A ‘flyway’ is a major migratory route used by birds to move between their breeding areas and the places they spend the winter. Several of these flyways or ‘superhighways’ for migratory birds exist around the world.
The East Atlantic Flyway, which incorporates the coastline of East Anglia is one of a few major global bird migration routes. It stretches from the tip of South Africa right through to the Arctic Circle. For coastal birds such as wading birds, the route flows up the west coast of Africa, around Spain, Portugal and France. On reaching the UK, the flyway then splits several ways - one lane heading up through Iceland to Greenland and Arctic Canada, one to Scandinavia, and another to Siberia. The flyway comprises at least 75 countries and is used by 90 million birds from at least 297 different species.
The habitats on the East Atlantic Flyway, such as wetlands, saltmarsh and mudflats, are of global importance for migrating birds. Here in England the 170,000 hectares of the English east coast wetlands network are a key part of the flyway.
These migratory routes are used by many different types of birds including wading birds and other waterbirds such as black-tailed godwit, dunlin and a wide range of duck and goose species and are likely to have been used for generations. They are much like aeroplane flight paths, with designated stopovers for re-fuelling. Not all birds using the East Atlantic Flyway will fly the entire distance from Africa through to the Arctic. Different species will use different sections of the route, some travelling further than others. The Arctic Terns which use the East Atlantic Flyway make one of the longest journeys along the route – from Northern European breeding sites to beyond the tip of southern Africa and as far as Antarctic waters - an amazing and mind-boggling feat.
Along the route are a number of ‘pitstops’ which are vitally important resting and feeding grounds for the birds. One such pitstop in the east coast wetlands network is The Wash, the largest estuary in Britain, spanning 20km across and 30km in length. The vast expanse of mudflat is covered twice daily by the North Sea and is surrounded by sandy and shingle beaches, saltmarshes and hidden lagoons. The Wash and its surrounding area is a haven for weary bird travellers. The receding tide uncovers a veritable buffet of highly nutritious morsels, the mud contains an abundant source of marine worms, shellfish and small fish. The surrounding saltmarsh provides further feeding opportunities as well as a comfortable and safe resting and roosting space.
Several RSPB reserves in this area are major pitstops. Wetland sites such as Titchwell Marsh and Snettisham in Norfolk, and Frampton Marsh and Freiston Shore in Lincolnshire all hug the coast or edge of The Wash itself. Tens of thousands of wading birds, geese and ducks can be seen on these wetlands throughout the autumn and winter.
Alongside being a pitstop, The Wash and the surrounding east coast wetlands area holds up to 400,000 wading birds, ducks and geese over the winter, that’s more than any other estuary in the UK. The area also hosts the largest common seal colonies in the UK, with the sandbanks littered with baby seals during pupping season - and some grey seals too.
The Wash is surrounded by saltmarsh, a vital soft sea defence, the vegetation on the edge acts as a buffer, breaking the force of the incoming tide and reducing the chances of sea walls breaching, leading to flooding. It also decreases the pace of the incoming water, slowing the flow as it returns to the sea.
Saltmarsh also plays its part in combatting climate change, burying carbon deep down underneath layers of sediment, which can remain locked away for centuries. Carbon capture and sequestration on saltmarsh occurs through CO2 being removed from the atmosphere by plant growth. It’s believed that one hectare of saltmarsh can store two tonnes of carbon.
In recognition of its global importance to people, place and wildlife The Wash was recently backed by the UK government, as part of the English East Coast Wetlands potential UNESCO World Heritage Site, putting it amongst some of the planet’s most important places for nature like the Great Barrier Reef and the Galapagos Islands.
Bird migration is centred around the seasonal availability of food and suitable habitats. The far northern winter is too harsh to provide enough food, birds must travel to places they know have what they need. The Wash and the surrounding area is just the ticket. With the vast expanse of mudflats and saltmarshes plus the additional areas of wet grassland there’s everything these birds need.
From July onwards the influx of birds is notable. It begins with a trickle, a few wading birds travelling through, dropping in for a rest and to feed up. Wading birds such as ruff, which do not breed here, are suddenly seen in sometimes quite large numbers on east coast wetland sites. They will hang around feeding and replacing valuable calories lost while flying before some of them move on further south. They, and a number of other species, may make several stops on other wetland areas on the East Atlantic Flyway. Places such as The Wadden Sea World Heritage site, at the heart of the flyway, see many thousands of birds on migratory journeys as do sites such as Banc d’Arguin in Mauritania and the Bijagos Archipelago in Guinea-Bissau as birds continue to move further south.
While many birds will stop at The Wash to feed for short periods, many wading birds and wildfowl arrive in the area to undertake their annual moult. Post breeding birds moult their breeding plumage and their old worn flight feathers, regrowing a complete new set in readiness for the next 12 months. The moult process requires a lot of energy and takes several weeks to complete. The Wash is a safe space and a high-quality feeding area, just the right place for the birds to undertake this process.
Brent geese, as with all geese and swans, are long-lived birds - the eldest known to be over 28 years old. Their knowledge of places stays with them and is passed down through generations. The geese arriving on our shores this autumn will have ancestors who did the same decades or maybe even centuries ago.
For more information about RSPB Titchwell and Snettisham see rspb.org.uk
