title: Demography of population recovery: survival and fidelity of peregrine falcons at various stages of population recovery.
abstract: Factors influencing vital demographic rates and population dynamics can vary across phases of population growth. We studied factors influencing survival and fidelity of peregrine falcons in south Scotland-north England at two stages of population growth: when the population was recovering from pesticide-related declines and density was low, and when it had largely recovered from pesticide effects and density was high. Fidelity was higher for: adults and subadults than for juveniles, females than for males, and juveniles and adults during the low-density than during the high-density study period. Survival was age specific, with lower survival for juveniles than for older birds (juveniles, 0.600 ± SE 0.063; subadults, 0.811 ± 0.058; adults, 0.810 ± 0.034). Furthermore, there was some evidence that survival was generally lower for all age classes during the low-density period than during the high-density period, possibly due to a chronic, persistent effect of organochlorine pesticides as the population recovered. Evidence for a density-dependent effect on survival was weak, but a negative effect of density on fidelity of juveniles (dispersing age class) during the recovery phase suggests density-dependent dispersal when the population was increasing. Our results show how population density can influence demographic parameters differently and how such influences can vary across phases of population growth.
authors: Scottish Raptor Study Group, 58 Meadowbank Road, Kirknewton, West Lothian, EH27 8BS, UK.
authors: George D
authors: GD
authors: Smith
authors: Oscar E
authors: OE
authors: Murillo-García
authors: Jeffrey A
authors: JA
authors: Hostetler
authors: Richard
authors: R
authors: Mearns
authors: Chris
authors: C
authors: Rollie
authors: Ian
authors: I
authors: Newton
authors: Michael J
authors: MJ
authors: McGrady
authors: Madan K
authors: MK
authors: Oli
mesh_terms: D000818:Animals; D003710:Demography; D004739:England; D046093:Falconiformes / Q000502:physiology*; D005260:Female; D008297:Male; D011156:Population Density; D011158:Population Growth; D012606:Scotland
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