Many birdwatchers may never have seen a skua; those who have will most probably have vivid memories of one or other species flying powerfully past a headland or twisting and diving in pursuit of its piratical intentions towards a food-laden seabird - or, perhaps more memorably still, of themselves taking evasive action from the power-diving irate skua whose territory they have unwisely invaded.The full classification of the skuas is still debated, but Dr. Furness of the Applied Ornithology Unit, Glasgow University, favours six species, of two genera, with five subspecies, based on current knowledge and his own long and dedicated field studies and research.All of the species treated comparatively under the following chapter Early history and classification, Distributions and populations, Migration patterns, Reversed sexual size dimorphism, Behaviour, Food and feeding, Kleptoparasitsm, Plumage polymorphism, Breeding systems and social organisation, Breeding - laying to hatching, Breeding - hatching to fledging, Populations dymanics, Pollutants, Skuas and agriculture, Skuas and conservation.The text is supported by 100 maps and diagrams, 30 photographs and 65 tables. In addition, John Busby contributes 35 evocative drawings which more than embellish this erudite and readable summary of an impressive and diverse group of birds.