Abstract
For the hooded crow (n = 537), the ratio between body weight and bill height was a better indicator of the amount of abdominal fat than either body weight alone, or the ratio of body weight to other size dimensions, e.g., wing, tail, tarsus or bill lengths. The ratio of body weight to bill height, in particular, is recommended if either the age or sex, or both, of a bird are unknown, and the possible reason for this is discussed.