Sökning: "foraging behavior"
Visar resultat 1 - 5 av 10 avhandlingar innehållade orden foraging behavior.
1. Costs of foraging in a dry tropical environment
Sammanfattning : This study evaluates the costs associated with foraging for birds in a savannah woodland area in central Nigeria. Specifically, it looks at the following questions: 1) how does seasonal variability in food and water availability affect the value of resources to birds in dry environments? 2) Does proximity to water affect foraging decisions? What implication will this have in the management of savannah birds? 3) Are tropical birds mostly affected by metabolic or predation costs? 4) What factors affect diet selection in birds and how? 5) How are birds adapted to hot dry environments? I carried out experiments in the field and in an aviary and provided artificial food patches, consisting of feeding trays with seeds mixed in sand or pebbles (in the aviary study). LÄS MER
2. Bee foraging and pollination : Consequences of spatial and temporal variation in flower resources
Sammanfattning : Wild bees foraging in contemporary agricultural landscapes are, because of agricultural intensification, faced with the challenges of reduced flower-rich habitats, as well as a changed spatio-temporal distribution of flower resources. As a result of this and other stressors such as pesticide exposure, widespread declines of bees have been reported. LÄS MER
3. Food hoarding: Memory and social conditions - an evolutionary approach
Sammanfattning : Food hoarding is a widespread behavior among a large number of animals, and it exists in several different varieties, all of them used by the animals as a method of having a steady supply of food during periods of low food abundance such as the winter. This thesis concentrates mainly on two aspects of scatter food hoarding behavior, using small birds as study and model animals. LÄS MER
4. Forest – stream linkages : Brown trout (Salmo trutta) responses to woody debris, terrestrial invertebrates and light
Sammanfattning : Forests surrounding streams affect aquatic communities in numerous ways, contributing to energy fluxes between terrestrial and lotic ecosystems. The five papers in this thesis focus on woody debris, terrestrial invertebrates and light, three factors influenced by riparian zone structure, potentially affecting streams and brown trout (Salmo trutta). LÄS MER
5. Forest-stream linkages : Experimental studies of foraging and growth of brown trout (Salmo trutta L)
Sammanfattning : Riparian vegetation along streams and rivers affects the aquatic community in numerous ways and often operates as a link for energy flux between forest and streams. The studies presented in this licentiate thesis focus on light and terrestrial invertebrates, two factors influenced by riparian zone structure, which potentially affect stream ecosystems and thus also brown trout (Salmo trutta). LÄS MER
