Spend any time watching garden birds and you’ll soon realise that there is a great deal going on in your average garden. However, what you see is merely scratching the surface of what is really happening and much remains hidden from view because, to our eyes, most individuals of a given species look alike. The handful of Blue Tits that you see daily at your hanging feeders may, in reality, be many dozens of different individuals, which use your garden on a daily, weekly or seasonal basis.
As a trained and licensed bird ringer, I have been able to appreciate the numbers of individuals that may make regular use of a garden feeding station. Even so, I still need to catch the birds regularly to discover which individuals are still popping in for a feed. One way in which it is possible to build up a more complete picture of the lives of individual birds is through colour ringing, a technique by which licensed bird ringers fit birds with unique combinations of coloured rings. Once fitted with such rings a bird can be identified as an individual without the need to recapture it.
Colour ringing is best used for targeted projects, seeking to look in detail at a population of birds within a given area. This might be at the scale of the Blackbirds using a series of gardens in Holt (as is the case for one Norfolk-based project) or it might be at the scale of Black-tailed Godwits moving between Iceland and various sites in Britain and continental Europe (research being carried out by staff at UEA).
Looking in detail at a particular population invariably adds to our knowledge, revealing more about behaviour, ecology and survival. Colour ringing of birds has, for example, been used to look at breeding behaviour, highlighting which birds hold which territories and with whom they breed. At the same time it can change your perception of the numbers of birds that make up your ‘local’ population. Colour ringing of Great Spotted Woodpeckers at Croxton, just on the edge of Thetford Forest, has been taking place over the past six years. Some 63 different individuals have been colour ringed at the feeding station in this time and resightings by the site’s owner have revealed much about how these local birds are using the feeders. One female visited the feeders almost every day for five years, while another was a regular visitor for three years, only to disappear and then return two years later.
Colour ringing also enables members of the public to report any colour-ringed birds that they may see. Simply contact the British Trust for Ornithology’s ringing scheme (www.ring.ac) and let them know what you have seen and where.