Summary

Description

Surveys were conducted to relate waterbird densities to habitat type and season. These consisted of transects that were repeated throughout the year and onetime shoreline surveys of the entire western half of PWS in summer. In addition, blacklegged kittiwake Rissa tridactyla colonies were censused. Our data indicated that results from multispecies summer surveys can be highly variable, however, gross trends were observed. More birds were along shorelines than in open water throughout PWS.in all seasons. There were more birds in summer than winter, but there were more species in winter. We found local differences in shoreline densities and diversity between study areas. There were also differences between transects with high wave exposure and transects that were protected. In summer more birds were in exposed transects than protected transects. In winter the opposite was true. Two factors caused much of the difference in bird densities. The presence of blacklegged kittiwakes at colonies caused a tremendous increase in the number of birds near colony sites during summer. In winter, waterfowl use of large grasscovered tidal flats caused an increase in the numbers of birds in those areas.