With my girlfriend and I starting new jobs, today looked like our last chance for decent birding trip so we headed for a fairly safe bet,
Blacktoft Sands RSPB in East Yorkshire. I hoped to impress her with Avocet but the daytime tides weren't on our side, and we saw none. Apparently there are over 300 commonly scene on Read's Island just 5 miles east on the Humber, although the site isn't accessible to visitors.

Marsh Harrier showed well, toward the end three pirouetted in to roost. I think you could probably be 100% certain to see at least one during any visit at any time.
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video here)
We stayed late keeping at eye on the Barn Owl box, though we had no sighting in the vest strong winds at dusk.

A straggler Whooper Swan was probably the best local rarity, just pipping the drake Pintail and his two accompanying females.
Otherwise Black-tailed Godwit, Dunlin, Golden Plover and Curlew where in good numbers, with nothing better to pick out among them than a solitary Redshank. A couple of hundred Greylag flew in from the Humber late on, the Tree Sparrow in the car park were nice to see, and a decent smattering of ducks from Goldeneye and Gadwall to Teal and Tufted Duck covered each lagoon.
For anybody who hasn't been, it's one of the top three RSPB reserves in the region, with 6 spacious hide, plus a reception hide overlooking internationally significant reedbeds on the south banks of the Humber. And, thankfully, there are toilets.
Winter raptors can be good, my last visit a couple of months ago came up with a Merlin for example, Bittern and Bearded Tit are present although rarely scene in the vast expanse of the reeds, and Avocet breed there, should you visit in Spring/Summer.
62 species for the day.