Tracking Ocean Wanders (PDF, 5 MB) - BirdLife International

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12 Tracking ocean wanderers: the global distribution of albatrosses and petrels – Results the foraging strategy completely changes. They make short foraging trips lasting 1–5 days (average 2 days) and forage mainly over the Crozet shelf, the shelf break and the neighbouring oceanic waters. They mostly concentrate on Figure 3.2. Satellite/platform terminal transmitter (PTT) tracking locations submitted to the Global Procellariiform Tracking Database. Figure 3.3. Geolocator (GLS) tracking locations submitted to the Global Procellariiform Tracking Database. the shelf break, in sectors that are colony-specific. For Possession Island these sectors are mostly concentrated on the south-eastern shelf edge, at a distance of 20–50 km from the colonies. As soon as the chick is left alone on the ■ Amsterdam Albatross ■ Short-tailed Albatross ■ Antipodean Albatross ■ Shy Albatross ■ Black-browed Albatross ■ Sooty Albatross ■ Black-footed Albatross ■ Northern Giant-petrel ■ Buller’s Albatross ■ Southern Giant-petrel ■ Chatham Albatross ■ Northern Royal Albatross ■ Gibson’s Albatross ■ Southern Royal Albatross ■ Grey-headed Albatross ■ Tristan Albatross ■ Indian Yellow-nosed Albatross ■ Wandering Albatross ■ Laysan Albatross ■ White-chinned Petrel ■ Light-mantled Albatross ■ Black-browed Albatross ■ Grey-headed Albatross
Tracking ocean wanderers: the global distribution of albatrosses and petrels – Results Figure 3.4. Utilisation distribution maps for breeding Wandering Albatrosses tracked from Iles Crozet at different stages in the breeding cycle. A. incubating birds (n=38,011 hrs); B. chick rearing (n=10,859 hrs). (Unable to determine number of individuals of each category from dataset, so sample sizes are given in number of hours tracked.) nest, birds use a two-fold strategy, whereby they alternate long foraging trips in oceanic waters (similar to those of the incubation period) with a succession of short trips to the shelf edge and neighbouring oceanic waters (similar to the brooding period trips). Oceanic trips are mainly done to the north of the Crozet Islands, i.e. birds no longer go south to Antarctic waters. These important changes in foraging habitats and duration of trips observed at Crozet at different stages of the breeding season (see also Figures 3.13 and 3.14) have been found at other breeding sites, e.g. South Georgia, Marion Island and also Kerguelen Island. Henri Weimerskirch Tristan Albatross Diomedea dabbenena – Gough The utilisation distribution maps for the Tristan Albatross reveal substantial differences between the three major stages of the breeding cycle. During incubation most foraging is concentrated around Gough Island from 20°W to 0° of longitude and between 35–50°S, although some individuals also made trips to western areas of the South Atlantic moving as far as 50°W (Figure 3.5A). Foraging trips during incubation averaged 10 days (range 6–22 days) and with an average foraging range of 940 km. During the brood/guard stage foraging trips averaged 2 days (range 0.5–4 days) and are centred on Gough (Figure 3.5B), with an average range of 380 km. The sudden change from trips of long duration during incubation to short trips in the brood/guard stage is expected, as breeding adults are constrained to frequently feed small chicks at this time (Weimerskirch et al. 1993, Prince et al. 1998). During the post-guard stage the foraging distribution of breeding adults ranges across the South Atlantic from 50°W to 10°E and between latitudes 30–45°S. Trips during the post-guard stage averaged 5 days in duration (range 1 to 21 days) and varied greatly in range, with the maximum distance of trips varying from 110 to 3,500 km. The distribution of foraging locations indicates no clear pattern in relation to bathymetric features with most foraging locations concentrated over pelagic waters (>3,000 m depth) and within the sub-tropical zone and sub-tropical convergence zones. The distribution of the Tristan Albatross mainly between 30–45°S suggests that the species is at considerable risk from longline mortality as most pelagic fishing effort in the South Atlantic occurs within these latitudes (Tuck et al. 2003). However, variation between different stages of the breeding cycle and spatial variation in pelagic fishing effort over the year means that numbers of 13
Page 1 and 2: TRACKING OCEAN WANDERERS The global
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neither assessed albatross mortalit
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e examined. Several of the New Zeal
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6.2.2 Interactions with fisheries a
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76 Table 1 ... continued. Breeding
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w. John Croxall, Richard Phillips,
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Species Colony Incubation Chick-rea
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Species Colony Incubation Chick-rea
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6.1 Example of data provider profil
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3) Request Statement a) Data Specif
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At the last stage before final proo
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GEORGES, J. Y., GUINET, C., JOUVENT
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SULLIVAN, B. J., REID, T. A., BUGON
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conspicillata 82 parkinsoni 82 west
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