PUBLISHER S NOTE 



provided biology with the first reasonably accurate figure for the 

 world population of any single and fairly numerous bird species. They 

 have, from their own notes and those of many amateur and professional 

 bird-watchers, produced interesting statistics of the total population 

 of the fulmar, the Manx shearwater, the puffin and many others. 

 Incidentally, such careful counts, site by site, reveal the continuous 

 change that is going on in sea-bird populations, often directly or 

 indirectly due to man's influence. 



The chapters on life-history are preceded by a general account of 

 social and sexual behaviour, which throws light upon the significance 

 of the prolonged and, to the observer, entertaining, mutual ceremonies 

 of these strictly monogamous birds, their pair-formation, their fidelity 

 to their mates, their nest-sites and their parental duties; at the same 

 time problems of instinct and learning ability are discussed. The life- 

 histories include much original field-work by the authors, who have 

 been responsible for several discoveries concerning the incubation and 

 fl.edging of a number of sea-birds. 



We read of the birds' ecology, their sharing of the wild frontiers 

 of the land where they nest, their niches in the economy of the ocean. 

 We learn of the contrasts between cliflT-dwelling and hole-nesting 

 species, of how the guillemot and razorbill chicks, exposed to many 

 dangers on the open rocks, hasten their feather-growth and depart to 

 the sea in two weeks, while the young puffins, safe in the darkness of 

 their burrows, delay their departue for seven weeks, and are finally 

 deserted by their parents ; we learn of the strange lives of the shear- 

 waters and small petrels which wander after the breeding season 

 between the North and South Atlantic Oceans, living in perpetual 

 summer — the Tristan shearwater "wintering" in our northern summer, 

 and the Manx shearwater enjoying its "winter" in the southern summer 

 off the coasts of South America. 



But we have said enough to indicate the richness of knowledge 

 brought together in this volume, which we confidently recommend 

 as indispensable to everyone interested in the birds of the sea. 



