Author: Stephen Brown (SB), Manomet Center for Conservation Science, Manomet, MA.
Additional data on population regulation are needed, particularly the effects of predators on nesting success rates and fledging rates of chicks, and the impacts of disturbance on nesting success. Because nesting success varies dramatically among years, we need to determine whether lifetime success of individual breeding pairs occurs in a small number of relatively high success years. We also need additional work on recruitment rates into the population of the fledglings that do survive, whether there are dominance systems like in the European Oystercatcher, and whether there are density-dependent effects on the breeding grounds. In addition, further research is needed on the effectiveness of management to increase nesting success using techniques like electric fences, predator exclosures, raising nest elevations, and artificial incubation.
Current and future impacts of climate change are expected to be significant, but the magnitudes of specific effects are poorly understood. Effects of rising sea levels and changes in storm frequency and intensity on breeding habitat, nesting success, and predator populations should be investigated. Large storms apparently depress predator populations for a few years, but predators eventually recover and cause significant depression of annual reproduction. It would be valuable to use remote sensing to determine whether nesting habitat has declined since 1980. Also, if birds are moving into salt marshes, nests there may be relatively more vulnerable, so there is a need to monitor the proportion of nesting attempts in various habitats.
Studies in Virginia, South Carolina, Georgia, and North Carolina have documented prey species composition, but more information is needed on the distribution and quality of the forage base for American Oystercatchers across much of the range of the species. There is little published information on the availability, species composition, and abundance of prey species in the Northeast and in the Gulf of Mexico. More research is needed on metabolism, and energetic requirements of AMOY throughout the year so that carrying capacities can be calculated based on available prey. Applied research on the effectiveness of efforts to create and manage nesting and foraging habitat are needed due to the ongoing losses of both types of habitat for this species.
Studies currently underway using marked birds, coordinated by the Working Group, are expected to provide critical information, including linkages of breeding and wintering sites, rates of adult and juvenile survival, and relative importance of migration and wintering areas. These efforts should be sustained through a long term coordinated monitoring program. Long term range-wide monitoring is also needed to measure population responses to ongoing intensive management efforts.
Significant gaps remain in our understanding of the life history, migratory strategy, population size and trend, and conservation threats for the species in its range outside of eastern North America, which should be addressed to help support conservation efforts range-wide (Clay et al. 2010).