The black-headed gull is actually a chocolate-brown headed gull! And for much of the year, it's head even turns white. Look out for it in large, noisy flocks on a variety of habitats.

This huge gull can be seen around most of the UK's coasts in summer, with some venturing inland in winter.

The lesser-black backed gull can be spotted around the coast in summer, with the biggest colony on Walney Island, Cumbria. Look for it over fields, landfill sites and reservoirs during winter.

Nudibranchs, also known as sea slugs, are much like their land-based relatives that you may spot in your garden. But, unlike your regular garden slug, the nudibranch can incorporate the stinging…