It is the time for oceanic seabirds: Tracking year‐round distribution of gadfly petrels across the Atlantic Ocean

Abstract

Aim: Anthropogenic activities alter and constrain the structure of marine ecosystems with implications for wide-ranging marine vertebrates. In spite of the environmental importance of vast oceanic ecosystems, most conservation efforts mainly focus on neritic areas. To identify relevant oceanic areas for conservation, we assessed the year-round spatial distribution and spatio-temporal overlap of eight truly oceanic seabird species of gadfly petrels (Pterodroma spp.) inhabiting the Atlantic Ocean. Location: Atlantic Ocean.Methods: Using tracking data (mostly from geolocators), we examined year-round distributions, the timing of life-cycle events, and marine habitat overlap of eight gadfly petrel species that breed in the Atlantic Ocean. Results:We compiled 125 year-round tracks. Movement strategies ranged from nonmigratory to long-distance migrant species and from species sharing a common nonbreeding area to species dispersing among multiple non-breeding sites. Gadfly petrels occurred throughout the Atlantic Ocean but tended to concentrate in subtropical regions. During the boreal summer, up to three species overlapped spatio-temporally over a large area around the Azores archipelago. During the austral summer, up to four species coincided in a core area in subtropical waters around Cape Verde, and three species shared habitat over two distinct areas off Brazil. The petrels used many | 795 RAMOS et Al.

Gadfly petrels use knowledge of the windscape, not memorized foraging patches, to optimize foraging trips on ocean-wide scales

“…Hence, to capitalize net energy gain, Desertas petrels seemed to rely on a foraging strategy based on covering large distances to increase the probability of encountering foraging opportunities along the route rather than consistently targeting known foraging areas [8,46]. Our results corroborate and build mechanistically upon the findings of previous studies, in which breeding gadfly petrels were found to have a similar foraging strategy, with long foraging trips [4][5][6][7] characterized by low foraging site consistency [6], and long periods of direct flight [4,7], and in which birds travelling for longer distances had higher mass gains [6].…”

“…Optimal foraging theory predicts that animals looking for food adopt mechanisms to maximize their energy acquisition per unit time and minimize their energy loss [1][2][3]. The constraints faced by breeding oceanic seabirds-patchily distributed resources and having to return to their colony to alternate incubation shifts with the partner-result in sometimes spectacular foraging trips, many thousands of kilometres from the colony [4][5][6][7]. Seabirds thus have morphology and flight behaviour adapted to glean energy for these long commutes from the wind.…”

“…As predicted by aerodynamic theory-and as suggested by their genus name (from the Greek words 'Pteron', wing, and 'dromos', run)-the high aspect ratio per wing loading (the highest of all seabirds) makes them especially anatomically adapted for efficient flight: a fast, gliding flight with low profile drag [20]. Gadfly petrels are highly mobile, capable of undertaking exceptionally long foraging trips [4][5][6][7] by spending a large proportion of time in direct flight, actively looking for prey [4,7]. For example, Murphy's petrels (Pterodroma ultima) tracked from Henderson Island did not consistently target specific areas and foraged both during directed movement and area restricted search [6], and the higher mass gains were associated with the most wide-ranging trips [6].…”

Spatial ecology, phenological variability and moulting patterns of the Endangered Atlantic petrel Pterodroma incerta

“…Most knowledge of its distribution at sea comes from shipbased sightings (Enticott 1991, Orgeira 2001. More recently, its general phenology and distribution were summarized together with other gadfly petrels species using tracking data (Ramos et al 2017). However, Ramos et al (2017) did not include detailed descriptions on its phenology and spatial ecology, the factors influencing migration schedules within the population or other important aspects of its at-sea ecology, such as habitat preferences, at-sea activity patterns and moulting strategies.…”

Abundance and species diversity hotspots of tracked marine predators across the North American Arctic

“…Given the logistical challenges of observing animals within the dynamic nature of polar environments, the application of animal telemetry devices has revolutionized our understanding of the movement ecology of marine species (Hussey et al, 2015). Telemetry data have provided novel insights into complex, previously unknown behaviours, including predator-prey interactions (Breed et al, 2017), fishing fleet interactions with fishes and seabirds (Queiroz et al, 2016;Rolland, Barbraud, & Weimerskirch, 2008;Tuck, Polacheck, Croxall, & Weimerskirch, 2001), environmental drivers of habitat use (Amélineau et al, 2018;Block et al, 2011;Raymond et al, 2015), species diversity hotspots (Grecian et al, 2016) and identifying critical conservation areas (Dias et al, 2017;Lascelles et al, 2016;Ramos et al, 2017). Traditionally, telemetry studies on Arctic marine predators have focused on single or a few species.…”