Birdwatch: Green sandpiper

Forget the holiday traffic jams, put away the summer clothes and turn on the central heating - it may still be August, but in the bird world, autumn is officially here.

The first sign of the season arrived in the last week of July. On an evening's walk around my local patch, on the edge of the Somerset Levels, I heard a piercing call, almost as high-pitched as a dog whistle. Then a small wader swooped up into the sky, before disappearing into the distance: a green sandpiper.