In the winter, the UK is home to vast numbers of resident and visiting waders. They flock to our shores, lasting out the water on our coastlines, but why? What are they looking for? RSPB President Miranda Krestovnikoff reveals what waders eat. Over to Miranda...
A flock of knots take up residence at RSPB Snettisham. Photo: Chris Gomersall (rspb-images.com)
Winter is a time to head to the coast. Wrap up warm and be prepared for a wait, but the reward is worth it – a cacophony of the most evocative sounds from the “peep-pe-peep” of the oystercatcher, to the haunting trills of the curlew.
Our estuaries are the place for the spectacle of millions of waders, gathering to feast on the calorie-rich contents of the mud. While the trees are bare and the fields empty, this monochromatic mass hides a wealth of vital food for refuelling local residents and winter visitors alike.
But what are they eating out there? Well, the mud is packed with all manner of worms, shellfish and crustaceans, all distributed in the mud at different levels. On the Mersey Estuary, each cubic metre of mud is estimated to contain enough worms and shellfish to provide calories equivalent to 16 Mars bars. Head out with bucket and spade and dig deep down to see what the mud contains.
Who eats what?
Each species of wader is perfectly adapted to feed at a different depth and on a different food source. Here are just a few examples.
Oystercatchers use their long beaks to probe the mud. Photo: Andy Hay (rspb-images.com)
Oystercatchers actually very rarely eat oysters. These black and white beauties are perfectly suited to life on the mud flats. That long, slender, orange bill probes down into the mud, feeling for small crabs or molluscs, and very occasionally oysters, which it prises open with that strong bill.
Avocets can both skim the surface and probe the depths with their beaks. Photo: Ben Andrew (rspb-images.com)
These birds (the RSPB's own emblem) sweep their long, curved bills from side to side, skimming shrimps, sand-hoppers and the larvae of midges, flies and beetles out of the water.
Those with shorter bills, such as grey plover, can only probe the mud's surface. Photo: Andy Hay (rspb-images.com)
With their short bills, grey plovers tend to feed on whatever is lying on the mud surface, including cockles, small shellfish, marine snails, lugworms, ragworms and bristle worms.
The beak of the curlew is the longest, reaching the lowest depths in the mud. Photo: Eleanor Bentall (rspb-images.com)
Our largest wading bird sports the longest bill. It is distinctly curved, to reach down to the deepest morsels.
Lapwings largely pick up food from the ground. Photo: Chris Gomersall (rspb-images.com)
With medium-length beak lapwings are able to eat invertebrates both on and in the ground, including earthworms, beetles, flies and snails.
The versatile beak of the knot can probe for food and eat plant matter. Photo: Andy Hay (rspb-images.com)
These little waders probe the mud for small shellfish and snails. In summer they also eat plant material.
Turnstones use their tough beaks to flip stones. Photo: Ben Andrew (rspb-images.com)
This shoreline bird can be seen flicking aside seaweed and pebbles with its strong beak, while it hunts for mussels, barnacles, insects and other opportunistic scraps.
Read more from Miranda in her Nature's Home magazine column. If you're not already a member, sign up to receive your copy.
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