July 18 – Scottish scientists will fit GPS trackers to up to 35 white-tailed eagle chicks over the next two years to help assess the extent of sea eagle predation on lambs and sheep, according to government nature agency NatureScot.
Licensed ornithologists will fit the GPS tags to the chicks of Scotland’s largest bird of prey at around eight weeks old, before they leave the nest from around 10 weeks of age, NatureScot said on July 17. The trackers can last for years, and will provide insight into where the juvenile birds travel after leaving their natal home range, the agency said.
The project targets Argyll, the Highlands and the Western Isles in the west of Scotland for tagging, according to NatureScot. Ornithologists will also try to fit five satellite tags to adult breeding eagles, building on advice and techniques from European counterparts used earlier this year to trap, tag and release an adult on the Western Isles.
Credit: Jacob Spinks, CC BY 2.0 via Wikimedia Commons.
The white-tailed eagle (Haliaeetus albicilla), also known as the sea eagle, became extinct in Scotland in the early 20th century due to human persecution, and was initially reintroduced on the Isle of Rum between 1975 and 1985, according to NatureScot. The species, now protected, has successfully repopulated the west of Scotland, with growing impacts on upland and hill sheep flocks, the agency said.
“This project will greatly add to our understanding of how sea eagles move around and their interaction with livestock,” said Andrew Stevenson, senior ornithologist with NatureScot. “A key gap in our knowledge is what role immature eagles play in predating livestock, given they wander widely during their first three to four years until they settle on a territory.”
Tagging is the best way to get a handle on what these juvenile eagles may be doing, and will also help understand other topics such as interaction with wind farms, according to Stevenson.
Scotland hosts around 200 breeding pairs of white-tailed eagles, with the birds mostly present in the west but spreading across the country, according to NatureScot.
Scotland’s Rural College SRUC is tracking lambs in Argyll using GPS neck collars in a separate research project, which will complement the sea eagle tagging project and provide a broad picture of how sea eagles and lambs interact, NatureScot said.
Farmers’ union NFU Scotland said understanding how eagles interact with livestock is critical to farmers in affected areas, and the research must lead to “practical, targeted management solutions” that give its members confidence that impacts on livestock are properly recognised and addressed.