Sex-specific foraging strategies throughout the breeding season in a tropical, sexually monomorphic small petrel

Causes and consequences of individual variability and specialization in foraging and migration strategies of seabirds

“…Social dominance and competitive exclusion are particularly prevalent in dimorphic species where one sex has an obvious physical advantage, but there is increasing evidence for sex differences in monomorphic species as well (Lewis et al 2002, Pinet et al 2012, Hedd et al 2014. A classic example of social dominance is where larger, male giant petrels Macronectes spp.…”

“…Males (which usually perform a greater role in nest defence) often forage more locally and visit the colony more frequently, whereas females often go on a pre-laying exodus, engaging in longer foraging trips in more productive waters to meet energetic or other nutritional requirements for the clutch (Lewis et al 2002, Yamamoto et al 2011, Hedd et al 2014, Quillfeldt et al 2014, Pistorius et al 2015. Indeed, changing energetic or nutritional requirements during the breeding cycle would explain why sex differences are apparent only at certain stages in mono morphic species such as Barau's petrel Pterodroma baraui (Pinet et al 2012) or why late-incubation trips by male southern rockhopper penguins are longer, as they do all the early chickguarding (Ludynia et al 2013). In theory, such differences seem less likely if the male courtship feeds the female, potentially contributing substantially to clutch formation as in terns, gulls and skuas (Becker & Ludwigs 2004), but this does not seem to be the case in the brown skua, as a higher proportion of females than males undertake a pre-laying exodus (Carneiro et al 2016).…”

“…Although the constraints for males and females may differ, individuals typically forage further from the colony and in more productive waters than in later stages (Phillips et al 2006, Paiva et al 2008, Pinet et al 2012, Hedd et al 2014. During incubation, most seabirds alternate incubation bouts, with one parent incubating the clutch while the other is at sea.…”

Sexual segregation in a wide-ranging marine predator is a consequence of habitat selection

“…However, while sexspecific habitat use has been widely documented in terrestrial species (Ruckstuhl & Neuhaus 2005), between-sex differences in habitat use in relation to dynamic oceanographic features have rarely been quantified (but see Pinet et al 2012). Moreover, in the marine environment, sexual segregation may occur in the vertical as well as horizontal dimension, especially in diving species (Kato et al 2000.…”

Year-round distribution and habitat preferences of the Bugio petrel

“…Nevertheless, these data allowed the designation of a Marine Important Bird Area (PTM16-Desertas) in 2008, which was presumed to cover some of the key areas used by breeding birds (Ramírez et al 2008). Previous studies of the movements of Pterodroma species clearly indicate that they disperse over large ocean areas, even during the breeding season (MacLeod et al 2008, Rayner et al 2008, Pinet et al 2012 and are highly migratory (Pinet et al 2011b, Rayner et al 2011. Given the lack of information on the location of core habitat for the Bugio petrels beyond the boundary of the ship surveys, including areas used during the nonbreeding period, the purpose of the present study was to analyse the at-sea distribution, movements and activity patterns of Bugio petrels tracked year-round.…”