Wing-moult and seasonal occurrence of sunbirds (Nectariniidae) captured at four sites in the Eastern Cape, South Africa
- Bonnevie, Bo T, Craig, Adrian J F K, Hulley, Patrick E, Schultz, Albert, Tree, Anthony J
- Authors: Bonnevie, Bo T , Craig, Adrian J F K , Hulley, Patrick E , Schultz, Albert , Tree, Anthony J
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449607 , vital:74833 , https://doi.org/10.2989/00306525.2022.2075482
- Description: Ringing activity in the Eastern Cape province, South Africa, spanned 30 years, with three sites active concurrently over a 14-year period, and three sites over a 6-year period. In total, in the course of 714 ringing days, in all months, we handled 1 207 Amethyst Sunbirds, 708 Southern Double-collared Sunbirds, 707 Greater Double-collared Sunbirds, 381 Grey Sunbirds, 121 Malachite Sunbirds and 140 Collared Sunbirds. Although individuals of all six species were recaptured more than five years after ringing, and despite evidence of the seasonal passage of sunbirds at two sites near the Indian Ocean coast, no birds were recaptured away from the original ringing site.
- Full Text:
- Date Issued: 2023
- Authors: Bonnevie, Bo T , Craig, Adrian J F K , Hulley, Patrick E , Schultz, Albert , Tree, Anthony J
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449607 , vital:74833 , https://doi.org/10.2989/00306525.2022.2075482
- Description: Ringing activity in the Eastern Cape province, South Africa, spanned 30 years, with three sites active concurrently over a 14-year period, and three sites over a 6-year period. In total, in the course of 714 ringing days, in all months, we handled 1 207 Amethyst Sunbirds, 708 Southern Double-collared Sunbirds, 707 Greater Double-collared Sunbirds, 381 Grey Sunbirds, 121 Malachite Sunbirds and 140 Collared Sunbirds. Although individuals of all six species were recaptured more than five years after ringing, and despite evidence of the seasonal passage of sunbirds at two sites near the Indian Ocean coast, no birds were recaptured away from the original ringing site.
- Full Text:
- Date Issued: 2023
A song for the South: also defining birdsong in global terms
- Bonnevie, Bo T, Craig, Adrian J F K
- Authors: Bonnevie, Bo T , Craig, Adrian J F K
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448759 , vital:74758 , https://doi.org/10.1111/ibi.12627
- Description: The article presents information on the importance of birdsongs, highlighting the structured vocalization required for mate attraction and defending of territory by male birds. Topics include the variations of themes in birdsongs during intraspecific communication, song acquisitions by the songbirds, and the impact of song learning by birds.
- Full Text:
- Date Issued: 2018
- Authors: Bonnevie, Bo T , Craig, Adrian J F K
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448759 , vital:74758 , https://doi.org/10.1111/ibi.12627
- Description: The article presents information on the importance of birdsongs, highlighting the structured vocalization required for mate attraction and defending of territory by male birds. Topics include the variations of themes in birdsongs during intraspecific communication, song acquisitions by the songbirds, and the impact of song learning by birds.
- Full Text:
- Date Issued: 2018
The timing of moult in males and females of the monomorphic Pale-winged Starling Onychognathus nabouroup
- Craig, Adrian J F K, Bonnevie, Bo T, Hausberger, Martine, Henry, Laurence
- Authors: Craig, Adrian J F K , Bonnevie, Bo T , Hausberger, Martine , Henry, Laurence
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443805 , vital:74155 , https://hdl.handle.net/10520/EJC177689
- Description: Pale-winged Starlings Onychognathus nabouroup inhabit the arid western interior of southern Africa and moult-breeding overlap may occur. We collected field data in two successive years on the moult of individual birds, whose sex was confirmed by genetic techniques. Small samples revealed a non-significant tendency for the moult of females in the early stages of wing moult to be more advanced than that of males in both years, but also clear evidence that the starting date of moult differed in the two years. In this species the moult schedule may thus be variable at both the individual and the population levels.
- Full Text:
- Date Issued: 2015
- Authors: Craig, Adrian J F K , Bonnevie, Bo T , Hausberger, Martine , Henry, Laurence
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443805 , vital:74155 , https://hdl.handle.net/10520/EJC177689
- Description: Pale-winged Starlings Onychognathus nabouroup inhabit the arid western interior of southern Africa and moult-breeding overlap may occur. We collected field data in two successive years on the moult of individual birds, whose sex was confirmed by genetic techniques. Small samples revealed a non-significant tendency for the moult of females in the early stages of wing moult to be more advanced than that of males in both years, but also clear evidence that the starting date of moult differed in the two years. In this species the moult schedule may thus be variable at both the individual and the population levels.
