SCOTTISH birds of prey’s breeding success might have been impacted by avian flu, in accordance with a report printed by NatureScot at this time.
The widespread results of the virus on seabirds and wildfowl in Scotland and all through the U.Ok. have been properly documented, however the impact on birds of prey is much less well-known.
A brand new evaluation by the British Belief for Ornithology (BTO) discovered that the proportion of golden eagle pairs efficiently rearing younger declined from 48% in 2021 to twenty-eight%.
Throughout the identical interval, breeding success for white-tailed eagles dropped from 67% to 45%.
White-tailed eagles seem to have been most severely impacted in coastal areas, suggesting a hyperlink between contaminated seabirds that eagles might have scavenged.
The biggest declines recorded had been in Lewis and Harris, the place breeding success of golden eagles fell from 55% to 16%, and for white-tailed eagles declined from 66% to 24%.
The primary circumstances of avian flu in birds of prey had been detected in November 2021, and by April 2022, there have been optimistic check outcomes for a variety of species.
The research discovered proof for regional impacts on some species, comparable to decrease breeding success for ravens in Orkney and Shetland, and for peregrines in Tayside.
Nevertheless, these impacts look like extra localised than for eagles.
Different elements comparable to climate and prey availability can have an effect on breeding success in birds of prey, resulting in decrease brood sizes or fewer chicks fledging from breeding makes an attempt.
Nevertheless the 2022 information confirmed that full nest failures (with no surviving younger) had been extra frequent than partial successes.
That is per the impact of a extremely contagious and pathogenic illness comparable to avian flu.
John Allan, NatureScot Ornithology Advisor, stated: “Scotland nonetheless has sturdy eagle populations however these findings are very regarding.
“Up to now we have now had fewer optimistic check outcomes amongst birds of prey this yr than final yr, however it’s early within the season and we are able to’t be complacent.
“We intend to repeat this evaluation in 2023 to see if breeding success begins to enhance.
“All companions in Scotland’s Avian Flu Process Power are persevering with to work onerous to grasp this virus and take motion to make our wild chook populations extra resilient.”
Appearing Head of Science for BTO Scotland Mark Wilson stated: “We all know from laboratory checks for the virus in lifeless birds of prey that avian flu can kill each grownup and nestling raptors.
“Nevertheless, testing of reside and lifeless chicks is simply too rare to make certain about how widespread this illness was amongst raptors in 2022, or what number of of final yr’s breeding failures had been brought on by avian flu.
“Nonetheless, the findings of this research are per worrying impacts on Scottish eagle populations.