Postnatal dispersal of wandering albatrosses Diomedea exulans: implications for the conservation of the species

Abstract

dispersal of wandering albatrosses Diomedea exulans : implications for the conservation of the species. Á/ J. Avian Biol. 37: 23 Á/28.Many large marine vertebrates are today threatened by human activities and it is therefore crucial to obtain information on their distribution and behaviour at sea. In particular little is known about the time necessary for juveniles to acquire the foraging skills of adults. We tracked 13 juvenile wandering albatrosses Diomedea exulans by satellite telemetry during their first year at sea. They covered an average distance of 184 000 km during the first year and restricted their dispersal to the unproductive waters of the subtropical Indian Ocean and Tasman Sea. This region of low wind velocities does not overlap with the foraging areas used by adults. After an innate phase of rapid dispersal with a fixed flight direction, young birds progressively increased their daily flight distances and attained adult flight efficiency within their first six months at sea. The complete overlap of the juveniles' foraging ranges with major long-line fisheries in the subtropical waters constitutes a major threat that could jeopardize the long term recovery ability of populations of the endangered wandering albatross in the Indian Ocean.

Flexibility in otherwise consistent non-breeding movements of a long-distance migratory seabird, the long-tailed skua

“…This spatial memory may have its origin in explorative movements during early life (Pulido 2007, Guilford et al 2011, Senner et al 2015, which would enable longtailed skuas to respond to changes in the distribution of favourable areas relatively quickly, assuming that explorative movements allow for discovery of novel areas. Crucially, the genetic background, as well as the occurrence and extent of exploration behaviour in the first years of life and subsequent life stages, need to be demonstrated for the far majority of seabirds (but see Kooyman et al 1996, Weimerskirch et al 2006, Péron & Grémillet 2013, including longtailed skuas. …”

Stage-dependent distribution of the Critically Endangered Amsterdam albatross in relation to Economic Exclusive Zones

“…Our study shows that there are new concerns for the conservation of seabirds at sea, notably in the case of immature individuals. These birds may actually represent the most challenging category of the population to conserve adequately because of both their extremely large spatial distribution intersecting the highest number of countries' EEZs, and their inexperience in dealing with at-sea threats (Gales et al 1998, Weimerskirch et al 2006, Trebilco et al 2008. Conversely, movement metrics were never significantly different between sexes, which may limit the complexity of conservation measures for this species.…”

“…Our study provides (1) one of the first tracking surveys of an albatross species covering its entire life cycle (see also Weimerskirch et al 2014), and (2) the scientific basis for the implementation of conservation measures within EEZs. Similarly to the congeneric wandering albatross D. exulans, we expected the birds to show a wider distribution, and hence to visit more EEZs, with longer time at sea, especially outside of the breeding season and during the immature stages (Weimerskirch & Wilson 2000, Weimerskirch et al 1993, 2006.…”

“…Our survey aims to identify which countries share responsibility for the species' conservation at sea, where it is legally feasible to engage efforts. Little information was previously available on this species' distribution during breeding (Waugh & Weimerskirch 2003), and thanks to the tremendous development of telemetric approaches (Wilson & Vandenabeele 2012), we have been able to compile a unique data set of individual tracking records on all age-(juvenile, immature, adult) and breeding-related (incubation, brooding, chick-rearing, sabbatical, failed breeder) classes of the population, including prolonged phases the birds spend exclusively at sea (Weimerskirch & Wilson 2000, Weimerskirch et al 2006. Our study provides (1) one of the first tracking surveys of an albatross species covering its entire life cycle (see also Weimerskirch et al 2014), and (2) the scientific basis for the implementation of conservation measures within EEZs.…”

Ontogenetic changes in at-sea distributions of immature short-tailed albatrosses Phoebastria albatrus

“…Dispersal is characterized by direct movement to foraging grounds, suggesting genetic or cultural incies, both genetics and learning are likely to play an important role in migration and the development of habitat preferences. For example, some seabirds, fledge by themselves or in the company of other naïve individuals, and are thus initially reliant on innate compass directions and responses to environmental cues (Weimerskirch et al 2006, de Grissac et al 2016. Over time they then develop foraging stra tegies that are similar to adults (Riotte-Lambert & Weimerskirch 2013, de Grissac et al 2017.…”