- Full Text:
- Date Issued: 2015
Primary wing-moult and site fidelity in South African mousebirds (Coliidae)
- Craig, Adrian J F K, Bonnevie, Bo T, Hulley, Patrick E, Underhill, George D
- Authors: Craig, Adrian J F K , Bonnevie, Bo T , Hulley, Patrick E , Underhill, George D
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449474 , vital:74824 , https://doi.org/10.2989/00306525.2014.931310
- Description: Based on large samples of birds mist-netted in the Eastern Cape and the Western Cape, moult of the primary remiges in both Speckled Mousebirds Colius striatus and Red-faced Mousebirds Urocolius indicus occurred throughout the year with no regional or seasonal patterns evident. The same picture emerged for the White-backed Mousebird Colius colius in the Western Cape. This aseasonality of wing-moult for all three species in South Africa was further supported by the full data set of moult records available in the Safring database. We were thus unable to use the Underhill–Zucchini model to estimate the moult parameters for these species, but an extended moult period seems likely. Recapture data for the Eastern Cape strongly suggest that Speckled Mousebirds are resident or revisit sites frequently, whereas this is not the case for Red-faced Mousebirds.
- Full Text:
- Date Issued: 2014
- Authors: Craig, Adrian J F K , Bonnevie, Bo T , Hulley, Patrick E , Underhill, George D
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449474 , vital:74824 , https://doi.org/10.2989/00306525.2014.931310
- Description: Based on large samples of birds mist-netted in the Eastern Cape and the Western Cape, moult of the primary remiges in both Speckled Mousebirds Colius striatus and Red-faced Mousebirds Urocolius indicus occurred throughout the year with no regional or seasonal patterns evident. The same picture emerged for the White-backed Mousebird Colius colius in the Western Cape. This aseasonality of wing-moult for all three species in South Africa was further supported by the full data set of moult records available in the Safring database. We were thus unable to use the Underhill–Zucchini model to estimate the moult parameters for these species, but an extended moult period seems likely. Recapture data for the Eastern Cape strongly suggest that Speckled Mousebirds are resident or revisit sites frequently, whereas this is not the case for Red-faced Mousebirds.
- Full Text:
- Date Issued: 2014
Variations in moult, morphology, movement and survival rates of the Sombre Greenbul Andropadus importunus within southern Africa
- Authors: Bonnevie, Bo T
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448368 , vital:74725 , https://doi.org/10.2989/00306525.2014.902403
- Description: Ringing data from the South African bird ringing unit, SAFRING, were analysed to explore variations and trends in population parameters of the Sombre Greenbul Andropadus importunus in southern Africa. Adult and juvenile body mass increased southwards, whereas the relative sizes of wings and bills decreased southwards. Recapture and recovery data indicated that adults have very high site fidelity and suggested that juvenile dispersal is limited. The annual survival rate of adults was on average more than twice that of juveniles and there was little regional variation within either age group. The onset of primary wing moult became progressively later northwards, but the duration of moult did not vary significantly with latitude. Juveniles started their first normally descendent wing moult sequence about one month after adults.
- Full Text:
- Date Issued: 2014
- Authors: Bonnevie, Bo T
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448368 , vital:74725 , https://doi.org/10.2989/00306525.2014.902403
- Description: Ringing data from the South African bird ringing unit, SAFRING, were analysed to explore variations and trends in population parameters of the Sombre Greenbul Andropadus importunus in southern Africa. Adult and juvenile body mass increased southwards, whereas the relative sizes of wings and bills decreased southwards. Recapture and recovery data indicated that adults have very high site fidelity and suggested that juvenile dispersal is limited. The annual survival rate of adults was on average more than twice that of juveniles and there was little regional variation within either age group. The onset of primary wing moult became progressively later northwards, but the duration of moult did not vary significantly with latitude. Juveniles started their first normally descendent wing moult sequence about one month after adults.
- Full Text:
- Date Issued: 2014
Adaptations in primary wing moult of southern African Viduidae and their hosts (Estrildidae)
- Bonnevie, Bo T, Oschadleus, Hans-Dieter
- Authors: Bonnevie, Bo T , Oschadleus, Hans-Dieter
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447691 , vital:74667 , https://doi.org/10.2989/00306525.2012.691910
- Description: Primary wing moult patterns in southern African brood-parasitic viduines were compared with those of their estrildid hosts. We searched for similarities in the timing and duration of moult within these closely related species potentially arising from their linked breeding biology and geographical distributions. Contrasting patterns were found between summer and winter rainfall regions, suggesting that climate dominates over phylogenetic effects on moult. Within the summer rainfall region different patterns of moult also emerged, and these generally supported the colonisation hypothesis of the host–brood parasite system. Moult estimates are provided for these taxa for which, until now, data have been mostly descriptive.
