Royal Tern split into two species

27th January 20202

Royal Tern has been split into two species by the IOC as part of the the latest (10.1) update to its World Bird List.

West African Thalasseus albididorsalis has been recognised as a different species to [American] Royal Tern T maximus, and has been dubbed West African Crested Tern.

The news comes as little surprise – 2017 research showed that West African Crested Tern was in fact a sister taxon of the smaller Lesser Crested Tern rather than similar-looking [American] Royal Tern, and that its then treatment as a subspecies of Royal Tern was misleading. This was supported by both the mitochondrial and nuclear DNA. These revelations come despite the fact that Royal and West African Crested Terns are morphologically near-identical and, in many cases, nigh on impossible to separate in the field. 

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Rare Royal Tern makes an appearance on Anglesey

Bird Notes columnist Julian Hughes of RSPB Cymru reveals what birds have been spotted in the past week and lists 10 upcoming birding events

Andrew ForgraveRural Affairs Editor

23:05, 10 DEC 2018

Anglesey's Royal Tern's metal ring suggests it was originally from North America (Image: Tony White)

A Monday lunchtime visit to Traeth Dulas, north of Moelfre, proved an excellent decision by Angleseybirder Tony White, who found a Royal Tern on the incoming tide.

It flew out to sea but was refound at nearby Traeth Lligwy, enabling local birders to catch up with this mega sighting.

It’s not the first Royal Tern to visit North Wales. One on the Llŷn Peninsula in June 2009 relocated to Llandudno for a few hours and attracted birders from across the UK, though its short visit meant that only locals got to see it.

I remember a frantic dash from West to North Shore to follow the bird as it flew across town.

But not all Royal Terns are the same. It’s the second largest species of tern, with populations on both side of the Atlantic.

Recent studies show that Royal Terns nesting in West Africa are genetically distinct from those that breed from North Carolina south to Argentina, and some authorities consider them to be different species.

The problem is that birds from each population look very similar, and the Llandudno bird couldn’t be assigned to one or the other.

This week’s Anglesey bird sports a metal ring on its right leg, consistent with a ringing scheme in North America, indicating its likely origin.

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