A re-evaluation of morphological differences in the Karoo Thrush Turdus smithi–Olive Thrush Turdus olivaceus species complex
- Wilson, J W, Symes, C T, Brown, M, Bonnevie, Bo T, De Swardt, D H, Hanmer, D
- 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
- 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
Timing of moult and breeding in the Cape White-eye, Zosterops pallidus, from three different geographical regions in South Africa
- Hulley, Patrick E, Craig, Adrian J F K, Underhill, George D, Bonnevie, Bo T, Nuttall, R J, De Swardt, D H
- Authors: Hulley, Patrick E , Craig, Adrian J F K , Underhill, George D , Bonnevie, Bo T , Nuttall, R J , De Swardt, D H
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: article
- Identifier: http://hdl.handle.net/10962/465570 , vital:76621 , https://doi.org/10.1071/MU03055
- Description: Cape White-eyes are widespread in South Africa, occurring in different climatic regions. We analysed primary moult data for large samples of this species from three geographical regions. There were no apparent long-term changes in duration or timing of moult during the nine years that the Western Cape results were collected, but sites within this region had different mean starting dates for primary moult. The Eastern Cape and Free State birds began moult about a month later than those in the Western Cape. This correlated well with the earlier breeding season in the Western Cape, and there was no evidence of overlap between moult and breeding. Mean primary moult duration was not significantly different among the sites or regions, and may be a species-specific trait. There was no evidence of regular long-distance movements in this species.
- Full Text:
- Date Issued: 2004
- Authors: Hulley, Patrick E , Craig, Adrian J F K , Underhill, George D , Bonnevie, Bo T , Nuttall, R J , De Swardt, D H
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: article
- Identifier: http://hdl.handle.net/10962/465570 , vital:76621 , https://doi.org/10.1071/MU03055
- Description: Cape White-eyes are widespread in South Africa, occurring in different climatic regions. We analysed primary moult data for large samples of this species from three geographical regions. There were no apparent long-term changes in duration or timing of moult during the nine years that the Western Cape results were collected, but sites within this region had different mean starting dates for primary moult. The Eastern Cape and Free State birds began moult about a month later than those in the Western Cape. This correlated well with the earlier breeding season in the Western Cape, and there was no evidence of overlap between moult and breeding. Mean primary moult duration was not significantly different among the sites or regions, and may be a species-specific trait. There was no evidence of regular long-distance movements in this species.
- Full Text:
- Date Issued: 2004
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