Return rates and dispersal distances of Welsh Pied Flycatchers Ficedula hypoleuca and factors that influence them

Abstract

This report presents an analysis of return and dispersal data collected for Pied Flycatchers Ficedula hypoleuca between 1992 and 2005 in Mid Wales. Overall, 53% of males, 42% of females, and 3% of nestlings returned to breed, most for only one or two years after being ringed. Many nestlings did not reappear in our study areas until two or more years after fledging. Return rates were marginally reduced in females and marginally enhanced in males by nest predation during the previous season but were significantly increased by the quality of the breeding territory and nesting success during the previous year. A fledging mass of 13 g appeared essential for the return of nestlings. Settling distances were longest in first-year (FY) adults, intermediate in older females, and shortest in older males. They did not change significantly during successive breeding seasons. Settling distances in one year were not significantly related to nesting success or territory quality during the previous breeding season. Those of FY breeding adults did not depend on the mass of the young birds at fledging. Nesting success declined with season in females, but not males. Population size has declined since 2000–02 and is associated with the increased use of our boxes by tits.