Assessment of the incubation period for each sex of Turkish semiwild northern bald ibis (Geronticus eremita)

Abstract

The semiwild population of Northern Bald Ibises (Geronticus eremita) at Birecik, Turkey, are the final representatives of the Eastern population of the species in the Middle East, apart from a few captive birds in Turkish zoos. This study took place between 2012 and 2015. Breeding is highly synchronized among the colony and incubation behavior was monitored for multiple nests throughout the day. Differences were found when incubation duty period was examined according to sex. In 2013, the incubation period varied significantly between males and females (F = 71.059, P < 0.001). The female incubated eggs for 178.42 min per day on average, while the male incubated for 233.69 min per day on average. A significant difference in incubation was determined between males and females (F = 91.260, P < 0.001) in 2014. Females sat on eggs for 188.06 min on average, while males sat on eggs for 244.13 min on average. In 2015 the incubation period varied significantly by sex, similar to previous years (F = 79.871, P < 0.001). The female incubated for 159.66 min in average, while the male incubated for 223.07 min on average