With more than 50 gull species in the world, this family of seabirds poses some of the greatest field identification challenges of any bird group: age-related plumage changes, extensive variations within species, frequent hybridization, and complex distribution. takes on these challenges and is the first book to provide a comprehensive look at these birds. Concise text emphasizes field identification, with in-depth discussion of variations as well as coverage of habitat, status, and distribution. Abundant photographs highlight identification criteria and, crucially, factor in age and subspecific field separation. Informative species accounts are accompanied by detailed color range maps. is the most authoritative photographic guide to this remarkable bird family.