Attachment

Download

From satellite tracking data, we recognised 5 major flight patterns in the annual cycles of 3 Chatham albatrosses (Thalassarche eremita) tracked in 1997 and 1998: foraging flights while the birds were breeding; eastward and westward migrations across the southern Pacific Ocean; northward migration along the South American coast; and localised foraging at low latitudes off the northwest coast of South America. We hypothesised that the 5 modes of flight indicated different biological activity. The associated speeds, point-to-point distances flown day-1, and other indices of activity were inferred from distances and times between satellite location records. Mean minimum point-to-point flight speeds were up to 85 km h-1 and were a function of the time interval for the measurement. Daily rates of change for latitude and longitude and the minimum daily distances travelled were calculated. These are the 1st measurements for this species of the sustained speed of flight point-to-point over varied time periods, and for short and long distances throughout the year. These data and the analytical techniques developed show what information can be obtained from a few individuals, and the confounding variables that result from the satellites’ orbits, and the transmitting characteristics of long-duration PTT experiments. The interrupted reception of transmitters through the intermittent satellite passes biases speed and other measurements and difficulties interpreting these data are discussed. The results provide a guide to the design of satellite transmitter experiments for long distance and duration studies with other oceanic species. They also contribute to an understanding of where this species obtains its food, and of its potential risk of interaction with fisheries.