Satellite Tracking of Sea Eagles

Following the use of GPS satellite transmitters on Scottish golden eagles and the tracking, sadly brief, of a young white-tailed eagle in Ireland in 2007, Roy Dennis was asked to organise GPS satellite transmitters for the Mull Eagle Watch. Two radios were purchased by the Mull Eagle Watch and these were fitted to the two chicks at the Loch Frisa hide nest on Forestry Commission land. The tagging visit was organised by Dave Sexton, the RSPB's Mull Officer, and the project is a community project.

In June 2008, Roy Dennis carried out the fitting of Microwave Telemetry GPS transmitters to two chicks at Loch Frisa on the island of Mull, for the Mull Eagle Watch. Using high quality GPS data collected at hourly intervals it is hoped to study how the young birds use their parents' home-range and then to follow their movements. Where will they go? How far will they travel? How long will they stay together? How often will they return home? If they get through their first winter where will each of them summer, and if they and their radios survive for three years where will each of them start to settle down at a breeding site. This the first time GPS radio transmitters have been used to track sea eagles in Scotland and will add much interest to the visual observations from the Loch Frisa Hide. The transmitters being used are 70 gram Argos GPS solar transmitter manufactured by Microwave Telemetry in the United States. They have a three season variable program which can collect hourly data from dawn to dusk. The data is a GPS map co-ordinate accurate to 20 metres, flight speed and heading when the bird is flying, and the bird's altitude above sea level. This data is transmitted to satellites of the Argos CLS system and we obtain the results from them through our computer. The data for Mara and Breagha is then passed to the RSPB to update their sea eagle tracking website. We will map the same data when the young start to travel away from Loch Frisa, kind courtesy of the GoogleEarth Plus system which has revolutionised our ability to present geographic mapping of bird movements.