I have been invited to introduce the book arising out of the BOU Mascarene Island Expedition because this project took place during my term of office as President of the BOU. I am pleased to take advantage of this gesture.

The BOU has a long tradition of ornithological exploration. During the latter part of the last century many distinguished members made important collections in remote parts of the world, and The Ibis in consequence was full of long faunistic lists. Such ventures were privately financed and leisurely in tempo. From time to time, the BOU organized its own larger-scale expeditions, financed at least in part from its own funds, notable examples being the Jubilee Expedition to Dutch New Guinea (1909-11) and the Centenary Expeditions to Ascension Island (1957-9) and the Comoro Islands (1958). The Jubilee Expedition was over-ambitious and failed to reach its final destination, though doing useful work in an alternative location. Both the Centenary Expeditions of 1958/9, however, were highly successful, thanks to the care with which they were organized and to the skilled leadership of Dr Bernard Stonehouse in Ascension and of C. W. Benson in the Comoros. Previous expeditions had been chiefly concerned with collecting, at a time when museum collections were still far from complete. This was, however, a diminishing requirement; concern for the conservation of rare species was gaining momentum and studies of birds in the field had emerged as the primary interest among ornithologists. Although limited collecting was necessarily involved in the Com oros in order to fill important gaps in existing material, both Centenary Expeditions concentrated on ecological and behavioural studies.