A re-evaluation of morphological differences in the Karoo Thrush Turdus smithi–Olive Thrush Turdus olivaceus species complex
- Authors: Wilson, J W , Symes, C T , Brown, M , Bonnevie, Bo T , de Swardt, D H , Hanmer, D
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447680 , vital:74666 , https://doi.org/10.2989/OSTRICH.2009.80.3.7.970
- Description: There is confusion in the literature concerning the taxonomic status of the Turdus smithi—T. olivaceus species complex. Here we attempt to clarify morphological differences within this complex. In addition, we attempt to clarify identification of the respective taxa. Although mean measurements of morphometric features differed significantly between species and subspecies, these features are not useful in separating species or subspecies due to considerable overlap in measurements. Furthermore, there were often larger differences between subspecies of T. olivaceus (particularly the geographically isolated T. o. swynnertoni) than between T. olivaceus and T. smithi. We therefore suggest that further work investigates the elevation of T. o. swynnertoni to full species status. Plumage characteristics proved more useful in separating T. olivaceus and T. smithi in the field, except in regions where the distributions overlap (potential hybridisation zones). We highlight the importance of clarifying the delineation of separate species particularly with respect to bird census data (e.g. Southern African Bird Atlas Project 2) and studies related to these species.
- Full Text:
- Date Issued: 2009
Can eyeflecks be used to sex African Black Oystercatchers Haematopus moquini in the field?
- Authors: Kohler, Sophie , Bonnevie, Bo T , Dano, Stéphanie
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448070 , vital:74695 , https://doi.org/10.2989/OSTRICH.2009.80.2.8.835
- Description: Morphometric differences between males and females are a common feature among oystercatcher species (Hockey 1996), although breeding partners often appear similar when observed from a distance. Combinations of different biometric parameters such as bill size and shape, body mass, wing and tarsus lengths have been used to discriminate males and females in the field in European Oystercatchers Haematopus ostralegus (Zwarts et al. 1996), American Black Oystercatchers Haematopus bachmani (Guzzetti et al. 2008) and the three oystercatcher species present in New Zealand (Baker 1973). Sexual dimorphism also occurs in the African Black Oystercatcher Haematopus moquini, an endemic species living on the coasts of Namibia and South Africa. In this species, females tend to have longer and sharper bills than males (Hockey 1981, Hockey 2005).
- Full Text:
- Date Issued: 2009