Leader:Alan Feest
With poor weather conditions overnight, it was decided there would be no bird ringing at Chew Valley Ringing Station (CVRS) the next morning. The welfare of the birds was, as always, paramount.
Despite this disappointment, Alan gave us a most interesting morning, explaining the history of bird ringing and why birds are ringed as well as how.
Bird ringing was initiated by a Dane at the turn of the 19th century. The Germans and British followed. Currently Britain has around 3,000 ringers who ring close to one million birds each year. A vast number of birds need to be ringed as no more than 1% of ringed birds are recovered.
For many years it was a total mystery where certain birds went during the winter. The first recovery of a ringed swallow in South Africa was met with total disbelief.
Understanding bird population dynamics is of the utmost importance. The CVRS’s contribution is to run a Constant Effort Site. The same mist nets are set in the same places for a set amount of time each year. This powerful methodology is yielding a lot of often worrying information. More data is gathered by ringing chicks in nest boxes when they are old enough.
The techniques for monitoring the migration routes of various species of birds is forever increasing as the technology improves. Nowadays GIS (Geographic Information Systems) technology can track species like the cuckoo on long and varied journeys.
At the Chew Valley Ringing Station there is surprisingly little equipment needed: ringing pliers, rulers, scales, reference books, computer, bird bags/boxes, hand lens, and good eyesight along with the expensive mist nets and, sometimes, traps. Computer are necessary nowadays so all records can be centrally recorded, resulting in more extensive investigations.
To handle the birds, ringers need to be licensed. There are three levels: trainee, experienced but supervised, then finally experienced, who can act as trainers.
The three basic processes are:
1) Extracting the birds from the nets or traps.
2) Putting on the ring
3) Ageing and sexing the bird.
Due to HPAI (Highly Pathogenic Avian Influenza) birds like ducks and swans are not currently being ringed at Chew. HPAI has mainly been confined to water birds. Precautions such as washing hands and the bird bags are carried out regulalrly.
The Chew Valley Ringing Station is a wonderful resource that gets excellent support from Bristol Water. The lake was opened in 1956 and immediately became a very successful bird watching site. Its potential as a ringing site was quickly recognised and it is now considered one of the most important sites for ringing in Britain.
Afterwards some of the group went to Herriot’s Bridge where they were treated to sights of Whimbrel, Whinchat, Black Tern and Hobby.
Andrew Harrison
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