The core of our research work on The Wash is monitoring the birds that rely on its mudflats and surrounding habitats. We started catching and ringing waders 70 years ago, when we were simply trying to work out their migration routes and breeding grounds. Now we still aim to catch our study species regularly and continue to learn about migration, but we also check the ‘health’ of the population: are they putting on enough weight for the winter or have they completed their moult on time? How do they move around The Wash? Our regular catches help us to answer these questions, as well as allowing us to keep track of the survival rates of a range of species.
Monitoring survival rates tells us how long an ‘average’ bird is living and if this is changing. We still gather valuable data from birds that we recapture, but for those species we catch fewer of, much of our survival data is now collected by resighting colour-marked birds. Resighting colour-marked birds has also taught us more about how the birds use both the intertidal area and the fields around the coast. Our focus is on the population and what is happening to that ‘average’ bird, but we also enjoy the excitement of catching birds which are older than most of our team members – something they can find hard to get their heads around after all, most birds show no visible signs of just how old they are.
Already this year we have caught two Oystercatchers that have beaten the previous British & Irish longevity record. On 1 February, we caught over 300 Oystercatchers on the beach at RSPB Snettisham – nearly 100 of which had been caught before – lots of valuable survival data! However, when we were taking measurements from the birds, we noticed a very old ring. The bird was ringed by Moss Taylor at Weybourne (Norfolk) when it was a chick, back in 1983 – making it over 41 years old and beating the previous record (held by an Oystercatcher ringed on The Wash and sadly shot in France in 2017) by over six months. Oystercatchers are site-faithful, and this bird may never have left Norfolk, but simply commuted between Weybourne and Snettisham each year, while most of the Oystercatchers it flocks with on the Wash in the winter head off to Norway to breed.
However, we had a very unexpected surprise a few weeks later. Only a month and one day later we were on the other side of The Wash in Lincolnshire, we caught just over one hundred Oystercatchers (and five Knot), at Friskney. We had fewer than 20 recaptures on this occasion, but again, we noticed an old ring when we were measuring the birds. This was a bird we had ringed at roost on the Inner Trial Bank in March 1982, making it over 43 years old! Indeed, as the bird was in full adult plumage when it was ringed, it would have been at least three years old then, so it must now be approaching its 50th ‘hatchday’.
These very long-lived birds are unusual, but not entirely unexpected, as ringing has shown us that many Oystercatchers make it into their 20s or 30s. However, their record-breaking lives emphasize the value of The Wash for these and many other waterbirds. The Wash is a vital winter and migration stopover site which is internationally important for many of the species travelling along the East Atlantic Flyway. It forms part of England’s ‘East Coast Wetlands’ which span the coast from the Humber to the Thames. The ‘East Coast Wetlands’ were added to UNESCO’s Tentative List for World Heritage status in 2023, potentially ranking it alongside other World Heritage sites, such as the Galapagos Islands and the Great Barrier Reef, in importance for wildlife. The data collected by WWRG will hopefully provide some of the backing for the WHS bid and continue to help to protect these vital and beautiful wetlands.
Cover image by Sam Franks.