- Full Text:
- Date Issued: 2012
- Authors: Bonnevie, Bo T , Oschadleus, Hans-Dieter
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447691 , vital:74667 , https://doi.org/10.2989/00306525.2012.691910
- Description: Primary wing moult patterns in southern African brood-parasitic viduines were compared with those of their estrildid hosts. We searched for similarities in the timing and duration of moult within these closely related species potentially arising from their linked breeding biology and geographical distributions. Contrasting patterns were found between summer and winter rainfall regions, suggesting that climate dominates over phylogenetic effects on moult. Within the summer rainfall region different patterns of moult also emerged, and these generally supported the colonisation hypothesis of the host–brood parasite system. Moult estimates are provided for these taxa for which, until now, data have been mostly descriptive.
- Full Text:
- Date Issued: 2012
Wing moult and sexual dimorphism in the Lesser Honeyguide Indicator minor in the Eastern Cape, South Africa
- Craig, Adrian J F K, Bonnevie, Bo T, Hulley, Patrick E
- Authors: Craig, Adrian J F K , Bonnevie, Bo T , Hulley, Patrick E
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449593 , vital:74832 , https://www.tandfonline.com/doi/pdf/10.2989/00306525.2012.662918
- Description: Based on ringing data from the Western Cape, Underhill et al.(1995) demonstrated that there was a bimodal distribution of wing-length measurements in the Lesser Honeyguide Indicator minor, and they described the timing of wing-moult in this region. Hanmer (1997) reported similar results for Lesser Honeyguides from Mozambique and Malawi. This species remains poorly studied, and we have examined size dimorphism and wing moult for a sample of birds from the Eastern Cape region: 44 museum specimens from the Albany Museum (Grahamstown), East London Museum and the Ditsong Museum (formerly Transvaal Museum, Pretoria), together with ringing data for 94 birds. Wing-length of both museum specimens and ringed birds was measured in the standard manner (maximum chord); weight to the nearest 0.5 g was recorded with a Pesola spring balance. Each bird was checked for wing moult, which was recorded as 0 for an old feather and 5 for a fully grown new feather (de Beer et al. 2001). These moult scores were converted to percentage feather mass grown using a primary feather mass index, Passer9 (Bonnevie 2010a), for analysis using the model of Underhill and Zucchini (1988), as implemented in R (Erni et al. in press), with the data subsampled to prevent non-moulting birds from biasing the estimates (Bonnevie 2010b).
- Full Text:
- Date Issued: 2012
- Authors: Craig, Adrian J F K , Bonnevie, Bo T , Hulley, Patrick E
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449593 , vital:74832 , https://www.tandfonline.com/doi/pdf/10.2989/00306525.2012.662918
- Description: Based on ringing data from the Western Cape, Underhill et al.(1995) demonstrated that there was a bimodal distribution of wing-length measurements in the Lesser Honeyguide Indicator minor, and they described the timing of wing-moult in this region. Hanmer (1997) reported similar results for Lesser Honeyguides from Mozambique and Malawi. This species remains poorly studied, and we have examined size dimorphism and wing moult for a sample of birds from the Eastern Cape region: 44 museum specimens from the Albany Museum (Grahamstown), East London Museum and the Ditsong Museum (formerly Transvaal Museum, Pretoria), together with ringing data for 94 birds. Wing-length of both museum specimens and ringed birds was measured in the standard manner (maximum chord); weight to the nearest 0.5 g was recorded with a Pesola spring balance. Each bird was checked for wing moult, which was recorded as 0 for an old feather and 5 for a fully grown new feather (de Beer et al. 2001). These moult scores were converted to percentage feather mass grown using a primary feather mass index, Passer9 (Bonnevie 2010a), for analysis using the model of Underhill and Zucchini (1988), as implemented in R (Erni et al. in press), with the data subsampled to prevent non-moulting birds from biasing the estimates (Bonnevie 2010b).
