Behavioural ecology of the Redbilled Woodhoopoe Phoeniculus purpureus in South Africa

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dc.contributor.advisorHockey, Phil A Ren_ZA
dc.contributor.authorDu Plessis, Morne Andreen_ZA
dc.date.accessioned2014-08-13T14:17:27Z
dc.date.available2014-08-13T14:17:27Z
dc.date.issued1989en_ZA
dc.descriptionIncludes bibliographies.en_ZA
dc.description.abstractA study was made of two Redbilled (Green) Woodhoopoe Phoeniculus purpureus populations spanning an eight year period (1981-1988) and 258 'flock-years', in the eastern Cape Province of South Mrica. The main objectives of the study were to investigate (1) why woodhoopoes live in groups; (2) why nonbreeders do not breed; and, (3) why nonbreeders provision young that are not their own? Ecological and demographic data were gathered in addition to detailed behavioural observations of 54 woodhoopoe flocks. The following experimental manipulations were performed: (1) breeders were removed from flocks to (a) monitor dispersal patterns and restructuring of flocks; and, (b) observe behavioural reactions by remaining birds; (2) cavity availability was (a) decreased, to enable quantification of availability; and, (b) increased, by addition of nest/roost boxes to an area which supported no permanent woodhoopoe territories; and, (3) stimuli, associated with the food provisioning response of adult birds, were manipulated to investigate the evolutionary basis of allofeeding behaviour Variability in social and reproductive behaviour reflects environmental selection pressures, in the form of roost-cavity availability, with a reduction in cavity availability leading to increased group size. The group-territorial social system and high level of inbreeding of Redbilled Woodhoopoes have evolved primarily in response to environmental constraints on dispersal, rather than by particular benefits that arise from group living. Therefore, the habitat-saturation hypothesis best explains group living of woodhoopoes. Behavioural dominance hierarchies ensure that dominance relationships are well-defined among potential competitors (for breeding status), and thereby minimize disruption to flock cohesion upon the death (or removal) of a breeder. If competition for a breeding vacancy arose at the time of the breeder's death, the resultant delay in occupancy of the breeding vacancy would increase the likelihood of competition from unrelated birds. The establishment of such hierarchies is therefore adaptive in the context of the direct component of kin selection. The presence of nonbreeding helpers do not increase fledgling success, breeding frequency, survivorship (of any age, sex or social class), or number of breeder-offspring produced. Because no unambiguous indirect fitness benefits could be shown to result from helping behaviour (specifically allofeeding), I propose that the unselected (misdirected parental care) hypothesis is a viable alternative to the 'functional hypotheses.' This hypothesis is supported by observations/manipulations of misdirected food provisioning by both breeders and helpers.en_ZA
dc.identifier.apacitationDu Plessis, M. A. (1989). <i>Behavioural ecology of the Redbilled Woodhoopoe Phoeniculus purpureus in South Africa</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/6252en_ZA
dc.identifier.chicagocitationDu Plessis, Morne Andre. <i>"Behavioural ecology of the Redbilled Woodhoopoe Phoeniculus purpureus in South Africa."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 1989. http://hdl.handle.net/11427/6252en_ZA
dc.identifier.citationDu Plessis, M. 1989. Behavioural ecology of the Redbilled Woodhoopoe Phoeniculus purpureus in South Africa. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Du Plessis, Morne Andre AB - A study was made of two Redbilled (Green) Woodhoopoe Phoeniculus purpureus populations spanning an eight year period (1981-1988) and 258 'flock-years', in the eastern Cape Province of South Mrica. The main objectives of the study were to investigate (1) why woodhoopoes live in groups; (2) why nonbreeders do not breed; and, (3) why nonbreeders provision young that are not their own? Ecological and demographic data were gathered in addition to detailed behavioural observations of 54 woodhoopoe flocks. The following experimental manipulations were performed: (1) breeders were removed from flocks to (a) monitor dispersal patterns and restructuring of flocks; and, (b) observe behavioural reactions by remaining birds; (2) cavity availability was (a) decreased, to enable quantification of availability; and, (b) increased, by addition of nest/roost boxes to an area which supported no permanent woodhoopoe territories; and, (3) stimuli, associated with the food provisioning response of adult birds, were manipulated to investigate the evolutionary basis of allofeeding behaviour Variability in social and reproductive behaviour reflects environmental selection pressures, in the form of roost-cavity availability, with a reduction in cavity availability leading to increased group size. The group-territorial social system and high level of inbreeding of Redbilled Woodhoopoes have evolved primarily in response to environmental constraints on dispersal, rather than by particular benefits that arise from group living. Therefore, the habitat-saturation hypothesis best explains group living of woodhoopoes. Behavioural dominance hierarchies ensure that dominance relationships are well-defined among potential competitors (for breeding status), and thereby minimize disruption to flock cohesion upon the death (or removal) of a breeder. If competition for a breeding vacancy arose at the time of the breeder's death, the resultant delay in occupancy of the breeding vacancy would increase the likelihood of competition from unrelated birds. The establishment of such hierarchies is therefore adaptive in the context of the direct component of kin selection. The presence of nonbreeding helpers do not increase fledgling success, breeding frequency, survivorship (of any age, sex or social class), or number of breeder-offspring produced. Because no unambiguous indirect fitness benefits could be shown to result from helping behaviour (specifically allofeeding), I propose that the unselected (misdirected parental care) hypothesis is a viable alternative to the 'functional hypotheses.' This hypothesis is supported by observations/manipulations of misdirected food provisioning by both breeders and helpers. DA - 1989 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1989 T1 - Behavioural ecology of the Redbilled Woodhoopoe Phoeniculus purpureus in South Africa TI - Behavioural ecology of the Redbilled Woodhoopoe Phoeniculus purpureus in South Africa UR - http://hdl.handle.net/11427/6252 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/6252
dc.identifier.vancouvercitationDu Plessis MA. Behavioural ecology of the Redbilled Woodhoopoe Phoeniculus purpureus in South Africa. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 1989 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/6252en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Biological Sciencesen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherZoologyen_ZA
dc.titleBehavioural ecology of the Redbilled Woodhoopoe Phoeniculus purpureus in South Africaen_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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