Sunbird Movements: a Review, with Posslble Models
- Craig, Adrian J F K, Hulley, Patrick E
- Authors: Craig, Adrian J F K , Hulley, Patrick E
- Date: 1994
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447856 , vital:74679 , https://doi.org/10.1080/00306525.1994.9639672
- Description: Based on current fieldwork, we propose four possible models to explain the winter influx of sunbirds which we have observed: the birds may be (1) “winter residents”, which move annually to a wintering area and remain there; (2) “shoppers”, which periodically investigate feeding areas within their home range and feed opportunistically where nectar is most abundant; (3) “tourists”, which successively visit a series of sites on a regular itinerary; (4) “nomads”, which move unpredictably to new areas whenever food supplies decline. and have no home base. Current data on sunbird movements are reviewed, and in a few cases the winter resident model is unlikely, but generally it is not yet possible to eliminate any of the hypotheses. Moult cycles based on both field and museum studies may provide additional information, as movements are unlikely while active wing-moult is in progress; some species show interrupted wing-moult, which may be associated with long-distance flights.
- Full Text:
- Date Issued: 1994
- Authors: Craig, Adrian J F K , Hulley, Patrick E
- Date: 1994
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447856 , vital:74679 , https://doi.org/10.1080/00306525.1994.9639672
- Description: Based on current fieldwork, we propose four possible models to explain the winter influx of sunbirds which we have observed: the birds may be (1) “winter residents”, which move annually to a wintering area and remain there; (2) “shoppers”, which periodically investigate feeding areas within their home range and feed opportunistically where nectar is most abundant; (3) “tourists”, which successively visit a series of sites on a regular itinerary; (4) “nomads”, which move unpredictably to new areas whenever food supplies decline. and have no home base. Current data on sunbird movements are reviewed, and in a few cases the winter resident model is unlikely, but generally it is not yet possible to eliminate any of the hypotheses. Moult cycles based on both field and museum studies may provide additional information, as movements are unlikely while active wing-moult is in progress; some species show interrupted wing-moult, which may be associated with long-distance flights.
- Full Text:
- Date Issued: 1994
Insect herbivores on the exotic weeds Solanum elaeagnifolium Cavanilles and S. sisymbriifolium Lamarck (Solanaceae) in South Africa
- Hill, Martin P, Hulley, Patrick E, Olckers, T
- Authors: Hill, Martin P , Hulley, Patrick E , Olckers, T
- Date: 1993
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451454 , vital:75050 , https://hdl.handle.net/10520/AJA10213589_58
- Description: In South Africa, the weeds Solanum elaeagnifolium Cavanilles and S. sisymbriifolium Lamarck (Solanaceae) sustain little observable damage from herbivorous insects. Relatively few insect species occur on these plants and at low individual densities. Since native insects are not important in the natural control of S. elaeagnifolium and S. sisymbriifolium, additional agents should be imported for the biological control of these weeds. The absence of important local herbivores means that the possibility of interaction between these and potential biological control agents need not be a consideration in choosing the agents. The nature and numbers of the insect herbivores of S. elaeagnifolium and S. sisymbriifolium are compared with those on another solanaceous weed, S. mauritianum Scopoli, and on native Solanum species. These insect species are discussed relative to plant defence mechanisms.
- Full Text:
- Date Issued: 1993
- Authors: Hill, Martin P , Hulley, Patrick E , Olckers, T
- Date: 1993
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451454 , vital:75050 , https://hdl.handle.net/10520/AJA10213589_58
- Description: In South Africa, the weeds Solanum elaeagnifolium Cavanilles and S. sisymbriifolium Lamarck (Solanaceae) sustain little observable damage from herbivorous insects. Relatively few insect species occur on these plants and at low individual densities. Since native insects are not important in the natural control of S. elaeagnifolium and S. sisymbriifolium, additional agents should be imported for the biological control of these weeds. The absence of important local herbivores means that the possibility of interaction between these and potential biological control agents need not be a consideration in choosing the agents. The nature and numbers of the insect herbivores of S. elaeagnifolium and S. sisymbriifolium are compared with those on another solanaceous weed, S. mauritianum Scopoli, and on native Solanum species. These insect species are discussed relative to plant defence mechanisms.
