It was reported that the “species’ huge range, current rarity, variable abundance, cryptic habits, mobility, along with difficulty of logistics and lack of resources may present insurmountable obstacles to its effective study” (Marsden et al. 2013). McGowan (2001) assessed different methodologies for surveying P. erithacus populations and concluded that due to the difficulties involved with each, alternative methods of assessing population trends and the impacts of trade on this species are more appropriate than population estimates.