Environmentally driven sexual segregation in a marine top predator

Abstract

Sexual segregation in foraging occurs in many animal species, resulting in the partitioning of resources and reduction of competition between males and females, yet the patterns and drivers of such segregation are still poorly understood. We studied the foraging movements (GPS-tracking), habitat use (habitat modelling) and trophic ecology (stable isotope analysis) of female and male Cory’s shearwaters Calonectris borealis during the mid chick-rearing period of six consecutive breeding seasons (2010–2015). We found a clear sexual segregation in foraging in years of greater environmental stochasticity, likely years of lower food availability. When food became scarce, females undertook much longer foraging trips, exploited more homogeneous water masses, had a larger isotopic niche, fed on lower trophic level prey and exhibited a lower body condition, when compared to males. Sexual competition for trophic resources may be stronger when environmental conditions are poor. A greater foraging success of one sex may result in differential body condition of pair mates when enduring parental effort, and ultimately, in an increased probability of breeding failure.

Flying south: Foraging locations of the Hutton's shearwater (Puffinus huttoni) revealed by Time‐Depth Recorders and GPS tracking

“…Such “bimodal” patterns of distribution at sea have been found in Cory's shearwater Calonectris diomedea , and sooty shearwater Puffinus griseus (Baduini & Hyrenbach, ; Paiva et al, ; Shaffer et al, ). Patterns of foraging can also change due to seasonal changes in environmental conditions (e.g., chlorophyll a levels), increased levels of competition, stochastic events, and greater fisheries pressures (Jodice & Suryan, ; Richard et al, ; Paiva et al, ).…”

“…However, variation in productivity and foraging conditions can affect the foraging behavior of a species, whereby some individuals either forage at great distances from the colony or remain close to the nesting site (Jaeger et al, 2014;Paiva, Pereira, Ceia, & Ramos, 2017). Such "bimodal" patterns of distribution at sea have been found in Cory's shearwater Calonectris diomedea, and sooty shearwater Puffinus griseus (Baduini & Hyrenbach, 2003;Paiva et al, 2017;Shaffer et al, 2009). Patterns of foraging can also change due to seasonal changes in environmental conditions (e.g., chlorophyll a levels), increased levels of competition, stochastic events, and greater fisheries pressures (Jodice & Suryan, 2010;Richard et al, 2015;Paiva et al, 2017).…”

Does sexual segregation occur during the nonbreeding period? A comparative analysis in spatial and feeding ecology of three Calonectris shearwaters

“…Calonectris shearwaters are wide-ranging species, performing long-distance migrations across ocean basins after the breeding period and spreading over diverse nonbreeding areas (González-Solís, Croxall, Oro, & Ruiz, 2007;Thibault, Bretagnol, & Rabouam, 1997), thus exposing the individuals to variable environments that can lead to SS in foraging strategies in different ways (Åkesson & Weimerskirch, 2014;Bearhop et al, 2006;Ceia et al, 2012;Phillips, Bearhop, McGill, & Dawson, 2009; Figure 1). These species are relatively well-studied during the breeding period, and many studies have been done with respect to their SS (Alonso et al, 2014;Werner, Paiva, & Ramos, 2014;Cianchetti-Benedetti, Catoni, Kato, Massa, & Quillfeldt, 2017;Matsumoto, Yamamoto, Yamamoto, Zavalaga, & Yoda, 2017;Navarro, Kaliontzopoulou, & González-Solís, 2009;Paiva, Pereira, Ceia, & Ramos, 2017;Ramos, Granadeiro, Phillips, & Catry, 2009a;Ramos, González-Solís, et al, 2009b). In these species, SS in foraging behavior and feeding ecology may be shaped by annual and seasonal prey availability (Paiva et al, 2017), differences in reproduction duties over the breeding period (Werner et al, 2014;Ramos, González-Solís, et al, 2009b), and/or could be related to SSD between sexes (Alonso et al, 2014;Cianchetti-Benedetti et al, 2017).…”

“…These species are relatively well-studied during the breeding period, and many studies have been done with respect to their SS (Alonso et al, 2014;Werner, Paiva, & Ramos, 2014;Cianchetti-Benedetti, Catoni, Kato, Massa, & Quillfeldt, 2017;Matsumoto, Yamamoto, Yamamoto, Zavalaga, & Yoda, 2017;Navarro, Kaliontzopoulou, & González-Solís, 2009;Paiva, Pereira, Ceia, & Ramos, 2017;Ramos, Granadeiro, Phillips, & Catry, 2009a;Ramos, González-Solís, et al, 2009b). In these species, SS in foraging behavior and feeding ecology may be shaped by annual and seasonal prey availability (Paiva et al, 2017), differences in reproduction duties over the breeding period (Werner et al, 2014;Ramos, González-Solís, et al, 2009b), and/or could be related to SSD between sexes (Alonso et al, 2014;Cianchetti-Benedetti et al, 2017). However, while many of these studies did find evidence of sexual differences in foraging and feeding ecology during the breeding period (Alonso et al, 2014;Werner et al, 2014;Cianchetti-Benedetti et al, 2017;Matsumoto et al, 2017;Paiva et al, 2017;Ramos, González-Solís, et al, 2009b), many others did not find any clear difference (Navarro, González-Solís, & Viscor, 2007;Navarro et al, 2009;Ramos, Granadeiro, et al, 2009a).…”

“…In these species, SS in foraging behavior and feeding ecology may be shaped by annual and seasonal prey availability (Paiva et al, 2017), differences in reproduction duties over the breeding period (Werner et al, 2014;Ramos, González-Solís, et al, 2009b), and/or could be related to SSD between sexes (Alonso et al, 2014;Cianchetti-Benedetti et al, 2017). However, while many of these studies did find evidence of sexual differences in foraging and feeding ecology during the breeding period (Alonso et al, 2014;Werner et al, 2014;Cianchetti-Benedetti et al, 2017;Matsumoto et al, 2017;Paiva et al, 2017;Ramos, González-Solís, et al, 2009b), many others did not find any clear difference (Navarro, González-Solís, & Viscor, 2007;Navarro et al, 2009;Ramos, Granadeiro, et al, 2009a). Nonetheless, the degree to which SS in foraging performance continues out of the breeding period is still poorly known in these species (Müller et al, 2014).…”