SATELLITE TELEMETRY

OBJECTIVES

King Eiders spend much of their annual cycle at sea where they are very hard to observe. Unlike other birds of the arctic they do not migrate into much warmer climates during winter, but remain close to the pack ice even in winter. In order to track the movements of King Eiders at sea, we used implantable satellite transmitters. The transmitters are implanted into the body cavity of the ducks and have a battery life of around 13 months. During this time the position of the duck can be determined from the signal its transmitter sends to the satellites.

The main goal of this study is to determine where King Eiders spend the 10 months between breeding seasons. So far it is known that males leave the breeding area as soon as females start incubating the eggs. The males then gather at sea to molt their feathers. The females follow at a later time,after they have either raised their young or lost their nest. To date it is not fully understood where juveniles spend their first two years, and whether males and females use the same or different areas to molt.

In winter life at sea is very rough. Days are short, and forming pack ice may prevent access to good feeding areas. With the satellite telemetry we will attempt to track the movements of King Eider in winter, and try to determine whether certain weather patterns or other factors trigger winter movements by King Eiders.

Tracking birds into the next breeding season will also enable us to test whether King Eiders return to the same breeding areas every year. So far we found that all females return to the same breeding location every year, whereas males from Alaska might fly to Siberia or Canada in the next summer.

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