- Full Text:
- Date Issued: 2012
Geographic variation in the trophic ecology of an avian rocky shore predator, the African black oystercatcher, along the southern African coastline
- Kohler, Sophie A, Connan, Maëlle, Hill, Jaclyn M, Mablouké, Cécile, Bonnevie, Bo T, Ludynia, Katrin, Kemper, Jessica, Huisamen, Johan, Underhill, Leslie G, Cherel, Yves, McQuaid, Christopher D, Jaquemet, Sébastien
- Authors: Kohler, Sophie A , Connan, Maëlle , Hill, Jaclyn M , Mablouké, Cécile , Bonnevie, Bo T , Ludynia, Katrin , Kemper, Jessica , Huisamen, Johan , Underhill, Leslie G , Cherel, Yves , McQuaid, Christopher D , Jaquemet, Sébastien
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444576 , vital:74252 , https://doi.org/10.3354/meps09215
- Description: The reflection of baseline isotopic signals along marine food chains up to higher trophic levels has been widely used in the study of oceanic top predators but rarely for intertidal predators. We investigated variation in the δ 13 C and δ 15 N ratios of a sedentary, rocky shore predator, the African black oystercatcher Haematopus moquini, over~ 2000 km of the southern African coastline, which is characterized by strong biogeographic patterns in primary productivity and intertidal communities. Blood and feathers from breeding adults and chicks and muscle tissues from primary prey items (mussels and limpets) were sampled between southern Namibia and the southeast coast of South Africa. 15 N enrichment was observed between the southeast and west coasts in oystercatcher tissues and their prey, mirroring an isotope shift between the oligotrophic Agulhas Current on the east coast and the eutrophic Benguela upwelling system on the west coast.
- Full Text:
- Date Issued: 2011
- Authors: Kohler, Sophie A , Connan, Maëlle , Hill, Jaclyn M , Mablouké, Cécile , Bonnevie, Bo T , Ludynia, Katrin , Kemper, Jessica , Huisamen, Johan , Underhill, Leslie G , Cherel, Yves , McQuaid, Christopher D , Jaquemet, Sébastien
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444576 , vital:74252 , https://doi.org/10.3354/meps09215
- Description: The reflection of baseline isotopic signals along marine food chains up to higher trophic levels has been widely used in the study of oceanic top predators but rarely for intertidal predators. We investigated variation in the δ 13 C and δ 15 N ratios of a sedentary, rocky shore predator, the African black oystercatcher Haematopus moquini, over~ 2000 km of the southern African coastline, which is characterized by strong biogeographic patterns in primary productivity and intertidal communities. Blood and feathers from breeding adults and chicks and muscle tissues from primary prey items (mussels and limpets) were sampled between southern Namibia and the southeast coast of South Africa. 15 N enrichment was observed between the southeast and west coasts in oystercatcher tissues and their prey, mirroring an isotope shift between the oligotrophic Agulhas Current on the east coast and the eutrophic Benguela upwelling system on the west coast.
- Full Text:
- Date Issued: 2011
Some considerations when comparing SABAP 1 with SABAP 2 data
- Authors: Bonnevie, Bo T
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448327 , vital:74722 , https://doi.org/10.2989/00306525.2011.603486
- Description: Generally, one should be cautious when comparing data that have not been collected in the same manner. The data collection methods of the South African Bird Atlas Projects, SABAP 1 (Harrison et al. 1997) and SABAP 2 (in progress at the time of writing), differ both spatially and temporally. On the spatial scale SABAP 1 used predominantly quarter degree cells (15′ by 15′), whereas SABAP 2 uses pentads (5′ by 5′; one quarter-degree cell containing nine pentads). On a temporal scale SABAP 1 used one calendar month, whereas SABAP 2 is using one pentade (five days). Where possible, however, SABAP 1 used pentades post hoc for seasonality modelling (Harrison et al. 1997, pp lviii–lix). Because of, but possibly not limited to, this, caution will need to be exercised when comparing data between the two projects. It is naturally desirable to compare the data between these projects, particularly to seek long-term trends in population densities and in the potential changes in the distribution of species.
- Full Text:
- Date Issued: 2011
- Authors: Bonnevie, Bo T
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448327 , vital:74722 , https://doi.org/10.2989/00306525.2011.603486
- Description: Generally, one should be cautious when comparing data that have not been collected in the same manner. The data collection methods of the South African Bird Atlas Projects, SABAP 1 (Harrison et al. 1997) and SABAP 2 (in progress at the time of writing), differ both spatially and temporally. On the spatial scale SABAP 1 used predominantly quarter degree cells (15′ by 15′), whereas SABAP 2 uses pentads (5′ by 5′; one quarter-degree cell containing nine pentads). On a temporal scale SABAP 1 used one calendar month, whereas SABAP 2 is using one pentade (five days). Where possible, however, SABAP 1 used pentades post hoc for seasonality modelling (Harrison et al. 1997, pp lviii–lix). Because of, but possibly not limited to, this, caution will need to be exercised when comparing data between the two projects. It is naturally desirable to compare the data between these projects, particularly to seek long-term trends in population densities and in the potential changes in the distribution of species.
