There has bee great debate about this bird and who wouldn't speculate on a rare duck when turns up in the UK... A nice drake Baikal Teal was found amongst the hundreds of Teal and Wigeon at Crossens Outter Marsh. Consider that it could be a hybrid, it was soon ruled out and thought to be either a first winter bird or an adult. The speculation came about because the bird was missing a black tear drop under its eye. Birds are known to appear in the wild and it is reported that 6% of these drakes have this feature.
I ain't going to bore and go on about all these features and what it could be or not... to me, it appears to be okay to have this feature missing. Again, it could be a feature of an affect to moult so if it stays for the winter, we may learn a lot more about these birds.
Martin Garner covers the speculation in more details and can't see a reason to why it isn't genuine. The bird is spending a lot of its time with the wigeon which is another plus point as these birds breed in a similar area. For more please visit Martin's blog: http://birdingfrontiers.com/2013/12/07/baikal-teal-at-southport-first-winter-or-adult-male/