How does temperature affect Fork-tailed Drongo, Dicrurus adsimilis, foraging effort, nestling provisioning and growth rates?

Simple item page
dc.contributor.advisorCunningham, Susan Jen_ZA
dc.contributor.advisorFlower, Thomasen_ZA
dc.contributor.authorOlinger, Ryanen_ZA
dc.date.accessioned2017-09-06T07:00:23Z
dc.date.available2017-09-06T07:00:23Z
dc.date.issued2017en_ZA
dc.description.abstractGlobal average temperatures are predicted to increase by as much as 5ᵒC by 2100. Therefore, it is imperative to identify how species are affected by temperature increase to ensure that proper conservation and management of wildlife can be implemented. Species which already live in warmer climates, such as deserts, may provide the first clues to the impacts of increasing temperatures. Birds represent an ideal indicator because research has shown that rising temperatures affect their behaviour, including foraging and provisioning of young, thereby reducing reproductive success. However, it remains unclear whether this results from physiological constraints on behaviour, from declining food availability and or access to prey items at high temperatures. In this study, I aimed to identify how temperature affects the foraging and provisioning behaviour of wild Fork-tailed Drongos, Dicrurus adsimilis, when supplemental food is provided. Additionally, I aimed to identify how nestling growth rates change with temperature. The results of two supplemental feeding experiments indicated that as temperatures increased, adults significantly reduced their willingness to forage, reduced provisioning to offspring and exhibited increased rates of heat dissipation behaviour. Furthermore, when provisioning nestlings, adult drongos consumed a larger proportion of supplementary food at higher air temperatures, and provisioned less. This suggests that they suffer greater provisioning costs at such times. Surprisingly, despite finding several negative effects of temperatures on adults' willingness to forage and provisioning, there was only a weak and non-significant effect of temperature on nestling growth rates. This suggests that adults may be able to compensate for reduced foraging at high temperatures. My study shows that the increased thermoregulatory costs of activity at high temperatures can constrain foraging and provisioning, even when food remains abundant. However, whether this impacts the fitness of current offspring or parents future reproductive success remains unclear.en_ZA
dc.identifier.apacitationOlinger, R. (2017). <i>How does temperature affect Fork-tailed Drongo, Dicrurus adsimilis, foraging effort, nestling provisioning and growth rates?</i>. (Thesis). University of Cape Town ,Faculty of Science ,Percy FitzPatrick Institute of African Ornithology. Retrieved from http://hdl.handle.net/11427/25053en_ZA
dc.identifier.chicagocitationOlinger, Ryan. <i>"How does temperature affect Fork-tailed Drongo, Dicrurus adsimilis, foraging effort, nestling provisioning and growth rates?."</i> Thesis., University of Cape Town ,Faculty of Science ,Percy FitzPatrick Institute of African Ornithology, 2017. http://hdl.handle.net/11427/25053en_ZA
dc.identifier.citationOlinger, R. 2017. How does temperature affect Fork-tailed Drongo, Dicrurus adsimilis, foraging effort, nestling provisioning and growth rates?. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Olinger, Ryan AB - Global average temperatures are predicted to increase by as much as 5ᵒC by 2100. Therefore, it is imperative to identify how species are affected by temperature increase to ensure that proper conservation and management of wildlife can be implemented. Species which already live in warmer climates, such as deserts, may provide the first clues to the impacts of increasing temperatures. Birds represent an ideal indicator because research has shown that rising temperatures affect their behaviour, including foraging and provisioning of young, thereby reducing reproductive success. However, it remains unclear whether this results from physiological constraints on behaviour, from declining food availability and or access to prey items at high temperatures. In this study, I aimed to identify how temperature affects the foraging and provisioning behaviour of wild Fork-tailed Drongos, Dicrurus adsimilis, when supplemental food is provided. Additionally, I aimed to identify how nestling growth rates change with temperature. The results of two supplemental feeding experiments indicated that as temperatures increased, adults significantly reduced their willingness to forage, reduced provisioning to offspring and exhibited increased rates of heat dissipation behaviour. Furthermore, when provisioning nestlings, adult drongos consumed a larger proportion of supplementary food at higher air temperatures, and provisioned less. This suggests that they suffer greater provisioning costs at such times. Surprisingly, despite finding several negative effects of temperatures on adults' willingness to forage and provisioning, there was only a weak and non-significant effect of temperature on nestling growth rates. This suggests that adults may be able to compensate for reduced foraging at high temperatures. My study shows that the increased thermoregulatory costs of activity at high temperatures can constrain foraging and provisioning, even when food remains abundant. However, whether this impacts the fitness of current offspring or parents future reproductive success remains unclear. DA - 2017 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2017 T1 - How does temperature affect Fork-tailed Drongo, Dicrurus adsimilis, foraging effort, nestling provisioning and growth rates? TI - How does temperature affect Fork-tailed Drongo, Dicrurus adsimilis, foraging effort, nestling provisioning and growth rates? UR - http://hdl.handle.net/11427/25053 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/25053
dc.identifier.vancouvercitationOlinger R. How does temperature affect Fork-tailed Drongo, Dicrurus adsimilis, foraging effort, nestling provisioning and growth rates?. [Thesis]. University of Cape Town ,Faculty of Science ,Percy FitzPatrick Institute of African Ornithology, 2017 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/25053en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentPercy FitzPatrick Institute of African Ornithologyen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherConservation Biologyen_ZA
dc.subject.otherOrnithologyen_ZA
dc.titleHow does temperature affect Fork-tailed Drongo, Dicrurus adsimilis, foraging effort, nestling provisioning and growth rates?en_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
thesis_sci_2017_olinger_ryan.pdf
Size:
1.95 MB
Format:
Adobe Portable Document Format
Description:
Download
Collections
Masters