SHORT REPORT On reading colour rings

The use of engraved plastic leg rings (Ogilvie 1972) has proved an extremely useful tool for long-term studies of individual birds within populations. Several studies have examined the longevity of marks (eg Rees et al 1990) and the colour fastness of certain materials (eg Lindsey et al 1995). In addition, Kania (2001) asked observers to read letters on metal rings used on White Stork Ciconia ciconia using binoculars. Inexperienced observers misread up to 27 % of letters, whereas trained observers misread up to 8 % of letters. On reading numbered neck collars on Canada Geese Branta canadensis, casual observers made 23 times more mistakes than trained professionals (Raveling et al 1990). However, as far as we are aware, there is little information on whether letters on certain colour combinations are easier to read than others. We examined this using a simple experimental approach using two different telescopes, sets of engraved plastic rings with different colour combinations and several observers. Each ‘ring ’ consisted of a plastic strip c 38 mm x 105 mm, the same dimensions as commonly used on Whooper Swan Cygnus cygnus colour rings. Three engraved letters, each 20 mm tall, 10 mm wide and with a 2 mm cut width were repeated three times on each ring. Each set of rings comprised five commonly used colour combinations; dark blue with white letters, orange/black, pale green/black, white/black and yellow/black. Each ring set, therefore, comprised 15 different letters. The letters were randomly chosen from 15 letters normally used on engraved ring