There are at least twenty-eight types of gull species seen in North America. These birds are fairly well distributed throughout the continent along the coastlines and at sea. Although, gulls are referred to as seagulls on a daily basis by most people, they are referred to as "gulls" in the birding society.
Gulls are no doubt some of the hardest birds to easily identify. The plumage of the juveniles of different species takes from three to four years to achieve an adult plumage. Some of the gull types have a non-breeding and a breeding plumage that change throughout the seasons. To make this even more challenging, gulls cross-breed with other types of gulls, forming hybrids that reflect the looks and characteristics of each of the parent birds.
Originally, gulls were only scavengers of the waters on lakes, rivers or oceans on the continent. Today, these same birds compete with the crows in scavenging the city parks and food outlets. Gull species range in size from the small Little Gull with an approximate body length of 12 inches and a wingspan of 24 inches, to the large Great Black-backed Gull with an approximate body length of 30 inches and a wingspan in the mid-sixties inches.
Here is a list of Gulls seen in North America, native and vagrant birds included.