The first visit to ring shearwaters on Old Lighthouse Island was made in 1952 when some Manx Shearwaters were ringed with numbered aluminium rings. Since then a continuous study has been made of this very special bird. It is a seabird which roams the whole Atlantic Ocean and only comes to land to breed, starting at three or four years old. Gulls find the shearwater very tasty and to avoid being caught, the shearwaters only come to their breeding islands in the middle of the night. They nest in commandeered rabbit burrows and seem to have no difficulty finding them in the dark.
Members of the observatory use torches to find the shearwaters on the ground going into or out of their burrows and have ringed almost all of the breeding adults already. Much of the catching work now involves retrapping and recording the presence of these birds as they visit their nests. Most of the birds are retrapped and checked on average once every five to ten years.
George Thomson was on the observatory for a week up to the 22nd June, 2003. Bright nights meant little shearwater activity, but on his last night he caught 42, of which 33 were retrapped birds originally ringed on Copeland. Many of the birds were ringed in the last few years as chicks, now back after their childhood wanderings over the oceans, and looking for a burrow and a mate. He came across two fighting birds which he had to separate. One was bleeding a lot and took quite some time to recover.
However, one of the retrapped birds was EJ 14240, caught in the Cliff sub-colony. Next day when the field notes were being entered in the shearwater record books, he discovered that one of the birds was really old. On checking in the shearwater book, he discovered that it had originally been ringed in 1953, on an exploratory expedition just one year before the observatory was established. This bird has been alive and well for 49 years, 11 months and 4 days since it was originally ringed, i.e., almost 50 years. This beats the previous longevity record held by Bardsey Bird Observatory by 4 years. As the bird was ringed in July as an adult, this means that the bird was born in 1952 or earlier. Indeed most likely it was earlier. Most young birds do not return to the colony until they are 3 or 4 years old, so this bird is older than a considerable number of our members! It must be older than our ringing secretary and is close to twice as old as our shearwater secretary! Since there is no way of knowing its exact age, it could be older than any of the committee members and office bearers, though hardly our president!
Its current ring number EJ14240 is actually its fifth ring. Over the years, its various rings have become worn and had to be replaced in turn. Luckily its last ring, put on in 1983, is made of very long-lasting material. Its first ring number was AT14414. During its 50 years of carrying a ring, it has been retrapped 15 times, the last one being in 1989. Only 25 shearwaters were ringed in 1953 and it is really remarkable that one of them is still alive and well.
The shearwater study is one of the most important parts of the observatory's activities. Though this is an obvious high point in the study, the mass of basic information gathered slowly and with considerable effort by so many voluntary ringers over the years is of the greatest conservation importance in understanding the population dynamics of this species. Work is progressing on the analysis of all this data and scientific papers will be published presently on the results of our study.
The previous longevity record for Manx Shearwater was set two years ago by Bardsey Bird Observatory, a sister organisation in West Wales where a similar long term study of the species has been taking place. Their record breaker was 45 years ringed and beat the oldest Copeland one at the time by 5 years. The Bardsey bird was caught again earlier this year at almost 46 years of ringed age. (It has also been handled again in 2004). Bardsey has an advantage over Copeland in that they know the precise burrow occupied by their oldest bird, while we do not. If they can catch their bird in the second half of 2007, they will be able to claim back the record for the longest ringed bird unless we have managed to catch our old bird again in the meantime. Hopefully, we will identify its burrow next time. Each shearwater field sheet will have its number at the top, and the two birds that are possibly still alive from 1952.
Not only is this Copeland bird the oldest known Manx Shearwater, it is the oldest known ringed wild bird of any species in the British Ringing Scheme. Apparently, as far as can be ascertained at the moment, it is even the oldest proved wild bird in the northern hemisphere! The previous best was a Laysan Albatross which has not been heard of since it was 46 years old. In the southern hemisphere, the longest lived ringed bird was a Royal Albatross at 52 years, but it also is believed to be dead now.
| © Copeland Bird Observatory, 2004 |