Combination of :
* yellow ring (on left or right tibia).
* c-ring above or below metal ring (on right tarsus).
* 2 c-rings (on left tarsus).
note 1 : ringed birds are adult.
note 2 : used colours are : yellow, white, black, red, blue, orange, green, light-blue.
note 3 : metal ring is part of the combination.
note 4 :