Geolocation (Global Location Sensing or GLS logging) using archival light-recording tags offers considerable potential for tracking animal movements, yet few studies of flying seabirds have exploited this technology. Our study evaluated its effectiveness for determining foraging ranges of black-browed albatrosses Thalassarche melanophrys fitted simultaneously with GLS loggers and satellite-transmitters (Platform Terminal Transmitters, PTTs). After some preliminary validation, the position of an albatross could be determined by geolocation with a mean error ± SD of 186 ± 114 km (SDs of 1.66°and 1.82°of latitude and longitude, respectively). Errors from identical static loggers were lower (mean ± SD of 85 ± 47 km, with overall SDs of 0.61°and 0.99°of latitude and longitude, respectively) and less variable, with the difference attributable to variation in sensor orientation, intermittent shading by plumage, and the difficulty of correcting for extensive, potentially non-linear movements of flying birds. Iterative smoothing reduced both the mean error and the inflation of kernel ranges derived from GLS data, but over-smoothing contracted the extremes of the range. This reduced the overlap with radial cores apparent in the control data, and should be avoided for multinuclear GLS fix distributions. The accuracy of GLS tags is more than adequate for tracking migration and breeding-season foraging ranges of pelagic species, and for identifying broad-scale habitat preferences, overlap and potential conflict with commercial fisheries.

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The movements of two wandering albatrosses, one of each sex, breeding at South Georgia, were tracked using satellite telemetry, particularly to assess whether such birds could be at risk from longline fishing operations in the subtropics. Full details of the performance (number and quality of uplinks) of the Toyocom transmitters are provided, together with data on flight speeds and night and daytime travel by the albatrosses.The female, tracked for seventeen days-covering three foraging trips totalling 13951 km -had a much more northerly distribution than the male, which made two trips to sea during the same period and travelled aminimum distanceof 9280km. On one trip the female frequented the area off Brazil known to beused for longlinefisheries. The distributional differences between the sexes support earlier suggestions, based on at-sea observations, that the observed high mortality rates of South Georgian females could be due to a greater likelihood of incidental mortality in longline fishing. These results also show that the presence of females off Brazil can include birds still rearing chicks, rather than simply representing post-breeding dispersal.

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Abstr.~Let To investigate the role of sea ice cover on penguin populations we used principal component analysis to compare population variables of Ad6lie (Pygo:;celis adeliae) and chinstrap (Pygoscelis antarctica) penguins breeding on Signy Island, South Orkney Islands with local (from direct observations) and regiona{ (from remote sensing data) sea ice variables. Throughout the study period, the Ad61ie penguin population size remained stable, whereas that of chinstrap penguins decreased slightly. For neither species were there significant relationships between population size a:ld breeding success, except for an apparent inverse density-dependent relationship between the number of Ad61ie breeding pairs and the number of eggs hatching. For both species, no general relationship was found between either population size or breeding success and the local sea ice conditions. However, the regional sea ice extent at a particular time prior to the start c,r the breeding season was related to the number of bircs that arrived to breed. For both species, this period occurred before the sea ice reached its maximum extent and was slightly earlier for Ad61ie than for chinst:ap penguins. These results suggest that sea ice conditions outside the breeding season may play an important role in penguin population processes.

During 4- to 8-day periods at sea, half of 2595 dives of three king penguins were more than 50 meters and two dives exceeded 240 meters. The at-sea metabolic rate, estimated from the turnover of tritiated water, was 2.8 times the standard metabolic rate and requires about 2.5 kilograms of squid per day. Ten percent or less of the dives may result in prey capture.