Resumen de What are different biometric measurements of avian body size actually measuring?
Tarsus, wing and culmen lengths are typical measurements obtained by ringers. Keel length has also been suggested for some species as a useful measurement. The usefulness of all these measurements is based on different assumptions. Keel and tarsus length are thought to measure bones, and thus are assumed to provide a good estimate of overall body size, while culmen and wing length are thoughf to measure the horny component (;. E. Ramphotheca and feathers respectively), which would therefore also reflect variation due to wear and tear: Here we present stepwise multiple regression analysis of tarsus, keel, wing and culmen lengths on their different bony and horny components. The analysis is based on a sample of 68 Serins Serinus serinus for which we measured both externa1 and bony (skeletal) components. Results show thaf externa1 keel length was a beffer predictor of bony keel length (r²=98%) than externa1 tarsus length was of tarsus bone length (r²=69%). Wing length was mainly influenced by third primay length (r²=87%) and only 4% of variance was additionally explained by adding carpometacarpus length. Culmen length was shown to be not closely related to premaxilla length (r²=25%), which suggests that it is mainly a measuremenf of the ramphotheca; however, this conclusion has to be taken with caution because of the high degree of potential error in culmen measurement. Our results support the assumptions previously stated for these measurements.
