thanks for your replies, looks like last week in april first week in may then

talking of the weather, how does it affect where the birds go? the reason i ask is we were down at slimbridge last week and visited on two different days. the first day, wednesday, was wet and windy and we saw loads of birds, including bewick swans

. the second visit, friday, it was calm, sunny and relatively warm....and barely a bird in sight! going by this, does it mean we're likely to see more birds when the weather's bad?