One of Scotland’s most iconic birds will be the subject of a fourth national survey to see how its population is faring. The six-month survey of golden eagles is co-funded by Scottish Natural Heritage (SNH) and the RSPB. Licensed surveyors RSPB Centre for Conservation Science in collaboration those from the Scottish Raptor Study Group will spend this time recording the number of these majestic birds, known for their spectacular undulating flight displays in spring.
All of the golden eagles in Great Britain are found in Scotland expect for a solitary male in the Lake District. Much of the population is in the west Highlands and islands of Scotland.
Long term monitoring has shown that although the golden eagle population has remained stable there is a variation in numbers across different areas. The most recent survey in 2003 revealed that the overall number of breeding pairs had increased, since 1992, by 20 to 442. However, there were declines of 24 per cent and 28 per cent in North Central and South Central Highlands respectively, since the first survey in 1982.
Dr Daniel Hayhow from the RSPB Centre for Conservation Science highlighted the need for the survey: “This national survey is really important to the conservation efforts for golden eagles. These birds don’t breed until they are four or five years old so having accurate numbers of breeding pairs will help us assess how the population is faring at the moment and in the future.”
Researchers are keen to find out whether conservation efforts over the last twelve years have led to an increase in breeding numbers across the country. The survey will cover all current known golden eagle hunting and nesting areas, called ‘home ranges’. Areas where golden eagles have previously inhabited will also be assessed to check for any signs of their return.
To observe and count the golden eagles, the licensed surveyors will visit each possible home range three times, first to look for the birds or signs of their presence, then to check if pairs are breeding, and finally to see if they’ve been successful in producing chicks.
Golden eagles were once common across Great Britain but had disappeared from Wales and England by the mid-19th century due to widespread persecution. Part of the surviving population in Scotland suffered a sharp decline in breeding success in the 1960s due to organochlorine pesticides which caused mass infertility and eggshell thinning.
Although numbers of these majestic birds have slowly recovered they continue to suffer from a series of challenges such as changes in upland management and afforestation in some areas. Wildlife crime is also an issue: between 2003 and 2013 17 golden eagles have been confirmed illegally killed in Scotland.
Andrew Stevenson, SNH ornithological adviser, comments that: “Although around half the golden eagle population is monitored every year by the Scottish Raptor Study Group, these broader national surveys are vital to fill the gaps on the status of the whole population. We use the results of these surveys to make decisions about the future conservation of the golden eagle.
“Golden eagles face a range of issues. Persecution is a major concern in some areas, but poor quality habitat with reduced prey is also a worry in parts of the west Highlands. Intriguingly, there has been a suggestion in recent years that some pairs have learned to cope with fairly extensive forests, despite it being a factor in some range losses historically. The potential risks from renewables have also increased as the industry grows.
“Clearly, the factors affecting the conservation of golden eagles need us all to work together. One example of this is the recent study of the golden eagles in Southern Scotland with an aim of working with all types of groups – from conservationists to land owners to public bodies – to improve the low number of occupied ranges there.”
Patrick Stirling-Aird, Scottish Raptor Study Group Secretary says: “The Scottish Raptor Study Group welcomes this survey and considers that a review of the overall population status of the golden eagle is now due, twelve years having elapsed since the last full national survey took place. The Scottish Raptor Study Group will be particularly interested to see what, if any, recovery in golden eagle numbers in parts of the central and eastern Highlands has occurred since 2003, by which time there had been in those areas a marked decrease in golden eagle numbers from the substantially higher levels of territory occupation recorded in the previous national survey years of 1992 and 1982.”
Dr Amy Challis, Scottish Raptor Monitoring Coordinator at the Scottish Raptor Monitoring Scheme says: “Every year hundreds of dedicated volunteers spend many hours monitoring raptors across Scotland and contribute data for all raptor species to the Scottish Raptor Monitoring Scheme. The backing from SNH and the RSPB for the national survey brings together our volunteers with other licensed surveyors so that near complete coverage can be achieved. This gives us the most accurate picture possible of the status of the current breeding population.”
Dr Daniel Hayhow from the RSPB Centre for Conservation Science adds: “Seeing a golden eagle soaring across the sky is a wonderful sight but this shouldn’t be a once in a lifetime experience for people. Golden eagles were previously found across most of Great Britain and it is directly because of the actions of people that they are now almost all confined to certain areas of Scotland.
“The information gathered by the previous surveys and historical records allows us to target the areas our team of surveyors will concentrate on for the next six months, and we’re really grateful for the support we have from farmers and landowners. To gain an accurate picture of golden eagle numbers each home range must be surveyed three times in this period. With some birds known to nest as little as 2km apart in the same glen this will be a very thorough process that will guide our conservation efforts for these birds over the next decade.”