During the summer the Ospreys at Rutland Water can easily be identified by the coloured Darvic rings on their legs. For any one sitting in Waderscrape hide earlier this year it was obvious which bird was the male; he had 5R inscribed in white digits on a green ring on his right leg. Besides the obvious difference in plumage between the chicks and the adults, the youngsters were easy to spot because of their bright blue rings with their individual numbers, 22, 32 and 52.
Every year the chicks are ringed when they are six weeks old and they are each given their coloured Darvic ring and a silver BTO ring.
The birds are given a silver BTO ring as part of a nationwide ringing scheme that is run by the British Trust for Ornithology. Over 2,600 trained, volunteer ringers ring over 900,000 birds in Britain and Ireland each year. Each ring has a unique eight digit number and when a bird is ringed it is aged, sexed, weighed and measured and all the records are stored in the Natural History Museum in London. Ringing generates information on the survival, productivity and movements of birds, helping us to understand why populations are changing and therefore it is vital for conservation.
On sunday some of the members of the Rutland Water Ringing Group spent the morning at Lyndon Nature Reserve. The group, led by Gary Barker, had a successful session with over 75 birds. They ringed many species including, Blue Tit, Great Tit, Blackbird, Coal Tit, Wren, Reed Bunting, Treecreeper, Long-Tailed Tit, Chaffinch, Greenfinch, Dunnock, Song Thrush, Redwing, Marsh Tit, Robin and Bullfinch. The highlights of the day were two Green Woodpeckers, a male and a female, and a juvenile male Sparrowhawk.
Although recent advances in satellite tracking have greatly enhanced our understanding of Osprey migration, prior to the development of the new high-tech trackers we had to rely on ringing recoveries to build up a picture of where Ospreys from the UK spend the winter. It is more than one hundred years since the first bird was ringed in the UK, but ringing still has a vital role to play. This was demonstrated recently when we received news from the BTO about one of the nine young Ospreys that fledged from Rutland in 2009.
Those of you who have followed the progress of the project on the website this year will know that four of the 2009 birds made it back to Rutland Water this summer. One of the five birds who we have not seen since that autumn was 05(09) and, sadly, we now know why.
05, a male, was one of three chicks that fledged from the Site O nest (on private land near Rutland Water) in 2009.
He migrated in early September and we now know he wintered 1850km to the south in Puerto Real, near Cadiz in southern Spain. We know this because, sadly, on 3rd March 2010 he was found dead close to Puerto Real.
The BTO ringing recovery states that he was ‘found with injury’. Bearing in mind that there are a large number of fish farms in that part of southern Spain, there seems every chance that 05 died of an injury sustained after flying into a net over one of these fish farms. Whilst it is sad that the young male did not survive, it is interesting that, like an increasing number of Ospreys from the UK he was wintering in Spain rather than West Africa. So although 05 did not survive, his rings have contributed to our understanding of Osprey wintering behaviour.