at Blashford Lakes a number of bird ringing projects are carried out by specially trained volunteers under the auspices of the British Trust for Ornithology (BTO). They have been overseeing bird ringing for over 100 years now and almost all that we know about the migration, longevity and survival of our birds has been found out using the results. These are all vital to understanding how we can look after the birds we have got and try to restore ones we are losing or have lost.
At the simplest an individually marked metal ring is attached to the leg of a caught bird, it is examined to establish species, age, sex and condition and then released. Most of these birds are never reported again, but with many thousands caught the percentage found was still enough to establish something of the remarkable journeys they undertake. We have probably all heard that our summering Swallow spend the winter in southern Africa, but who would have guessed that the Blackcap that winters in your garden is not the one that was there in the summer, they are down by the Mediterranean, instead it is perhaps from SE Germany.
Today it is possible to use additional techniques such as colour-rings, radio and satellite tags, but these are expensive especially for smaller birds as they need to be very light indeed. Some species are rare and hide very well, so it is difficult to catch them in the first place and if you do they are very unlikely to ever be seen again and small sample sizes mean you are always unsure how typical the data collected will be. To gain a fuller picture of their lives techniques such as stable isotope analysis and DNA sampling can assist, if you are interested do a search, there is a lot of fascinating information out there..
Despite all these high tech and sometimes very costly techniques coming into the picture much of what we are learning is still coming form the traditional ringing, largely thanks to the shear size of the samples it can achieve. The other important role of traditional ringing is to train new recruits, it takes typically a year or two to complete basic training and many more to become expert or specialise in particular techniques or species.
At Blashford Lakes we have a colour-ringing project for Black-headed Gulls, a nestbox project and a Constant Effort Site (CES) as well as some winter ringing with training opportunities. Recently one of the regular sessions turned up a rarer than usual visitor, a Siberian Chiffchaff. A lot of Common Chiffchaff pass through the UK in the autumn, some stay the winter, but many more head on down to the Mediterranean. Chiffchaff breed right across Europe and into Asia, although all the same species, the birds get paler and greyer the further east you go and these birds also call differently, and it was one of these eastern birds that turned up. The pictures below show the difference in appearance between a “typical” Chiffchaff and the Siberian visitor.
This autumn seems to have been a good one for reports of these Siberian Chiffchaffs, maybe just a chance increase in sightings or perhaps indications of a change in migration pattern as seems to be happening with a number of other Siberian nesting species. Only time will tell and who knows maybe this bird will be reported again and add to our understanding of how migration is changing, or not.