Stonechat in the fog
'4 of 5 Pintails' - No, WIGEON - see Daniel's comment and my PS below. The birds were flushed by a dog walker, and flew east, just after I first saw them
Adult female Pintail have scalloped flanks, like Mallard, and none of these birds has that feature.
The front, top middle and rear birds have plain chestnut flanks and blackish backs, which I think makes them eclipse males. The rear bird has 2 male-type scapulars: black with pale margins.
The lower middle bird has plain brownish-grey flank and - slightly darker - back. I guess this is a juvenile.
The bills comprise a pale grey triangle over a dark grey base.
PS (1 October): I was taken in by the seemingly long necks (? birds alert to dog walker) and did not think of Wigeon (!), but this is clear given the chestnut flanks of 3 of the birds, the visible white inner forewing, and the bills which in Pintail would be longer and less stubby.