- Full Text:
- Date Issued: 2011
Balancing moult data by subsampling non-moulting birds prior to regression analysis
- Authors: Bonnevie, Bo T
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448057 , vital:74694 , https://doi.org/10.2989/00306525.2010.517941
- Description: During the analysis of moult records from the SAFRING database it was found that for some datasets the records were not evenly distributed temporally and the proportion of moulting to non-moulting birds was not what would be expected from random sampling. In an attempt to balance these data, the records of non-moulting birds were subsampled with different sample sizes prior to moult regression analysis, and the resulting moult estimates were then compared. The results suggest that subsampling non-moulting birds such that they occur in the expected proportion to actively moulting birds, based on the duration of moult, provides the best estimates of moult.
- Full Text:
- Date Issued: 2010
- Authors: Bonnevie, Bo T
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448057 , vital:74694 , https://doi.org/10.2989/00306525.2010.517941
- Description: During the analysis of moult records from the SAFRING database it was found that for some datasets the records were not evenly distributed temporally and the proportion of moulting to non-moulting birds was not what would be expected from random sampling. In an attempt to balance these data, the records of non-moulting birds were subsampled with different sample sizes prior to moult regression analysis, and the resulting moult estimates were then compared. The results suggest that subsampling non-moulting birds such that they occur in the expected proportion to actively moulting birds, based on the duration of moult, provides the best estimates of moult.
- Full Text:
- Date Issued: 2010
Regional patterns in moult and sexual dimorphism of adult Southern Red Bishops Euplectes orix in southern Africa
- Craig, Adrian J F K, Bonnevie, Bo T, Oschadleus, Hans-Dieter
- Authors: Craig, Adrian J F K , Bonnevie, Bo T , Oschadleus, Hans-Dieter
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449503 , vital:74826 , https://doi.org/10.2989/00306525.2010.488357
- Description: Using the SAFRING database and the Underhill-Zucchini model of primary moult, we analysed the timing of wing moult in Southern Red Bishops Euplectes orix in relation to sex and geographical region. Birds from the winter rainfall region in the south-western sector of the Western Cape start the annual moult more than two months before any other population, but there were no significant differences in starting date within the summer rainfall region. There were striking differences in the estimates of moult duration (62–114 d), which did not follow a consistent pattern in relation to sex or geography; annual variation within a region may be an additional factor. Throughout southern Africa, both sexes showed a trend for longer-winged birds to take more time to complete their moult. We suggest that sex, geographical area and possible annual environmental variations may all influence the timing of moult in local populations. In this sexually dimorphic species, males are consistently longer-winged and heavier than females.
- Full Text:
- Date Issued: 2010
- Authors: Craig, Adrian J F K , Bonnevie, Bo T , Oschadleus, Hans-Dieter
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449503 , vital:74826 , https://doi.org/10.2989/00306525.2010.488357
- Description: Using the SAFRING database and the Underhill-Zucchini model of primary moult, we analysed the timing of wing moult in Southern Red Bishops Euplectes orix in relation to sex and geographical region. Birds from the winter rainfall region in the south-western sector of the Western Cape start the annual moult more than two months before any other population, but there were no significant differences in starting date within the summer rainfall region. There were striking differences in the estimates of moult duration (62–114 d), which did not follow a consistent pattern in relation to sex or geography; annual variation within a region may be an additional factor. Throughout southern Africa, both sexes showed a trend for longer-winged birds to take more time to complete their moult. We suggest that sex, geographical area and possible annual environmental variations may all influence the timing of moult in local populations. In this sexually dimorphic species, males are consistently longer-winged and heavier than females.
- Full Text:
- Date Issued: 2010
Relative feather mass indices: are feather masses needed to estimate the percentage of new feather mass grown for moult regression models?
