Survival and population persistence in the critically endangered Tuamotu kingfisher |
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Authors: | Dylan C. Kesler Rebecca J. Laws Allison S. Cox Anne Gouni Joshua D. Stafford |
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Affiliation: | 1. Fisheries and Wildlife Sciences, University of Missouri, Columbia, 302 ABNR, MO 65211, USA;2. Société d'Ornithologie de Polynésie “Manu,” Taravao, Tahiti, French Polynesia;3. University of Illinois, Institute of Natural Resource Sustainability, Illinois Natural History Survey, Bellrose Waterfowl Research Center, P.O. Box 590, Havana, IL 62644, USA |
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Abstract: | A wide range of threats affect populations of Pacific island birds and conservationists have been challenged to identify factors upon which to focus management. The Tuamotu kingfisher (Todiramphus gambieri) is one of the most endangered vertebrate species in the world, yet little has been published about basic biology or causes of the population decline. We used 4 years of mark-resight and territory resource information to model survival in juvenile and adult Tuamotu kingfishers. Annual survival of adult males (ϕ = 0.77) was similar to congeneric species, whereas survival of adult females (ϕ = 0.40) and juveniles (ϕ = 0.12) was much lower. The best-supported survival model indicated adult female survival was positively related to territory size, whereas adult male survival was negatively related to atoll forest within territories. We used parameter estimates from survival models in a life-stage simulation analysis to evaluate the relative influence of vital rates and territory habitats on population processes. Results indicated that adult female and juvenile survival had the greatest impact on Tuamotu kingfisher populations, accounting for 58% and 32% of variation in the finite rate of population increase, respectively. Nocturnal predation by rats (Rattus spp.) on incubating kingfishers may explain the lower survival of females than males, whereas juvenile birds may be especially vulnerable to predation by cats (Felis catus). Thus, conservation management for Tuamotu kingfishers should include use of metal guards on cavity trees to protect nests and incubating females, and control predator access during fledging periods. © 2012 The Wildlife Society. |
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Keywords: | endangered French Polynesia island birds life-stage simulation population processes population projection matrix survival Todiramphus gambieri Tuamotu kingfisher |
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