Aythya sp. at Swithland Reservoir. This admittedly very poor videograb shows the wing pattern clearly enough to show that this bird isn't a Lesser Scaup. The white clearly extends right across the secondaries and primaries; Lesser Scaup has white only on the secondaries. I personally think it is probably a Scaup x Tufted Duck hybrid - it's a bit on the small side for a Scaup, and has rather a lot of dark on the rear of the mantle.The head shape also looks a little odd for a Scaup, being rather flat-topped and showing a very slight nape bump at some angles. However, some local observers think that it is a Scaup, and the bill pattern is certainly right. Who knows?!