If I were to search for a word to describe this hyper-active spark of colour it would not be "grey", but that's its name - Grey Wagtail. I suppose its back is grey and it certainly wags its tail a great deal, but you can see why many people want to call it "yellow", though that name is reserved for another wagtail which is even more yellow.
You rarely see them away from running water, and they especially like mountain streams, though they seem to do just as well on the sluggish steams of East Anglia. Perhaps the old country name of Water Wagtail describes them more accurately.
The male Gadwall appears at first glance to be a grey duck with a black tail and usually you can see a little white patch on its wing too. But when you look closely you can see tiny delicate patterns on the feathers - "vermiculation" is the word to describe it.
Mrs Gadwall is also subtly coloured in various shades of brown, quite like a female Mallard.
Lurking at the water's edge is a Green Sandpiper, though in this case its not as colourful as the name suggests. Officially it's a wader, or shorebird, albeit one that's rarely seen on the coast. They nest up in Scandinavia or northern Russia and, whereas most waders nest in a scrape on the ground, Green Sandpipers utilise the old nests of other birds, often quite high up in a tree. This means that the flightless hatchlings' first experience of life is a long fall earthwards.
Some Green Sandpipers overwinter in the UK, others pass north in Spring, while non-breeding birds start to come south again in Summer, before the bulk of them come through in Autumn. So all in all you might see one in any month of the year, though you'd have to be observant; most of them are nowhere near as co-operative as this individual!
This endearing ball of fluff is a Little Grebe. I was in a hide once when there were some children present who were convinced it was a "baby duck" and were surprised to learn from a wildlife warden that it was fully grown. They were even more surprised ("alarmed" might be a better word) when it abruptly disappeared under the water, never to be seen again. The warden assured them that it was quite normal behaviour and that the bird had almost certainly bobbed up again in amongst the reeds. I don't think they believed him though!
Three Tufted Ducks, two males and a female. They are common here especially in winter when their numbers are increased by birds coming south from more northerly parts of Europe. That tuft, which gives them their name, isn't always as obvious as it is here.
When you see a rough wooden box attached to an electricity pylon in a car park you might think that the person who put it there as a possible nesting site for a wild bird was being rather optimistic, but this Kestrel seemed to find it to his liking.