Bird watching and estimation of bird diversity – not always corresponding: a reply to Hogg and Vande weghe

Abstract

Some occurrences of rare or unusual bird species reported by us in a previous paper (Ostrich 86(3): 267–276, 2015) are considered to be doubtful by Hogg and Vande weghe (Ostrich 88(1): 83–88, 2017). We believe that some of the problems raised are taxonomic. The main objective of our study was to obtain reliable estimates of bird diversity. The ‘judgement’ made by Hogg and Vande weghe of the appropriateness of specific observations in our study is based on a probabilistic view based on observations mainly made by the ‘public along roads’, which is not the ideal sampling method for estimation of bird diversity due to its sampling biases. Effort needed for an observation to qualify while bird watching is not the same as when studying overall bird diversity.