Combination of :
* orange (and later green) ring with a black one alpha code (letter 'X') and metal ring (on left leg)
* combination of 3 c-rings (on right leg).
note 1 : metal ring is part of the combination.
note 2 : when some 1000-1500 birds are ringed , the position of orange ring and combination of 3 c-rings, will be switched : left <-> right.
White ring with a black three numeric code (on left tarsus) and metal ring (on right tarsus).
note 1 : birds ringed during breeding and during winter in SW Sweden. Breeding birds might migrate to SW Europe while wintering birds may also show up north of the ringing site.