A winter feeding experiment on an island Song Sparrow population

摘要: Supplemental food, in the form of millet seed, was provided to half an island Song Sparrow population during 1978-1979 winter test if food influenced: (1) overwinter survival; (2) wights; (3) breeding density 1979 and (4) performance.Territorial males were most dominant at feeders may have restricted access young feeders. Young females subordinate Adult survival not affected by supplementary but higher than 6 previous years seen visit survived better more variable weight on unfed fed end. The increased 38% from 1978 1979, it is known how much this increase resulted addition. Pairs birds with their territories began lay 25 days earlier control pairs, delayed longer controls before a second attempt. One-year old significantly later adults area, area. Other measures performance supplemental food. Winter be important male territorial behaviour less previously supposed limiting numbers Mandarte Island population.