Effects of habitat loss on shorebirds during the non-breeding season:: Current knowledge and suggestions for action

Many shorebirds are Nearctic-Neotropical migrants that move from their northern breeding grounds to wintering areas in Central and South America. Shorebirds differ from many other groups of avian migrants by their extremely long and demanding flights, gregariousness, restriction to limited numbers of sites, long lifespans, and low recruitment. Migration monitoring data suggest that population declines are occurring in shorebirds that breed in North America, and non-breeding habitat loss is thought to be a contributing factor. Considerable habitat loss and degradation from anthropogenic activities have influenced wetlands across the shorebird non-breeding range. If we wish to predict the consequences of habitat loss for shorebird populations, we must not only quantify changes in available habitat area, but also understand the role of density-dependence as populations pack into or expand from areas, as demonstrated for European shorebird population parameters. In contrast, little is known about the population or behavioral ecology of the wintering shorebirds south of the United States. We briefly review of the state of knowledge of the effects of habitat loss on shorebirds during the non-breeding season in the Neotropics, illustrated with several examples, to highlight the many unanswered questions. It is crucial to gain better understanding of population limiting factors in this region because shorebird populations are influenced by habitat alterations across the non-breeding range. The relative importance of non-breeding vs breeding season density-dependence remains to be assessed for most species.