Individual traits of gulls removed by shooting or by the use of birds of prey.

Removed birds were examined to determine the sex and age of the individual, the individual nutritional state, assessed from fat layers and muscle condition, and any sign of infection, malformation or disease. We identified four age classes by plumage features: juveniles (from 0 to 1 year old), 2 years old (from 1 to 2 years old), 3 years old (from 2 to 3 years old), and adults (>3 years old). We determined three levels of body condition: normal, low and high, depending on the layers of muscle mass). Veterinarians determined if the illness detected was either severe or mild.