any ideas please

[gregA]

hi

Can anyone offer any ideas on the id of a bird i saw today.
It was flying along the thames at barking bay. I was scanning the river looking at some shelduck and teal when i lowered my bins i saw what i thought was a lapwing flying past sighting it up in the bins i quickly realised it wasn't a lapwing but couldn't id it.

it was black or very dark on top of the wings and body with lots of white on the underwings and a white belly and chest. It was about the size of a black headed gull and flew similar to a gull and had a short dark beak.
I know its not much to go on but does any one have any ideas what it could have been.

I know there have been some artic skuas on the thames at Rainham which isn't far away but it seemed to have more white on the underwings than photos i have seen. I also thought of oystercatcher but it didn't have a long enough beak and it was black.
gregA

[gregA]

i've just looked at some pictures of a manx shearwater and that is what it looked like but i don't remember it gliding at all as it flew and it was about 50ft above the thames and on the edge of london.
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[RoyW]

Have you considered Black Tern? It's fairly late for them but not unprecedented, and they can look very dark above.

[gregA]

thanks roy but i have looked at images of a black tern and this bird had a white belly and chest guess i'll never know for sure, just my luck that i never had my camera.
gregA