There were mixed fortunes for Northern Ireland’s seabirds in 2019, but monitoring that year also confirmed the importance of the country’s coastline for its 22 breeding seabird species. Key findings of the Northern Ireland Seabird Report 2019 include promising news about Kittiwake numbers. The Red-listed Kittiwake is in long-term decline in the UK as a whole, with numbers of breeding adults standing at less than half their 1960s total. However, this decrease is happening at a much slower rate in Notherern Ireland, and some colonies are actually showing a long-term increase. In 2019, Kittiwakes in Northern Ireland had a good year, with increases at all sites. The colonies The Gobbins and Muck Island fared particularly well, with numbers increasing by 68% and 65% respectively compared to 2018. Razorbills and Guillemots also did well in 2019, the former being recorded in its highest numbers since records began at Muck Island and the latter having its best year since 2016. It is not all good news, however. Fulmar numbers continue to decline, along with Black Guillemot, at Northern Ireland’s best known seabird haven, Rathlin Island. The annual recording of seabird numbers by volunteers is vital for capturing the long-term changes in Northern Ireland's breeding seabird population, and alerting policy makers to the need for conservation action.

Earthworms are vital for soil health, but concerns are being expressed about declines in their populations. Newly published BTO research shows how counting some of our best known birds can reveal important information about the number of earthworms beneath our feet. We have very little information on how earthworm numbers and soil health have changed over recent decades. This new study enlisted the help of over 20,000 children from schools up and down the country as part of our 'What's Under Your Feet' project. The children dug up small patches of their playing fields and counted how many earthworms they found. The young citizen scientists also counted the birds on those fields. The results showed that the numbers of earthworm-eating birds, including Blackbirds and Robins, were strongly linked to the number of earthworms present. Importantly, there was no link between earthworm numbers and counts of bird species that do not eat worms, such as Goldfinches and House Sparrows, giving the scientists behind the study confidence in the results. Although there is more work to do, this research opens up the exciting possibility that monitoring long-term changes in the populations of some well known bird species could help us to monitor not only the health of our earthworm populations, but the health of our soils too. Lead author of the study, Blaise Martay, said “It has been fantastic to see how much children have enjoyed digging up worms! And it is even better that this is paired with providing useful data and interesting results. Wouldn’t it be great if we could establish this as a long-term monitoring scheme to see what’s happening to our earthworm populations and to explore the links between earthworm and bird populations further? And hopefully this project will start many children off on a lifetime of citizen science looking out for our wildlife.” BTO’s Director of Science and study co-author, James Pearce-Higgins, said “Populations of birds like the Song Thrush and Mistle Thrush which rely on earthworms have been in long-term decline, particularly in southern England. The results of our new study add to the suggestion that a reduction in the availability of earthworms, either due to changing land-use or an increase in the frequency of summer drought conditions, may be partly to blame. We will continue to work to understand more about changes in soil invertebrate populations and how those are affecting our birds.”

Birdwatchers travel further to sites with rarer species, creating spatial bias. For 138 bird species we ran occupancy models for spatially biased and unbiased data. On average, occupancy estimates from spatially biased and unbiased data were aligned. We added weights to occupancy models, describing the probability of sampling. In areas with low sampling density, weights improved accuracy, but not precision.