One good tern deserves another.

Arctic tern

One of my favourite places in Wales is Cemlyn Bay, on the north coast of Anglesey. It is a brackish lagoon separated from the sea by a curving shingle spit. Within the lagoon are a couple of islands on which very large numbers of terns raise their young every year. Commonest is the sandwich tern, with large numbers of common and arctic terns as well; it has held roseate terns in the past and occasional birds are seen every year, although they do not now breed.

Several roseates were reported earlier this summer, which encouraged me to plan a visit for later in the year; I had never knowingly seen one before. Then in July an elegant tern took up residence within the colony; this is a very rare visitor to the UK and is normally found on the western coast of northern and central America. I decided to bring forward my visit to try to catch both species together.

Tern identification has never been my strongpoint. Sandwich terns are pretty unmistakeable but I tend to lump most arctic and commons (let alone roseates) – unless seen very well – as “comics”. However, Cemlyn Bay is one place in the UK where with a little bit of time and patience one can get to grips with this tricky ID problem. From the safety of the shingle ridge it is possible to get excellent views of the terns on the islands even without a telescope.

A sandwich tern on steroids……..

It wasn’t difficult to locate the elegant tern. It has a massive bill the colour of a banana and over a period of a couple of weeks it had established a “territory” centred on one of the unoccupied roseate tern nesting shelters. It would perch there and display to any passing sandwich tern. It is basically a sandwich tern on steroids and in my opinion has been badly mis-named. It is large and chunky, with a backward-pointing crest, but ‘elegant’? Sorry but no!

The roseate terns were another matter altogether. One of the Wildlife Trust wardens pointed one out and yes…… I could see it. But would I be able to pick one out in a crowd (of other terns)? Probably not. Every so often a “dread” would take place : the whole colony took flight and swirled around overhead for a couple of minutes before returning. On a couple of occasions the dread occurred when a hunting peregrine flew through the colony but often there was no apparent reason for it. On my first evening there it happened over and over again. I’m not sure if anybody knows why they do it but they do, and after one of them the roseate tern disappeared.

A dread…….

I was under no time constraints and particularly enjoyed the delightful approachability of the arctic terns. They would alight just a few yards away on the shingle without batting an eyelid, or fly from the colony past the observer to the sea at a similar distance. Fledglings lay prone on the ridge waiting to be fed and their parents would bring them sandeels no matter how close you were. It must be one of the best birding (and bird photography) experiences in the British Isles. Everybody should visit Cemlyn at least once!

Roseate tern (or is it…..?)
Spot the difference…….

During the afternoon, as the tide receded, more and more terns rested on the beach, sometimes no more than ten yards away. It gave me the chance to examine them in detail. I picked out one individual with a black bill, one of the most noticeable features of a roseate tern. The more I looked, the more black bills I found, perhaps half a dozen of them altogether. Were they ALL roseates? Another birder examined them with a telescope and confidently told me that they were; I wasn’t convinced. Another said they were, in fact, first-summer arctics – despite the fact that they normally spend their entire first year in the Antarctic and are scarce in the UK. The secret is in the colour of their legs – roseates have (relatively) long bright red legs while those of the arctics are very dark red or black and very short.

Examining the images at home I picked out one which looked good for a roseate, and sent it for confirmation to the tern wardens. They agreed. But there’s a snag; the tail streamers on a roseate are exceptionally long and this bird’s just aren’t. So there’s one final possibility. On the Skerries, an offshore tern colony just a few miles away, very occasionally a roseate tern has mated with a common and reared young. So could this be a hybrid? We will probably never know.

N.B. Apologies for the terrible pun in the post title, and to many of you whose interest in the minuteae of tern identification is………err………limited…..! But I’m sure you’ll agree, they’re stunning little birds.

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3 thoughts on “One good tern deserves another.

  1. I was there at the end of July, saw all the terns except roseates – though I’ve seen them on other occasions. It wasn’t until I was looking through my photos back at home that I realised that although I had plenty of photos from previous visits, hardly any were of Arctic terns. Fortunately, there were a few very obliging ones this time. And this time I also got photos of juvenile commons and Arctics. It’s certainly a place worth visiting a few times.

    1. Apparently, arctics used to be less common at Cemlyn Bay. Then last year the entire tern colony on the Skerries deserted, and quite a few of the arctics moved to Cemlyn. And some of them have stayed,. Being very protective of their nests, they chase predators away more aggressively than the commons and sanwiches do, so the colony has been more successful this year. That was the thinking I heard while I was there, anyway……..

      Nice to have you onboard the blog, by the way. A post on choughs will follow shortly!

      1. I have a half-written blog post about the terns that I really must get around to finishing. It was quite interesting to find out about the history of the colony, and it matched with the photos and notes I’d made of my visits.

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