BES Facebook pageBritish Ecological Society Press Release
Monday 12 September 2011
Ospreys need helping hand from humans to expand UK range
Ospreys will expand to southern Britain much faster if they are given a helping hand from humans, researchers will tell the British Ecological Society's Annual Meeting at the University of Sheffield this week. Their conclusions come from a long-term study of ringed ospreys breeding in north-east Scotland, which found they have a strong tendency to return to breed close to where they hatched.
Once common throughout the UK, the osprey was driven to near extinction by Victorian egg collectors during the 19th century. It was not until the protection of a breeding pair of ospreys in the 1950s at Loch Garten in Scotland that a slow increase in numbers began, and there are now more than 230 breeding pairs of the iconic fish-eating bird of prey.
But despite the best efforts of conservationists, who have at times guarded osprey nests round the clock to protect them from egg thieves, the ospreys have been slow to expand to new areas. Now, new data helps explains why this is the case.
For the past 40 years, Roy Dennis of the Highland Foundation for Wildlife has colour-ringed osprey chicks in the Scottish Highlands, allowing ecologists to keep tabs on breeding adults.
By comparing the breeding locations of around 100 ospreys in relation to where they fledged, researchers from the University of Leicester and the Rutland Osprey Project, working alongside Mr Dennis, have shown that most ospreys return to breed close to where they hatched.
According to Tim Mackrill of the Rutland Osprey Project and a PhD student at Leicester University: “Our analysis of colour-ringed individuals breeding in north-east Scotland and other parts of the UK showed most birds exhibited strong natal philopatry, returning to breed close to the site where they were reared. This has resulted in the development of ‘loose colonies’ of 10-20 pairs in distinct geographical areas and made the expansion to new areas slow. Despite this general trend some individuals, usually females, nest further from their natal site. Such individuals are important in the development of new colonies.”
As well as explaining why ospreys in the UK have been slow to spread to new areas despite large amounts of available habitat, the results of this long-term study suggest the birds need a helping hand from humans. This has been done at Rutland Water in central England, where 64 osprey chicks brought from Scotland between 1996 and 2001 are now breeding successfully.
“This study shows that moving osprey chicks from Scotland is the quickest way to restore the birds to other parts of southern Britain – natural re-colonisation will take much longer given the strong natal philopatry,” Mr Mackrill says.
Tim Mackrill will present his full findings at 12:45 on Monday 12 September 2011 to the British Ecological Society’s Annual Meeting at the University of Sheffield.
