Determination of the relationship between beak length and body weight of juvenile northern bald ibis ( Geronticus eremita) and estimating body weight from beak length

Abstract

The aim of the study is to measure the body weight and beak measurements of the juvenile bald ibis birds breeding in Tiirkiye and try to find out whether there is a comparative relationship between them and compare them with the measurements in the other studies. In this direction, beak measurements and body weights of total 460 bald ibis chicks, including 197 male chicks and 263 female chicks, were determined in an 11 -year period from 2012 to 2022. Average upper beak length was found 15.68 cm, lower beak length was 11.34 cm and average body weight was 1.11 kg in male bald ibis juveniles. Average upper beak length was found to be 15.08 cm, the average lower beak length was 10.84 cm and the average body weight was 1.07 kg in female bald ibis juveniles. A positive and moderate significant relationship was found between upper beak length and body weight (P<0.001). It was determined that the average body weight of male bald ibis juveniles was higher than the body weight of female bald ibis juveniles (P<0.001). Body weight variation could be explained by using only upper beak and lower beak measurement in 26% and 29% respectively. No significant variation was observed in the live weight of bald ibis chicks over the years.