Mountain Wheatear Myrmecocichla monticola: comparative biometrics, moult and breeding data, and criteria for the determination of age and sex

Abstract

In this article we present measurement and moult data from over 160 Mountain Wheatear (Myrmecocichla monticola) of the subspecies atmorii (Tristram, 1869) ringed in Namibia, as well as two individuals of the adjacent northerly subspecies M. m. albipileata (Bocage, 1867) from Angola, and discuss our findings from these subspecies. We gathered nesting, breeding and moulting records for Namibia from published literature and photographic records, and compared our observations of the moult process and our records of active brood patches with breeding records, gathered by Brown et al. (2017), to gain insight into the timeline of physical processes. On the basis of photographs, we describe the nestling and compare juvenile and immature plumage and other features which help to distinguish these age groups. We add notes on the overall numbers observed in the last fifteen years and notes on recaptures, site fidelity and parasites. We discuss the white covert-patch as an indicator of age and document undescribed plumage details such as signs of a second-year plumage, spots on the coverts of first-year birds, white supercilium in grey males, the occurrence of grey or black greater coverts in grey males and features from both sexes in one plumage. This article is intended to supplement published data and encourage further research and discussion.