- Full Text:
- Date Issued: 1993
The Behaviour Of Palewinged Starlings And A Comparison With Other Onychognathvs Species
- Craig, Adrian J F K, Hulley, Patrick E, Walter, Grenville H
- Authors: Craig, Adrian J F K , Hulley, Patrick E , Walter, Grenville H
- Date: 1991
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447868 , vital:74680 , https://doi.org/10.1080/00306525.1991.9639648
- Description: Pairs of Palewinged Starlings associate throughout the year and roost at the nest sites. Flock sizes are generally small, even during the non-breeding season. Allofeeding and allopreening have not been recorded. Wing displays emphasize the white region of the primaries. The territory appears to be restricted to the nest site. Interspecific aggression occurred between Redwinged and Palewinged Starlings, and was also directed at other Ed species frequenting the cliff. A form of ceremonial gathering occurs re in Palewinged Starlings. A review of the literature suggests that on behavioural grounds the Palewinged Starling shows no close affinity to the Redwinged Starfng or to any other member of the genus.
- Full Text:
- Date Issued: 1991
- Authors: Craig, Adrian J F K , Hulley, Patrick E , Walter, Grenville H
- Date: 1991
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447868 , vital:74680 , https://doi.org/10.1080/00306525.1991.9639648
- Description: Pairs of Palewinged Starlings associate throughout the year and roost at the nest sites. Flock sizes are generally small, even during the non-breeding season. Allofeeding and allopreening have not been recorded. Wing displays emphasize the white region of the primaries. The territory appears to be restricted to the nest site. Interspecific aggression occurred between Redwinged and Palewinged Starlings, and was also directed at other Ed species frequenting the cliff. A form of ceremonial gathering occurs re in Palewinged Starlings. A review of the literature suggests that on behavioural grounds the Palewinged Starling shows no close affinity to the Redwinged Starfng or to any other member of the genus.
- Full Text:
- Date Issued: 1991
Nesting of sympatric redwinged and pale winged starlings
- Craig, Adrian J F K, Hulley, Patrick E, Walter, Grenville H
- Authors: Craig, Adrian J F K , Hulley, Patrick E , Walter, Grenville H
- Date: 1989
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447827 , vital:74677 , https://doi.org/10.1080/00306525.1989.9634513
- Description: Observations were made over four breeding seasons at Cradock, South Africa, where Redwinged Starlings Onychognathus morio and Palewinged Starlings O. nabouroup nest on the same cliffs. Nests were not accessible, and the stage of breeding was determined by the behaviour of the birds. Both species reuse the same nest sites, and only the females incubate, but both sexes feed the young. The timing of breedingMaybe more variable in the Palewinged Starling. A review of the available data on nest site selection and nest construction shows apparent species-specific differences: Redwinged Starlings usually nest on ledges, often on buildings, and use mud in the nest base; Palewinged Starlings favour vertical crevices, and do not use mud.
- Full Text:
- Date Issued: 1989
- Authors: Craig, Adrian J F K , Hulley, Patrick E , Walter, Grenville H
- Date: 1989
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447827 , vital:74677 , https://doi.org/10.1080/00306525.1989.9634513
- Description: Observations were made over four breeding seasons at Cradock, South Africa, where Redwinged Starlings Onychognathus morio and Palewinged Starlings O. nabouroup nest on the same cliffs. Nests were not accessible, and the stage of breeding was determined by the behaviour of the birds. Both species reuse the same nest sites, and only the females incubate, but both sexes feed the young. The timing of breedingMaybe more variable in the Palewinged Starling. A review of the available data on nest site selection and nest construction shows apparent species-specific differences: Redwinged Starlings usually nest on ledges, often on buildings, and use mud in the nest base; Palewinged Starlings favour vertical crevices, and do not use mud.
- Full Text:
- Date Issued: 1989