Tracking reveals behavioural coordination driven by environmental constraints in the Black‐vented Shearwater Puffinus opisthomelas

Abstract

During the breeding season, seabird foraging trips are constrained by nest attendance schedule and are necessarily colony centred. Oceanographic cues play a major role in the choice of foraging areas to minimize the time spent away from the nest. Here, we analysed the foraging tracks of Black‐vented Shearwaters Puffinus opisthomelas during the incubation and chick‐rearing periods of 2016 and 2017 at Isla Natividad (Mexico). We applied expectation‐maximization binary clustering to track data to clusterize different behaviour patterns during foraging flights. We then applied binary generalized linear mixed models to characterize of foraging areas based on of environmental variables. We finally used kernel estimation techniques to describe main foraging areas. In 2016, breeding shearwaters used two core areas for foraging and resting on the water; the core area delineated by males was located northward from the colony in the Vizcaino Bay and the core area for females was located southward from the colony at the entrance of San Ignacio Lagoon. In 2017, males and females used the same areas with no evident segregation. Our study provided the first information on Black‐vented Shearwater foraging areas during the breeding season and indicated that sexual segregation within coastal waters off the central Baja California Peninsula might be a foraging strategy during years of warmer ocean, likely less productive regimes. Factors including ocean‐climate‐mediated sexual segregation at sea, leading to interannual variation in foraging areas, should be considered when evaluating management actions intended to protect critical foraging habitats for Black‐vented Shearwaters.

Sexual segregation in the foraging behaviour of a slightly dimorphic seabird: Influence of the environment and fishery activity

“…Instead, previous findings suggest that in slightly dimorphic species, sexual differences in foraging strategies are driven by the interaction at different extent among SSD, habitat selection, and environmental conditions (Cleasby et al, 2015;Paiva et al, 2017;Soldatini et al, 2019). In the marine environment, feeding resources are patchily distributed, but they are often predictable at large spatial scales (Stewart et al, 2000).…”

Mercury exposure in relation to foraging ecology and its impact on the oxidative status of an endangered seabird

“…Considering that turnover time in plasma and cellular component of blood vary from about 3 days to about 30 days, respectively (Hobson and Clark, 1993), we can assume that isotopes and Hg concentrations obtained from erythrocytes are representative of the breeding period and can be associated to the distribution range. Black-vented shearwater core foraging areas lie within the California Current System (Soldatini et al, 2019). Breeding period northern tracks evidence foraging areas in the Vizcaino Bay and along the continental slope while southern tracks are mainly along the continental slope.…”

Carry‐over effects of environmental stochasticity of the California Current on body condition and wing length of breeding Black‐vented Shearwaters (Puffinus opisthomelas)

“…The variability in biometrics observed during this period, together with the sexual segregation observed at the same time (Soldatini et al . 2019), reflect individuals’ efforts to cope with environmental fluctuations that induce resource scarcity. This flexibility may be increasingly important in coping with more frequent unfavourable warmer events such as El Niño and Warm Blob.…”