Butt-end and lock-on aluminum band loss and wear were studied in the White Stork (Ciconia ciconia) banded in Spain. The risk of loss of butt-end bands increased from 0% to 85% in bands of 0 to 12 years. However, no loss occurred when storks were banded on the tibia rather than in the tarsus. Lock-on metal bands showed a low band loss rate throughout. The results indicated that band loss was mainly caused by the band opening, probably because of frequent contact with mud and water on the tarsus. Aluminum bands should be completely discarded to avoid important biases in analyses of population dynamics, dispersal and survival of storks and other groups. This is currently already done in many banding schemes, but should be applied more generally worldwide.