Any ID tips for terns in flight? (1 Viewer)

I am looking for any tips on the identification of terns in flight.
The terns I am trying to separate are common, artic and sandwich.
If I have a scope or binos, I can tell the sandwich from the colour of beak, but as far as the other two go, I am truly stumped. o .
We seem to have more terns here this year.
Many Thanks Kas

See if you can get a copy of this months (May 05) 'Birdwatch' magazine. There is an ID article on Commic Terns which should do the biz.

I'm not sure of the worth of the Bird Watch article. Obviously it's dead easy to tell them apart when perched.

Around my area the Terns are much fewer in numbers than usual, though more may arrive yet. Even Common Tern only arrived a few days ago.

A possible help in flying terns is that Arctic have quite dark breasts compared to Commons and their tail streamers are longer.

difficult unti you've seen a few definites

Arctic have a much more bouyant flight - this and their overall paleness lets you pick them out at considerable distance - once you've had a bit of practice

otherwise it's underwing trailing edge, primary pattern of upperwing etc

Tim

Hi kas,

At long distance, Common, Arctic (and Roseate) are pretty similar, Sandwich should be easier.

You'll need to study their fishing patterns to separate them. It's in the way they hover, 'stepped' hover, figure of eight, fly into the water ...

Take copious notes - it'll get easier

Andy.

If you're ever lucky enough to be able to study Common and Artic Terns flying together the longer neck of Common is obvious. But I'm not sure how useful a feature that is until you've head the chance to do a direct comparison. On Common Tern the dark wedge on the upperwing formed by the darker outer primaries is an easily seen feature:
http://capelookoutstudies.org/birds/gallery/photo020tn.jpg

On Sandwich Tern the wings appear to be set further back. There's much more "neck" than on "Commic" Terns and a shorter rear end.

Hi Kas,
here is a link to a comparative picture of Arctic & Common terns in flight: www.birdforum.net/pp_gallery/showphoto.php/photo/14556/sort/1/cat/500/page/30

I find the dark primary wedges on a Common useful, although they're a bit of a variable feature. They give the wingtips of Common an almost 'ragged' look, very different to Arctics where the primaries always look very clean and neat. I think Tim's comment about Arctic looking paler in flight, whilst I know what he means (the paler underwing) could be confusing because Arctics are actually darker underneath. On the deck Arctics generally give a darker impression than Commons both above and below.

In flight Arctics have a more 'bouncy' and flexible wing action and their wings look narrower based and placed further forward on the body. The shorter bill and smaller head are sometimes apparent.

The different feeding methods can also be helpful. Arctics can often be seen feeding in flocks, often quite far out to sea. They tend to hover above a likely area and perform 'stepped' dives. Commons tend to quarter coastal waters or estuaries, often (but not always) on their own and plunge straight into the water after fish, without the stepped hovering technique that Arctics use.

They're still tricky though.

Thankyou so much everybody, will go out this weekend and see if I get on any better.
Thanks again Kas. :clap: