Morphometric sex determination of Milky and Painted storks in captivity

Abstract

Logistic regression was applied to develop a morphometric sexing method of two closely related stork species that were previously sexed through amplification of the CHD gene. Tarsus length (TL) and bill length (BL) measurements were recorded from captive populations of adult Milky Stork (Mycteria cinerea) (n = 60) and Painted Stork (Mycteria leucocephala) (n = 58) at Zoo Negara Malaysia. Despite having monomorphic plumages, both stork species exhibited normal sexual size dimorphism in which males were significantly larger than females in the tested variables. Based on logistic regression analysis, BL correctly classified the sex of sampled individuals from Painted and Milky stork with an overall predicted accuracy of 94.8 and 90.0%, respectively. However, TL measurements generated a lower predicted accuracy level of 86.2% and a same accuracy level of 90% on the sex classification of individuals from Painted and Milky stork, respectively. By comparing the measurements of both species, only the average BL measurements of the Milky storks were significantly lower than that of Painted storks (t-test, P80.001). The logistic regression equation in this study may serve as a simple and more practical option for sexing Milky and Painted storks for their breeding and conservation programmes.

Sex discrimination in the Savi’s Warbler (Locustella luscinioides) using morphometric traits

“…It has previously been used in some monomorphic bird species (e.g. Ellrich et al 2010, Ong et al 2011.…”

Analysis of Reproductive Traits in the Painted Stork (Mycteria leucocephala)

“…Also their naturally preferred food is a limiting factor (Urfi, 2011b). The painted stork is found in the wild of Asia, mainly in India and Sri Lanka (Ong et al, 2012). According to the International Union for Conservation of Nature (IUCN) classification, the painted stork belongs to the category of NT -Nearly Threatened species (BirdLife International, 2016).…”