Yellow ring with a black 3 alpha-numeric code [starting letter 'A' or 'B' followed by two numbers] and metal ring.
note 1 : birds ringed in Serbia, end June 2013.
note 2 : used codes are all starting with "A" or "B", followed by two numbers.
note 3 : the coming years other letters will be used. Details will follow.
note 3 : note that a 'similar-close' project with as starting number '4' followed by two letters- runs in Spain. Do read carefully the codes !!
note 4 :