Contributed by John Sanders.
In the Septembers of 2010 and 2011 a total of 96 Curlews were trapped at the high tide roost at Wibdon Warth, Tidenham, and were fitted with unique combinations of colour rings. Birdwatchers were asked to look out for these birds, so that their site faithfulness and longevity could be determined. Sadly, enthusiasm seems to have waned, and I now find myself as the only person who has made recent records.
Curlews started to leave the estuary in early February, and all colour ringed birds had gone by the middle of April, so that only about thirty unringed individuals remained during May. These clearly did not breed, and were assumed to be first-summer birds, as it is generally agreed that Curlews do not start nesting until their second-summers (third calendar years). The return to ‘winter’ quarters started in the middle of June, and numbers rose rapidly at the end of the month and in the first week of July, so that soon over five hundred were coming into the roosts. These included several juveniles, but most were adults in very obvious wing moult. This suggests that the nesting birds start their moult before their young have fledged, and then quickly leave their breeding sites to return to the estuary.
It has been difficult trying to cover the three main roosts at Aylburton Warth, Guscar Rocks and Wibdon Warth in the prevailing wet and windy weather, but even so the results to date (12 July) have been very encouraging. I have seen a total of 61 colour ringed birds since mid-June. These have included individuals from presumed breeding sites in Oxfordshire and North Yorkshire, but, what is more surprising, is that two breeding birds from The Netherlands, two from Finland, and one from Germany have already returned to the estuary. This means that the only known foreign bird not to have been seen so far is one more from The Netherlands. It took me a long time to find the bird that frequented Coombe Hill and Ashleworth Ham during the late spring, but I eventually tracked it down to the roost at Wibdon Warth, just a few yards from where it had been ringed.
It is early days yet, but the results so far clearly show how site faithful the Curlews are, and how dependent they are on a relatively small feeding area. Even the foreign breeding birds are absent from the estuary for only a short time in the spring and early summer. Any change to this environment, such as the construction of a barrage, is going to affect them adversely. We must not take them for granted.