It’s the end of another season here at Cemlyn! The season has flown by here, but Zak and I have had a great season.

Right at the start of the season, we saw birds returning over a week earlier than normal, with birds quickly settling onto nests. Over the course of May, we were counting a maximum of 1,000 Sandwich terns sitting on nests which is about half of last year's numbers. On our clutch count, when we went out onto the islands under a license from Natural Resources Wales (NRW) and counted all the nests, we came back with a total of 2,167 Sandwich tern nests! Over twice as many as we were expecting to see, which later rose to a final figure of 2,400 pairs of Sandwich terns. This is 400 pairs higher than last year which is a great sign to show numbers are recovering well after the Avian Influenza outbreak in 2023. In the end, around 2,000 juvenile Sandwich terns fledged from the colony which is a great number.

The lower-than-expected number of around 1,000 Sandwich terns earlier in the season is due to a few factors causing the birds to nest in different areas of the islands compared to previous years. Sandwich terns like to nest in patches of thick vegetation which is usually plentiful on the islands in May. We think a combination of Winter flooding on the islands and the drier than usual Spring led to what vegetation was present to have very stunted growth. As the Sandwich terns saw that there were only a few patches of thick vegetation, they all decided to cram into the small spaces together, with many hidden from view in little ditches and channels on the islands. Over the next few months, the vegetation grew to create a dense forest of sea beet, annual sea-blite, and orache.

The exciting news this year has been the roseate terns. This season saw two breeding pairs at the colony, which sadly both failed, but is an amazing sign for the future of these birds at Cemlyn. At least 19 different roseate terns visited throughout the season with an amazing influx in the latter half of June with up to 15 different individuals recorded within two weeks. Roseate terns used to be regular breeders at Cemlyn until 1994, so this is amazing to see!

Black-headed gulls, common terns and Arctic terns all successfully raised young this year, but not as many as we were expecting. Around 80 black-headed gull and common tern juveniles, and around 30 Arctic tern juveniles managed to fledge from the colony.

Cemlyn received at least 6,742 visitors, which is the most we’ve ever had here by several thousand, with numbers greatly boosted by the presence of roseate terns throughout the summer. An amazing £636.67 (along with €3.51 and $0.1!) was raised this season thanks to the donations of the public, which will go right back to protecting the terns at Cemlyn.

Moth trapping has been very successful this season with 3,005 moths recorded over 177 species, with another 17 species seen elsewhere around the reserve. We had 19 species of moths that had not been recorded at Cemlyn before. 

Other wildlife was recorded including wildflowers, insects, fungi, and mammals with an amazing 807 species of wildlife recorded this season:

If you’re interested in seeing the full species list, you can find it here: 

Cemlyn Bay NWWT Cemlyn Bay Year List 2025 (807 species) | BUBO Listing

Thank you to everyone who visited and donated to the reserve this year, and a big thank you to our volunteers for dedicating so much of their time to the terns this summer. We wish the best for the terns which will soon be heading South to their wintering grounds and look forward to their re-tern next spring!