Temperature Regulation in the Red-Tailed Tropic Bird and the Red-Footed Booby

Abstract

This paper represents part of a study on the thermoregulatory responses of nesting sea birds to natural environmental conditions. The investigations were conducted on Midway Island. Our previous publications (Howell and Bartholomew, 1961a, 1961b) have dealt with Laysan and Black-footed albatrosses (Diomedea immutabilis and D. nigripes), Bonin Island Petrels (Pterodroma hypoleuca), and Wedge-tailed and Christmas Island shearwaters (Pufinus pacificus and P. nativitatis). Bailey (1956) gives a useful account of the natural history of these and other species found on Midway. In the course of visits to Midway Island in June and July, 1959 and 1960, we were able to obtain data on thermoregulation in the Red-tailed Tropic Bird (Phaethon rubricauda) and the Red-footed Booby (Sula sula). Aside from the work of Probine and Wodzicki (1955) on the Gannet (Sula bassana) and that of Bartholomew, Dawson, and O'Neill (1953) and Bartholomew and Dawson (1954) on pelicans (Pelecanus), we know of no quantitative studies on thermoregulation in pelecaniform birds.