'Each season brings a different experience at our nature reserves. In spring, the air is filled with birdsong as they compete to establish territories and attract a mate. In summer, look out for young birds making their first venture into the outside world. Autumn brings large movements of migrating birds - some heading south to a warmer climate, others seeking refuge in the UK from the cold Arctic winter. In winter, look out for large flocks of birds gathering to feed, or flying at dusk to form large roosts to keep warm.'