Summarising biometrics from the SAFRING database for southern African birds

Biometrics form a key characteristic of a species. Here, we provide a summary of biometrics held by the South African Bird Ringing Scheme (SAFRING), which was initiated in 1948, including measures of mass and lengths of the tarsus, head, culmen, tail and wing. We include all species in southern Africa for which there was sufficient data. Accordingly, we present biometric data for 674 of the 904 southern African bird species. We also investigated whether there were sex-specific differences for each species, and provide summaries for species where values significantly differed between the sexes. We found 376 species with significant sex-specific differences for at least one measure (e.g. mass). Although SAFRING holds data entries for many ringed individuals, a sizeable proportion of the entries was not useable as biometric data. Therefore, in this article, we aim to: 1) present a complete, standardised reference of summarised biometric data for the birds of southern Africa; 2) provide ringers with benchmark values that could guide data-capturing; 3) identify data-deficient species; and 4) highlight the importance of collecting and capturing biometric data carefully and consistently.