Geograph - photograph every grid square

it is popular with bird-watchers - twitchers - who stay for a few days when studying the bird life

Strictly, twitchers will be after one particular rare bird and it is unusual for them to even stay one night - drive in (often through the night), see the bird, drive back in the afternoon is often the form. Birdwatchers or birders (difference being birdwatchers look at the weather forecast to see if it will be a nice day for them, birders look at it to see what birds it will bring from where) are more likely to stay and studythe birds in an area over several days.

Nitpicking over, it is a really good area for birds - tens of thousands of geese and ducks in winter, thousands of migrants passing through spring and autumn and some good breeding species being the highlights.