- Authors: Bonnevie, Bo T
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448313 , vital:74721 , https://doi.org/10.2989/00306525.2010.455820
- Description: During the moult of primary wing feathers in birds it is likely that new feather material is being produced at an approximately constant rate if the energetic requirements of the birds are met. In moult regression analyses it is, therefore, desirable to transform moult measurements into a variable based on the amount of new feather material produced because of its linear properties. This can be achieved if the mass of each primary feather is known, and used as a weighting factor in a moult index. These primary feather masses would have to be known for every species being analysed. As an alternative, it is here tested if feather mass indices may be sufficient replacements for species-specific feather masses. Thirty-five species of birds with known primary feather masses were divided into four wing-shape groups, and a feather mass index was built for each group. Within each group, comparisons were made between estimates of moult parameters using the moult index with those using the known primary feather masses. Within groups there were no significant differences between any of the moult estimates.
- Full Text:
- Date Issued: 2010
- Authors: Bonnevie, Bo T
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448313 , vital:74721 , https://doi.org/10.2989/00306525.2010.455820
- Description: During the moult of primary wing feathers in birds it is likely that new feather material is being produced at an approximately constant rate if the energetic requirements of the birds are met. In moult regression analyses it is, therefore, desirable to transform moult measurements into a variable based on the amount of new feather material produced because of its linear properties. This can be achieved if the mass of each primary feather is known, and used as a weighting factor in a moult index. These primary feather masses would have to be known for every species being analysed. As an alternative, it is here tested if feather mass indices may be sufficient replacements for species-specific feather masses. Thirty-five species of birds with known primary feather masses were divided into four wing-shape groups, and a feather mass index was built for each group. Within each group, comparisons were made between estimates of moult parameters using the moult index with those using the known primary feather masses. Within groups there were no significant differences between any of the moult estimates.
- Full Text:
- Date Issued: 2010
Timing of primary wing moult in sexually dimorphic passerines from the Western Cape, South Africa
- Bonnevie, Bo T, Oschadleus, Hans-Dieter
- Authors: Bonnevie, Bo T , Oschadleus, Hans-Dieter
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448355 , vital:74724 , https://doi.org/10.2989/00306525.2010.455821
- Description: SAFRING ringing data was used to investigate the differences in the timing and duration of primary wing moult between males and females of sexually dimorphic passerines from the Western Cape, South Africa. In the sunbirds, weavers and canaries that were considered, the males generally started moult before the females, whereas this was not so for other species. In the species where males started moult before the females, the standard deviation of the start of moult was generally smaller in the males and the males generally took longer to moult. These differences in the patterns of moult are discussed in the context of differences in parental care between males and females of each species and within their taxonomic groups.
- Full Text:
- Date Issued: 2010
- Authors: Bonnevie, Bo T , Oschadleus, Hans-Dieter
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448355 , vital:74724 , https://doi.org/10.2989/00306525.2010.455821
- Description: SAFRING ringing data was used to investigate the differences in the timing and duration of primary wing moult between males and females of sexually dimorphic passerines from the Western Cape, South Africa. In the sunbirds, weavers and canaries that were considered, the males generally started moult before the females, whereas this was not so for other species. In the species where males started moult before the females, the standard deviation of the start of moult was generally smaller in the males and the males generally took longer to moult. These differences in the patterns of moult are discussed in the context of differences in parental care between males and females of each species and within their taxonomic groups.
- Full Text:
- Date Issued: 2010
Trophic ecology of grey-headed albatrosses from Marion Island, Southern Ocean: insights from stomach contents and diet tracers
- Richoux, Nicole B, Jaquemet, Se´bastien, Bonnevie, Bo T, Cherel, Yves, McQuaid, Christopher D
- Authors: Richoux, Nicole B , Jaquemet, Se´bastien , Bonnevie, Bo T , Cherel, Yves , McQuaid, Christopher D
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/458019 , vital:75710 , xlink:href="https://doi.org/10.1007/s00227-010-1448-y"
- Description: During chick-rearing, albatrosses can alternate between long foraging trips that provide the main source of food for the adults and short foraging trips that they use to feed their young. This flexibility in foraging behaviour can lead to differences in diet composition between adults and chicks and implies that they may be vulnerable in different ways to food shortages. The trophic ecology of the Grey-headed albatross Thalassarche chrysostoma was investigated at the sub-Antarctic Prince Edward Islands during the chick-rearing period in April 2006 using a combination of approaches. Diets of adults and chicks were assessed using stable isotope ratios and fatty acid (FA) profiles of blood and/or stomach oils, in addition to stomach contents analysis. Fish from the family Macrouridae and cephalopods (particularly the onychoteuthid Kondakovia longimana) were the primary prey, whereas crustaceans (krill Euphausia superba) represented a smaller proportion of the stomach contents. Stomach oil FA profiles contained more monounsaturated FA than the profiles of plasma, which were richer in saturated FA and arachidonic acid (20:4n-6). There was also a distinct separation of adults from chicks, with higher levels of monounsaturates in chick plasma, and higher saturated FA levels (particularly 16:0) in the adult plasma. Stable carbon isotope ratios of whole blood were similar in adults and chicks, whereas stable nitrogen isotope ratios showed significant enrichment by >1‰ in chicks. The combined FA, stable isotopes and stomach contents analyses suggest clear differences in diet quality between adults and chicks, with chicks feeding at a higher trophic position through feeding more on highly nutritious fish and adults keeping much of the less nutritious zooplankton for themselves.
