Study Group

 
  

 
 
 

 
 

Colour Ringing

Ring Ouzel Colour Ringing Sceme

Bird ringing allows the study of individual birds, giving us information about how long they survive and their movements. In most cases, this information is gained through retrapping a bird previously fitted with a metal ring. As there are not many re-traps of adult Ring Ouzels from which to glean this information, another tool is required. The addition of ‘extra’ colour rings to birds, fitted in unique combination allows the bird to be identified as an individual in the field without the need for being re-trapped.

The Ring Ouzel colour ringing scheme was initiated in 1993, with the aim of increasing the knowledge about Ring Ouzel movements and survival.

The scheme uses coloured rings, 7mm in depth, made from Darvic PVC plastic. This material is well suited for colour ringing as it is a strong lightweight material which retains colour well. Seven colours are regularly employed by the scheme: red, orange, yellow, dark green, light green, dark blue and white. These colours have been carefully selected as they are most readily identifiable at a distance in the field against both the environment and the birds’ legs. In years when lots of birds have been ringed and more combinations are required, the colour black is added to the scheme. However, black is a more difficult colour to see against the dark legs of the birds.

On the leg where the BTO metal ring is fitted (either the right or the left leg depending on the exact combination being fitted), a year colour is fitted either above or below the metal ring. The year colour indicates the year in which the bird was first caught (not its age); colours used in recent years are in the table below:

Year
Colour
2003
Dark Green
2004
Light Green
2005
Dark Blue
2006
White
2007
Red
2008
Orange
2009
Yellow

On the other leg, an additional two rings, 7mm in depth are fitted if the birds are caught in either Glen Esk, Tayside Region or Glen Clunie, Grampian Region, north east Scotland. This metal, year colour and two colour combinations gives a total of 196 unique combinations available each year. If there is demand for more combinations then unused combinations from previous years will also be used, or the less identifiable black colour added to the scheme. Birds which were ringed in Bowlands, Yorkshire, used three 5mm in depth colour rings and this system was previously used in Glen Clunie before they switched to the two ring system in 2003. The three-colour ring system has the advantage of having more unique combinations; however it is more difficult to read accurately in the field. Rings may be potentially missed, allowing confusion between the individuals fitted with two rings, and those fitted with three.

photo courtesy of Sonja Ludwig

The above ring combination is metal/light green (RIGHT LEG), orange/blue (LEFT LEG)

The first Ring Ouzel to be fitted with colour rings was ringed in April 1993. Since then the scheme has grown and to date, over 3,250 bird have been fitted with colour rings. Most of the birds ringed have been ringed as pulli in the nest as fully grown Ring Ouzels are notoriously difficult to catch using mist netss.

The colour ringing has been of great benefit, allowing return rates to natal sites to be calculated. Some individuals have been observed returning to and breeding in the same area each year. Other birds have moved between study sites, for example between Glen Clunie and Glen Esk. The success of the colour-ringing scheme could be extended by systematic searches during the breeding season for colour ringed birds, as at present most of the re-sightings are from the few study sites where Ring Ouzels are intensively studied. The lack of re-sightings from the public is probably a result of the species’ ‘shy’ nature and preference for upland habitats with low inhabitation. When any birds are reported, every effort is made to identify the bird seen and give the finder information about the bird’s origin. Sometimes there are problems with reading the combinations of rings as colours can be miss-identified and on rare occasions rings may be missing; in these cases the exact bird may not be identifiable. Despite these difficulties, birds have been re-sighted both within the UK and from much further away from their breeding grounds. Birds have been seen on migratory stopovers in the French Pyrenees and on their wintering grounds in Morocco. One British ringed chick has even been reported in Scandinavia! This has greatly added to our knowledge of the species wintering range and migration routes.

If you would like further information on colour ringing Ring Ouzels, or have seen a colour-ringed individual, please contact the scheme’s coordinator, David Arthur either via e-mail davidarthur882@btinternet.com or telephone 01241 853356.

16 January 2010

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