Skuas are a wide-ranging group of seabirds; some are found as far south as the Antarctic and others in the Arctic regions of the world. They are one of the most challenging groups of birds to identify because of variation in plumage according to the age of a given bird and conditions for identifying them. This book-the first complete guide to the skuas of the world-was designed to enable species identification and correct aging of these birds.

The gulls are a large family of seabirds, familiar and distinctive as a group, but one of the most challenging to separate at the species level, especially in their various stages of immature plumage. This guide offers the most comprehensive treatment ever published on the gulls of North America, Europe, and Asia. Klaus Malling Olsen and Hans Larsson treat a total of forty-three species--each depicted in considerable detail, with a full description of every plumage and racial variation. The text is complemented not only by superb color paintings by Larsson, but also by 800 color photographs. Gulls explore a variety of habitats, consume a wide range of food, and are often extremely abundant. They are also great wanderers, with several American species often appearing in Western Europe and vice versa. As well as identification criteria, this book includes an up-to-date assessment of the range and status of every species, together with information on patterns on vagrancy. This important guide is published at a critical time in the development of gull taxonomy. The large white-headed gulls found in North America, Europe, and Asia comprise a superspecies complex, with the precise relationships between various components still under considerable debate. A thorough illustrative and textual treatment of the group is needed, and this book provides the most recent and complete overview. This is the essential reference to a fascinating and endlessly challenging group of birds.