Global

Information organized taxonomically by family based on the latest official guidelines, with detailed descriptions for each, worldwide distribution maps for every family, and carefully selected profiles of 500 representative species. By Alderfer. Read more

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 distri Read more