Feeding competition between laughing gulls and herring gulls at a sanitary landfill.

Laughing gulls Larus atricilla ate food at the dump or carried away items to eat elsewhere. Whenever herring gulls L. argentatus were present, laughing gulls could not land on the dump, were forced to move from good feeding areas once they did land, and lost food to herring gull pirates both on the dump and while carrying food away. Direct competition from herring gulls has prevented laughing gulls from greater exploitation of dumps in New Jersey in the past. Recent changes in the operations of dumps have reduced interspecific competition by providing a situation in which laughing gulls can effectively dip for food and herring gulls are prevented from feeding. Use of dumps by laughing gulls has thus increased in New Jersey. -from Author