Seabird experts have expressed concern over a slow start to the seabird breeding season and a drop in nesting activity.
Ecologists working for the National Trust for Scotland raised concern after analysing data gathered by the conservation charity’s annual monitoring surveys.
James Crymble, who worked as a seabird researcher on islands around the world before joining the trust, said the disappointing results could be partly due to recent outbreaks of avian flu.
He said: “Preliminary results are in from our rangers’ recent monitoring surveys and, though numbers do seem to be down for many species, it is not all doom and gloom.
“Kittiwakes, which had undergone dramatic population declines in Scotland over the last 30 years, appear to be bucking the trend this year with numbers increasing at most of our locations.
“It is a mixed picture for other species at our sites, with no fulmars breeding on Canna this year.
“However, their numbers are looking better on Fair Isle, making it larger now than St Kilda, which has traditionally been the largest fulmar colony in the UK.
“We are working to determine the root cause. We suspect for some species that part of the reason for the poor breeding season may be a knock-on effect from the avian flu that has been having a devastating impact on Scotland’s seabird populations in recent years.”
Elizabeth Morgan, a seabird scientist and qualified bird ringer, said poor weather conditions and a lack of food could also be factors in the results.
She said: “Some of these declines in seabird numbers, such as great skua, can be put down to the impact of avian flu over the last couple of years, but other things will also have impacted population numbers and nesting activity this year, too.
“We suspect that the drop in numbers may be due to poor conditions experienced by birds over winter, such as stormy weather, which makes it hard for them to feed, and a lack of food more generally.
“Seabirds will sometimes take a sabbatical, taking a year off from having chicks, especially if they are not feeling at their best, which may be the case for some birds this year. So, there is hope things will improve next year.”
Both ecologists will be working with senior seabird officer Ellie Owen alongside a team of rangers to complete twelve new initiatives designed to boost Scotland’s seabird species.
NTS figures showed that on Staffa, shags have experienced a “massive” decline from 52 nests last year to just 14 nests this year.
At St Abbs, shags also declined “dramatically” from 126 nests last year to 37 nests this year, though the gannet population saw an increase of 24% this year and kittiwake numbers are up by 9%.
Ms Morgan said: “In response to avian flu, we are increasing our monitoring effort for affected species and looking at ways to support their recovery.
“The main project involves collecting samples from birds and fitting them with coloured rings as part of a wider Ecoflu study led by Edinburgh University.
“The study aims to look at the levels of immunity in populations of great skuas and puffins throughout Scotland, that will allow us to understand if birds have immunity, how they were infected, and potentially how to prevent another outbreak.
“Fitting the seabirds with coloured rings gives them an individual identity, so they can be tracked throughout their lifetime.
“It will help us to better monitor the survival of the skua population on St Kilda as they recover from avian flu.
“In the last few days avian flu has again been detected in Scottish seabirds. This underlines how important our work is to monitor avian flu and support our seabirds while they endure this additional pressure.”