- Full Text:
- Date Issued: 2010
- Authors: Richoux, Nicole B , Jaquemet, Se´bastien , Bonnevie, Bo T , Cherel, Yves , McQuaid, Christopher D
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/458019 , vital:75710 , xlink:href="https://doi.org/10.1007/s00227-010-1448-y"
- Description: During chick-rearing, albatrosses can alternate between long foraging trips that provide the main source of food for the adults and short foraging trips that they use to feed their young. This flexibility in foraging behaviour can lead to differences in diet composition between adults and chicks and implies that they may be vulnerable in different ways to food shortages. The trophic ecology of the Grey-headed albatross Thalassarche chrysostoma was investigated at the sub-Antarctic Prince Edward Islands during the chick-rearing period in April 2006 using a combination of approaches. Diets of adults and chicks were assessed using stable isotope ratios and fatty acid (FA) profiles of blood and/or stomach oils, in addition to stomach contents analysis. Fish from the family Macrouridae and cephalopods (particularly the onychoteuthid Kondakovia longimana) were the primary prey, whereas crustaceans (krill Euphausia superba) represented a smaller proportion of the stomach contents. Stomach oil FA profiles contained more monounsaturated FA than the profiles of plasma, which were richer in saturated FA and arachidonic acid (20:4n-6). There was also a distinct separation of adults from chicks, with higher levels of monounsaturates in chick plasma, and higher saturated FA levels (particularly 16:0) in the adult plasma. Stable carbon isotope ratios of whole blood were similar in adults and chicks, whereas stable nitrogen isotope ratios showed significant enrichment by >1‰ in chicks. The combined FA, stable isotopes and stomach contents analyses suggest clear differences in diet quality between adults and chicks, with chicks feeding at a higher trophic position through feeding more on highly nutritious fish and adults keeping much of the less nutritious zooplankton for themselves.
- Full Text:
- Date Issued: 2010
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
Can eyeflecks be used to sex African Black Oystercatchers Haematopus moquini in the field?
- Kohler, Sophie, Bonnevie, Bo T, Dano, Stéphanie
- 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
- 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
Nesting success and survival rates of suburban Olive Thrushes (Turdus olivaceus olivaceus).
- Authors: Bonnevie, Bo T
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448299 , vital:74720 , https://doi.org/10.2989/OSTRICH.2007.78.2.19.99
- Description: Adult survival rates of suburban Olive Thrushes (Turdus olivaceus) were estimated from the proportion of adults and juveniles in mist-net samples from the Eastern Cape and Western Cape provinces of South Africa. These survival rates were compared to an estimate from recovery data. Reproductive rate, clutch size, nesting success and survival rate of dependent fledglings were estimated from breeding records in the Eastern Cape. These data were used to estimate survival rate of independent fledglings. The estimated adult survival rate in this region was high and the clutch size was small, compared to those of the Blackbird (Turdus merula) in Europe. Dispersal patterns from recapture and recovery data, and the relatively low survival rates of juvenile birds, suggest that fledglings are most vulnerable when they reach independence and leave their natal territories.
- Full Text:
- Date Issued: 2007
- Authors: Bonnevie, Bo T
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448299 , vital:74720 , https://doi.org/10.2989/OSTRICH.2007.78.2.19.99
- Description: Adult survival rates of suburban Olive Thrushes (Turdus olivaceus) were estimated from the proportion of adults and juveniles in mist-net samples from the Eastern Cape and Western Cape provinces of South Africa. These survival rates were compared to an estimate from recovery data. Reproductive rate, clutch size, nesting success and survival rate of dependent fledglings were estimated from breeding records in the Eastern Cape. These data were used to estimate survival rate of independent fledglings. The estimated adult survival rate in this region was high and the clutch size was small, compared to those of the Blackbird (Turdus merula) in Europe. Dispersal patterns from recapture and recovery data, and the relatively low survival rates of juvenile birds, suggest that fledglings are most vulnerable when they reach independence and leave their natal territories.
