The high and lows of Cemlyn in summer 2023

The high and lows of Cemlyn in summer 2023

Sandwich tern © P. Evans

2023 was certainly a mixed season at Cemlyn and as this year's wardens - Mark, Dawn, Hannah & Ruth - say a fond farewell, they look back on the summer

2023 started off with an unexpected turn, as Mark faced the prospect of lone wardening - but a crack team was soon assembled… enter Dawn, Hannah and Ruth!

Cemlyn wardens 2023

L to R Hannah, Mark, Ruth and Dawn - Cemlyn Wardens 2023

For the terns, the season began slowly as cold weather delayed arrivals and mating. A few weeks in we began to realise the effect of the previous year’s avian influenza on the terns as we saw much lower numbers returning. Worries increased when herring gulls started to predate black-headed gull eggs and frequently disturb the colony.  Then came the second strike of avian flu… We were able to control the spread to some extent at the beginning by removing the dead bodies. As chicks started to hatch, we decide not to collect bodies from the islands, for fear of disturbing the colony and exposing the chicks to the bad weather and predation. From then on, we just had to hope, monitor other predators and human disturbance. It has been a challenging and upsetting season in this regard.

To determine the effects of avian flu on the Cemlyn colony, we assessed the damage done in terms of the effect on the adult population (with reference to the size of the breeding population and productivity) and the number of chicks successfully fledged . The Sandwich terns were the worst affected in terms of productivity, with around half of the chicks affected (followed by common terns, and lastly Arctic terns). Although, when we look at the adult population, common terns were the worst affected (perhaps adult birds being more susceptible to the disease than the other tern species?), then Arctic and then Sandwich.

Despite all this, we have seen chicks of all tern species fledge successfully, and we are extremely grateful for this. Hundreds of Sandwich tern chicks will follow the adults back to their wintering grounds.  However, we will only know the true effects of the disease next season when we can see how many birds have returned to the breeding colonies.

For now, we have now cleared the islands of the dead birds to help ensure that the disease is not spread through carrion eaters and winter birds visiting the reserve. But we ask that you still follow the guidance on keeping dogs on leads and not touching dead birds or feathers.

We must also remember the other positives this season too! A few firsts for Cemlyn, and Anglesey!

  • The first pair of avocets to breed on Anglesey!! Producing four chicks. Even though the chicks didn’t survive (we think they were most likely predated as we found no evidence of any of these chicks on the island), who knows, the adults may return next year…
  • The first Pine hawk-moth for Anglesey.
  • The first Convolvulus hawk-moth for Cemlyn.
  • The first Ringed plovers to successfully breed on the ridge for many years!
  • A new site for breeding sand martins
  • A record number of little egrets (33 in one day!).

And,  we have seen a lot of other breeding success around the reserve. Most notably with the Red breasted mergansers, Shelducks and Swans. We have also observed lots of other fascinating invertebrate, reptile, mammal, marine and plant life!

The Wardens’ Walks this year have been a great success too – thank you to all that joined us. As always, a massive thank you to all the volunteers that have given up their time to help us on the reserve, carrying out our duties would be so much harder without you! Many thanks also go to the local birders, residents and friends, to all those who have donated over the season, and finally, thank you to all of you for following the season online with such enthusiasm, it all helps to keep us going! We are extremely appreciative of all the support shown for the conservation of this special place and, of course, our beloved terns.

As the season ends, we must hope that the terns can survive their long journey home. Fingers crossed that we will see the fledglings again in a couple of years, when they return as breeding adults. Good luck little ones, and adults alike…

5 young people walking away from the camera, along the shingle at Cemlyn Bay dressed warmly on a sunny day

© NWWT