Notes on African Rock Pipit Anthus crenatus biometrics

Abstract

African Rock Pipits Anthus crenatus occur in mountainous terrain with steep slopes, and as a result are not easily captured. This is borne out by the South African Bird Ringing Unit (SAFRING) data, which lists fewer than 20 individuals of this species ever having been caught and ringed. As a result of this, there are also limited biometric data available for this species. In this paper, I collated biometric data from ringed birds (n = 12) as well as museum study skins housed in the National Museum, Bloemfontein (n = 22), Durban Natural Science Museum (n = 2) and East London Museum (n = 17). Biometric data were taken from sexes and included culmen, tarsus, hind claw, wing and tail lengths and body mass. Male African Rock Pipits were significantly longer-winged and had longer tails than females (wing: t = 5.239; df = 50; P < 0.05; tail: t = 2.310; df = 50; P < 0.05). Mean wing lengths were 86.5 mm for males and 82.7 mm for females, while tail lengths were 67.0 mm for males and 64.3 mm for females. Hind claw lengths also differed significantly between the sexes (t = -2.227; df = 29; P < 0.05), although this metric is probably biased owing to the small female sample size. No significant differences were evident in culmen and tarsus lengths or body mass between the sexes. The only previous study that reported the morphometrics of this species used a much smaller sample size than the present study, and only reported details for culmen, wing and tail lengths and body mass. This study represents the first detailed biometric dataset for African Rock Pipits based on limited bird ringing data and supplementary biometric data obtained from museum study skins. The value of museum specimens to obtain biometric data is again highlighted.