addled eggs of the warbler. If some 

 of the rightful eggs hatch, the young are usually starved or suffocated 

 by the young cowbirds, although nests are occasionally found in which 

 one or more of the young survive along with the interloper. 



In discussing the effect of this parasitism on the redstart Friedmann 

 adds : "When a cowbird is raised by a one-brooded species such as the 

 redstart it represents the total product of its pair of foster-parents 

 for the year. The loss here is a very decided one if we consider the 

 food consumed by one cowbird and that which would have been eaten 

 by four Redstarts, However, judging from the constancy of the 

 numerical status of the Redstart from year to year it seems as though 

 three of the four young would succumb anyway to various dangers 

 before the next year. Also we must remember that the Redstart is in 

 many places more abundant than the cowbird." 



Joseph J. Hickey (1940) writes : "Males were silent in the presence 

 of female Cowbirds, but females reacted with sharp hisses, a rapid 

 snapping of the bill and much spreading of the tail." Friedmann 

 (1929) writes: "On July 2, 1921, a young Cowbird, full grown in 

 size and fully fledged was seen following a Redstart and begging 

 for food from it. The Redstart paid absolutely no attention to it 

 although several times the two were very close together. All this 

 time the Redstart was busy gathering food and when it had as much 

 as it could carry it flew off and the young Cowbird did not follow." 



Dayton Stoner (1932) gives an account of an interesting experience 

 of the behavior of redstarts as follows: "I saw one female carrying 

 food for young. Another female was seen feeding a young cowbird 

 that was out of the nest and able to fly, while an adult female cowbird 

 sat on a limb nearby and apparently watched the proceedings. The 

 female cowbird did not offer the young one any food, but after the 

 latter's wants had been satisfied in some measure by the diminutive 

 redstart, she moved close to the young one and at least appeared to be 

 solicitous of its welfare. But any maternal solicitude involving real 

 care of the young was utterly foreign to this parasitic bird." 



Fall. — The redstarts start migrating from the most northern sec- 

 tions of their nesting range in August but it is well into September 

 before the last individuals leave these outposts. The individuals 

 breeding in British Columbia near the Pacific Ocean do not follow 

 the Pacific flyway but retrace their path across the mountains to the 

 interior and leave the United States between Texas and Florida, their 

 point of entry. In recent years an increasing number of redstarts 

 have nested in Washington and Oregon, and there are many records 

 of occurrence, especially during the time of migration, throughout 

 California and southward. This may mean a building up of a tend- 

 ency of the individuals nesting in the northwest to use the Pacific 



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