“…Although the four cuckoo species could occur in the same area, specific habitat preferences may differ among species (Lee et al, 2014). For example, both the oriental cuckoo and Indian cuckoo appear to prefer mountainous areas, whereas the common cuckoo and the lesser cuckoo have broader habitat preferences, including open areas such as grasslands, reedbeds, and mountains (del Hoyo et al, 1997;Payne and Sorensen, 2005;Allen et al, 2012;Erritzøe et al, 2012;Lee et al, 2014;Yun et al, 2020). Therefore, these differences in habitat preferences may alternatively generate variations in their morphology (Linsdale, 1938;Hamilton, 1961;Norberg, 1979Norberg, , 1990.…”