Waterbirds in the Plum Island Sound Estuary, Massachusetts: Historical trends and current patterns

Because they are highly mobile and migratory, the presence and activity of birds in a region is a reflection of both local and global trends. We have been using historical records and current surveys to examine the status and trends over time of waterbirds in the Plum Island Estuary (PIE). Drivers include changes in land use, climate, and global shifts in avian populations and ranges. We have carried out surveys as part of the PIE LTER project and have also examined historical data sets and data from the United States Fish and Wildlife Service.  Some trends in the estuary are similar to regional trends: increases in mallards, Canada geese, ospreys, and willets. Regional declines in American black ducks and snowy egrets, are not reflected in counts at PIE. Numbers of saltmarsh sparrow, a species of conservation concern, also appear to be stable, however the future of this obligate salt marsh species is clouded by uncertainty about how marshes will respond to sea level rise.  Our current surveys are focused on examining the habitats and subregions of the estuary that are currently most important to waders and shorebirds.  Preliminary results suggest that feeding areas selected by shorebirds are relatively consistent and are associated with characteristics of the benthic substrate.  On the other hand, egrets and other waders are opportunistic in their preferred feeding areas since daily and lunar tidal cycles affect the availability of the nekton upon which they feed.  Ultimately we hope to gain insights into how sea level rise might affect bird use of the Plum Island Sound region.