Original Paper

Biodiversity and Conservation

, Volume 22, Issue 1, pp 63-75

First online:

Long-term decline of a winter-resident bird community in Puerto Rico

  • John FaaborgAffiliated withDivision of Biological Sciences, University of Missouri Email author 
  • , Wayne J. ArendtAffiliated withInternational Institute of Tropical Forestry, US Forest Service, Sabana Field Research Station
  • , Judith D. TomsAffiliated withDivision of Biological Sciences, University of MissouriEco-Logic Consulting
  • , Katie M. DuggerAffiliated withDepartment of Fisheries and Wildlife, Oregon State UniversityU.S. Geological Survey, Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries and Wildlife, Oregon State University
  • , W. Andrew CoxAffiliated withDepartment of Fisheries and Wildlife Sciences, University of Missouri
  • , Miguel Canals MoraAffiliated withDRNA-Bosque de Guánica

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Despite concern expressed two decades ago, there has been little recent discussion about continuing declines of migrant bird populations. Monitoring efforts have been focused almost exclusively on the breeding grounds. We describe the long-term decline of a winter-resident bird population in Guánica Commonwealth Forest, Puerto Rico, one of the last remaining tracts of high-quality tropical dry forests in the Caribbean. The winter bird community has exhibited dramatic declines, with constant-effort mist netting now capturing about one-third as many birds as it did 20 years ago. Population estimates for the three most common species have declined dramatically, even though survival rates have remained constant, and other species are now virtually absent from a site where they once were fairly common. Although explanations for these declines are speculative, particularly because they involve multiple species, we argue that the strength and duration of these declines in well-preserved dry forest within a biosphere reserve should stimulate renewed discussion of migrant population trends and comparison with other recent monitoring activities.


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