- Full Text:
- Date Issued: 2007
Additional morphological characteristics of Olive Thrushes and Karoo Thrushes
- Bonnevie, Bo T, Craig, Adrian J F K, Hulley, Patrick E
- Authors: Bonnevie, Bo T , Craig, Adrian J F K , Hulley, Patrick E
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447712 , vital:74669 , https://www.tandfonline.com/doi/pdf/10.2989/00306520409485415
- Description: A southern race of the Olive Thrush, Turdus olivaceus smithi Bonaparte, has recently been proposed as a full species, the Karoo Thrush Turdus smithi (Bowie et al. 2003). Some of the published information on the Olive Thrush Turdus olivaceus olivaceus thus pertains to the Karoo Thrush (eg Kopij 2000), whereas other information deals specifically with the Olive Thrush (eg Winterbottom 1966, Bonnevie et al. 2003). We have ringed, recaptured and recovered both Olive and Karoo Thrushes in the Eastern Cape since 1986, and the two taxa are markedly different in this region. We describe some differences in appearance of the two populations from these data, and compare mass and wing length of living birds, as well as culmen and tarsus lengths of museum specimens from the East London Museum, South Africa. The collection sites of the museum specimens were mapped using ArcView 3.1 (ESRI 1996) together with the ringing sites (Figure 1). Areas of potential sympatry are Oudtshoorn (33 25’S, 22 11’E) and Patensie (33 45’S, 24 48’E).
- Full Text:
- Date Issued: 2004
- Authors: Bonnevie, Bo T , Craig, Adrian J F K , Hulley, Patrick E
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447712 , vital:74669 , https://www.tandfonline.com/doi/pdf/10.2989/00306520409485415
- Description: A southern race of the Olive Thrush, Turdus olivaceus smithi Bonaparte, has recently been proposed as a full species, the Karoo Thrush Turdus smithi (Bowie et al. 2003). Some of the published information on the Olive Thrush Turdus olivaceus olivaceus thus pertains to the Karoo Thrush (eg Kopij 2000), whereas other information deals specifically with the Olive Thrush (eg Winterbottom 1966, Bonnevie et al. 2003). We have ringed, recaptured and recovered both Olive and Karoo Thrushes in the Eastern Cape since 1986, and the two taxa are markedly different in this region. We describe some differences in appearance of the two populations from these data, and compare mass and wing length of living birds, as well as culmen and tarsus lengths of museum specimens from the East London Museum, South Africa. The collection sites of the museum specimens were mapped using ArcView 3.1 (ESRI 1996) together with the ringing sites (Figure 1). Areas of potential sympatry are Oudtshoorn (33 25’S, 22 11’E) and Patensie (33 45’S, 24 48’E).
- Full Text:
- Date Issued: 2004
Song and breeding observations of suburban Olive Thrushes (Turdus olivaceus olivaceus) in Grahamstown, South Africa
- Authors: Bonnevie, Bo T
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448342 , vital:74723 , https://doi.org/10.2989/00306520409485422
- Description: Olive Thrushes Turdus olivaceus olivaceus in Grahamstown, South Africa, were present in their territories throughout the year. Mist-net captures showed no seasonal fluctuation in the population density of adults. The breeding season had a main peak from August to November and a minor peak in April. Song output was greatest at the beginning of the breeding periods, when territorial boundaries were most keenly contested. There was a positive correlation between seasonal variation in breeding intensity and song output. The adult survival rate was estimated at 80%, and 56% of the fledglings were alive in their natal territories at the age of independence. In this study area, only females built nests and brooded nestlings. Only males sang. Both males and females defended their territories.
- Full Text:
- Date Issued: 2004
- Authors: Bonnevie, Bo T
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448342 , vital:74723 , https://doi.org/10.2989/00306520409485422
- Description: Olive Thrushes Turdus olivaceus olivaceus in Grahamstown, South Africa, were present in their territories throughout the year. Mist-net captures showed no seasonal fluctuation in the population density of adults. The breeding season had a main peak from August to November and a minor peak in April. Song output was greatest at the beginning of the breeding periods, when territorial boundaries were most keenly contested. There was a positive correlation between seasonal variation in breeding intensity and song output. The adult survival rate was estimated at 80%, and 56% of the fledglings were alive in their natal territories at the age of independence. In this study area, only females built nests and brooded nestlings. Only males sang. Both males and females defended their territories.
- Full Text:
- Date Issued: 2004
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