Maximum diving depths for feeding attained by Bulwer's petrels (Bulweria bulwerii) during the incubation period

All 20 of the Bulwer's petrels Bulweria bulwerii of Selvagem Grande (30 deg rees 09'N, 15 degrees 52'W) equipped with maximum depth gauges had dived du ring the feeding trips performed during the incubation period, the mean max imum depth being 2.4 +/- 1.0 m (range: 1.0-5.3 m). The depth reached showed no correlation with the breeding experience of the birds: with the length of their trip or with their body size and there were no differences between males and females. Thus, the Bulwer's petrel are among the numerous Procel larii-formes which perform regular but comparatively shallow dives, unlike shearwaters (Puffinus) and diving petrels (Pelecanoides) which can reach de pths of several tens of metres.