Data from: The diet of a nocturnal pelagic predator, the Bulwer’s petrel, across the lunar cycle

The lunar cycle is believed to strongly influence the vertical
distribution of many oceanic taxa, with implications for the foraging
behaviour of nocturnal marine predators. Most studies to date testing
lunar effects on foraging have focused on predator activity at-sea, with
some birds and marine mammals demonstrating contrasting behavioural
patterns, depending on the lunar-phase. However, to date no study has
focused on how the lunar cycle might actually affect predator-prey
interactions in the upper layers of the ocean. Here, we tested whether the
diet of the predominantly nocturnal pelagic predator, the Bulwer’s petrel
(Bulweria bulwerii) would change throughout the lunar cycle, using
molecular analysis to augment detection and taxonomic resolution of prey
collected from stomach-contents. We found no evidence of dietary shifts in
species composition or diversity, with Bulwer’s petrel always consuming a
wide range of mesopelagic species. Other co-variables potentially
affecting light availability at-sea, such as percentage of cloud cover,
did not confound our results. Moreover, many of the species found are
thought not to reach the sea-surface. Our findings reveal that nocturnal
predators are probably more specialized than previously assumed,
irrespective of ambient-light, but also reveal deficiencies in our current
understanding of species vertical distribution and predation-dynamics
at-sea.