Site infidelity in song sparrows

摘要: Abstract In each of 4 years study a breeding population song sparrows ( Melospiza melodia ) approximately two-thirds the males holding territories at beginning season had abandoned those before end and overall 83% were never seen again. Males more likely to abandon territory following nest failure but some individuals left after success remained failure. Indirect evidence suggested that quality also influenced male's decision stay or go. Data on nesting both birds move benefit from their actions. Between years, showed same lack site fidelity, return which they been successful. Females little fidelity within seasons, although for reasons as males, appeared independently mate. Only one 146 banded nestling was ever resighted an adult. Together, low adult natal philopatry indicate much higher level outbreeding than has estimated previously this species. We discuss implications these results propose that, rather being evolved attribute maintain optimal inbreeding, is conditional strategy related intraspecific competition territories.