RSPB Lakenheath Fen: Meet the Fen’s creatures of the deep

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Visitors come to RSPB Lakenheath Fen for many reasons – to watch birds, admire butterflies or maybe just to enjoy a nice walk. But there are other hidden wonders to find and mostly, it is just the children who attempt to spot this secret life. The staff and volunteers know the delights that can be found....

I am of course talking about the ‘creatures of the deep’ – the amazing wildlife that make their homes in our ponds and ditches. Lurking beneath the surface of the water are many fascinating things. Water beetles, snails and wonderfully named creatures like the rat-tailed maggot, which will eventually turn into a hoverfly.

Personally, I always enjoy finding dragonfly nymphs in a pond. These nymphs are quite alien looking, with a hinged jaw that shoots out quickly to catch prey. During their time underwater they eat as much as they can, preying on leeches and even small fish. When it’s time for the adult dragonfly to emerge, they crawl out of the water up a nearby plant stem. They break out of their last skin, leaving behind a hard case (exuvia) which you might find if you look closely at the base of pond vegetation. The photo shows one that we found clinging to the edge of our raised pond outside the visitor centre – the adult dragonfly had long since flown away.

Another good find in the pond is the cased caddis fly larva – or ‘stick with legs’! The larvae make their cases out of objects they find in the pond, such as a small hollow twig, grains of sand and bits of leaf. You might overlook a cased caddis fly larva at first, until a small head pokes out of that twig you were looking at and the twig starts marching around.

You don’t just have to look in the water of course. You can see pond skaters skimming across the surface, dragonflies will buzz from side to side – always check the water lily leaves for resting damselflies. You may even be lucky enough to spot a grass snake swimming through the water! Ponds attract such varied wildlife; they are a great addition to your garden if you have the room.

If I’ve tempted you to try and find these amazing creatures yourself, come along to Lakenheath Fen and have a go! We’re holding a ‘Monsters of the Deep’ event on 16 August, when we’ll be on hand to help you uncover this mysterious world. Other sessions taking place on this Fenland Wildlife Bonanza day include mini-beast hunting and a bird ringing demonstration.

See our website for details or give us a ring – 01842 863400.

Alternatively, simply drop in to the visitor centre and ask about pond dipping. We can lend you the equipment, identification sheets and help you get started. Please make sure you use our equipment, so that we don’t get new and unwanted creatures or plants introduced into our ponds and ditches. Come and explore this fascinating other world for yourselves!