A pair of laughing gulls court in Virginia before the breeding season. Photo by Bart Paxton.

In one of the most dramatic responses to sea-level rise to date, laughing gulls within a historic stronghold along the Lower Delmarva Peninsula have collapsed in less than a decade. A recent survey conducted by the Center for Conservation Biology has revealed that the population declined from more than 25,000 to less than 4,400 breeding pairs between 2003 and 2013.

Stable for decades, the breeding population began to experience notable problems in the early 2000s when significant tidal events repeatedly washed out eggs and nests. Since that time, tidal disturbance appears to have pushed the population beyond a tipping point. Because the marsh islands used for nesting have little topographic relief, nearly the entire system was impacted simultaneously and the space used for nesting declined by more than 85%. Now, historic landmarks such as Gull Marsh and Egg Island named for the breeding birds no longer support them.

A comparison of laughing gull nesting colonies along the Lower Delmarva Peninsula in Virginia. Many colonies on marsh islands have fallen to sea-level rise between 2003 and 2013. Data from The Center for Conserv

Unlike herring and great black-backed gulls that have expanded their breeding range into the mid-Atlantic region over the past half century, laughing gulls have bred along the coast throughout recorded history. Breeding birds feed on a wide variety of prey but consume a large number of insects, many of which are agricultural pests. The species migrates to winter grounds in Central America, returning in April and May to historic breeding areas. For millions of Americans living along the outer coast, the raucous call of the laughing gull is one of the most familiar sounds of spring.

Historically, laughing gulls have been the most numerous seabird nesting within the mid-Atlantic region. The Center for Conservation Biology along with agency and nonprofit partners has surveyed the population periodically since the early 1980s.

Written by
Bryan Watts | bdwatt@wm.edu | (757) 221-2247
November 18, 2013