PCA (Principal Component Analysis) application to differentiate hybrid and pure black-winged myna (Acridotheres melanopterus)

Abstract

Black-winged myna (Acridotheres melanopterus) is an endemic bird of Java and Bali that is currently critically endangered based on International Union of Conservation for Nature (IUCN) since 2010. Hybridization in captivity occurs between the Acridotheres melanopterus with other species of myna. It is difficult to distinguish hybrid and pure black-winged myna without thorough observation. The study was conducted to determine the differences between hybrid and pure black-winged myna based on the morphometric characteristics using Principal Component Analysis (PCA). The samples were selected using purposive sampling method at Cikananga Conservation Breeding Center located in Sukabumi, West Java in May 2017. The morphometric data were taken directly from 44 black-winged mynas with > = 2 years old. Data collection was done by measuring body length, body width, body circumference, span of wings and weight. The morphometric data were analyzed by PCA using the SPSS V.20 program. The results showed that body circumference and wing span were the morphometric factors which the most distinguish between them with eigenvalue of 0.943 and 0.811 respectively. In addition, the existence of morphological anomalies is also a sign that the black-winged mynas are hybrids.