It is an ornithopter modeled on the herring gull. This form has a troubled taxonomic history, summarised in the herring gull article. The call is a "laughing" cry similar to that of the herring gull, but deeper. The lesser black-backed gull is smaller than the European herring gull. These include cormorant, black-headed gull and herring gull. In 1964 on Little Sister Island only 41% of herring gull eggs hatched. It was later reclassified as a subspecies of the herring gull ("Larus argentatus"). This species also hybridizes regularly with the herring gull in Alaska. Among these species are the shearwater Cinderella, little shearwater and the herring gull. Three gull species also nest on Baffin Island&colon; glaucous gull, herring gull and ivory gull. As a direct result, European herring gull populations in Britain skyrocketed. Also, each European herring gull pair commonly rears three chicks per year. Besides being a competitor for nesting sites, the larger herring gull steals eggs and hatchlings. The European herring gull ("Larus argentatus") is a large gull, up to long. Year round residents include herring gull, greater black-backed gull, common tern and double-crested cormorant.