A small metal band is placed on one of the front wings. Juvenile or adult. An examination of the wing gives an indication of age. Sex is next. Male of female.
Reproductive organs are quite obvious.
Length of the forearm is measured in millimetres. Sometimes other measurements are recorded too. The bat is then weighed by placing the bat inside a bag. The bag is then attached to a spring weight measure and the weight is recorded in grams. The bat is released.