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Title: | The role of breeding experience on the foraging specialization of a pelagic marine predator, the Cory's sheawater | Authors: | Haug, Fredrik Duvholt | Orientador: | Paiva, Vitor Ramos, Jaime |
Keywords: | Aves; Procura de alimentos | Issue Date: | 2012 | Citation: | HAUG, Fredrik Duvholt - The role of breeding experience on the foraging specialization of a pelagic marine predator, the Cory's shearwater. Coimbra : [s.n.], 2012. Dissertação de Mestrado em Ecologia. | Place of publication or event: | Coimbra | Abstract: | Experience is believed to be an important factor determining the foraging
success of animals, but there are still very few studies investigating how foraging
abilities develop over time. In this study, the spatial distribution and foraging tactics
of inexperienced and experienced individuals of a Procellariiform seabird species, the
Cory’s shearwater (Calonectris diomedea borealis) breeding on the Portuguese
continental shelf was compared. Kernel analysis and a multivariate analysis
(MADIFA) showed that while the experienced birds were relying on known static
features such as the bathymetry of the area, inexperienced birds were using larger
areas that were explained by different static and dynamic variables each year. The
foraging areas of the two groups overlapped less and less for each year, while stable
isotope signatures were becoming more and more similar, as inexperienced birds were
foraging on higher trophic prey closer to the coast, like the experienced birds. Linear
mixed models comparing home ranges and foraging areas calculated for each group
showed that the experienced birds were in general more successful in detecting
favourable foraging grounds, except in 2011, when the results showed the opposite.
Interestingly, the reproductive success of the inexperienced birds was significantly
higher than for experienced birds during that season. A experiência é considerada um factor importante para o sucesso de procura de alimento dos animais, mas há ainda muito poucos estudos que investiguem como as habilidades de procura de alimento se desenvolvem ao longo do tempo. Neste estudo, foi comparada a distribuição espacial e as tácticas de procura de alimento de indivíduos experientes e inexperientes de uma espécie de Procellariiforme, a cagarra (Calonectris diomedea borealis), cuja população se reproduz na plataforma continental Portuguesa. A análise de Kernel e uma análise multivariada (MADIFA) mostrou que, enquanto as aves experientes dependiam de variáveis estáticas, tais como a batimetria da área, as aves inexperientes utilizaram áreas mais vastas respondendo em cada ano, a diferentes variáveis estáticas e dinâmicas. Os modelos lineares mistos comparando as características de habitat nas áreas de utilização com as áreas de procura de alimento entre ambos os grupos, mostraram que geralmente as aves experientes têm mais sucesso na detecção de locais de procura de alimento mais favoráveis, excepto em 2011, quando os resultados mostraram o oposto. Curiosamente, o sucesso reproductor das aves inexperientes nesse ano foi superior aquele das aves experientes. |
Description: | Dissertação de Mestrado em Ecologia, apresentada ao Departamento de Ciências da Vida da Faculdade de Ciências e Tecnologia da Universidade de Coimbra. | URI: | https://hdl.handle.net/10316/30823 | Rights: | openAccess |
Appears in Collections: | UC - Dissertações de Mestrado FCTUC Ciências da Vida - Teses de Mestrado |
Files in This Item:
File | Description | Size | Format | |
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MASTER_THESIS_ECOLOGY_FREDRIK_HAUG.pdf | 38.13 MB | Adobe PDF | View/Open |
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