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dc.contributor.advisorIms, Rolf Anker
dc.contributor.advisorJepsen, Jane Uhd
dc.contributor.advisorVindstad, Ole Petter Laksforsmo
dc.contributor.authorBjørkås, Ragnhild
dc.date.accessioned2017-06-09T11:26:50Z
dc.date.available2017-06-09T11:26:50Z
dc.date.issued2017-05-15
dc.description.abstractThe three box-nesting passerine bird species pied flycatcher, great tit and common redstart breed at their distributional limit in Troms, Northern Norway. Access to food and favourable weather conditions is expected to be of importance for the birds´ breeding population dynamics. In the same area, geometrid moth larvae experience cyclic population outbreaks at approx. 10 year intervals, constituting a superabundant and potentially important source of food for insectivorous birds during the breeding season. To assess if the birds´ breeding population dynamics could be explained by moth larval densities and summer temperatures, we conducted yearly inspections of nest box occupancy and moth larval counts during a period of 13 years at 12 study sites, and obtained temperature measurements from nearby weather stations. Results from GLMM models with a logit link function suggested a moderate positive numerical response of the bird community to high moth larval densities. The response was species specific, with the great tit showing the most consistent response – indicating that this species is probably more dependent on moth larvae during breeding season than the other two bird species. The bird community also showed a positive numerical response the year after high summer temperatures, likely because it caused higher breeding success and subsequent higher return rates of breeding birds. It was concluded that the focal bird community was positively affected by high moth larval densities and summer temperatures, but that other factors were probably also limiting on breeding population densities due to the moderate response.en_US
dc.identifier.urihttps://hdl.handle.net/10037/11135
dc.language.isoengen_US
dc.publisherUiT Norges arktiske universiteten_US
dc.publisherUiT The Arctic University of Norwayen_US
dc.rights.accessRightsopenAccessen_US
dc.rights.holderCopyright 2017 The Author(s)
dc.rights.urihttps://creativecommons.org/licenses/by-nc-sa/3.0en_US
dc.rightsAttribution-NonCommercial-ShareAlike 3.0 Unported (CC BY-NC-SA 3.0)en_US
dc.subject.courseIDBIO-3950
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480en_US
dc.subjectFicedula hypoleucaen_US
dc.subjectParus majoren_US
dc.subjectPhoenicurus phoenicurusen_US
dc.subjectOperophtera brumataen_US
dc.subjectEpirrita autumnataen_US
dc.subjectAgriopis aurantiaria,en_US
dc.subjectMoth larvaeen_US
dc.subjectTemperatureen_US
dc.subjectBreeding population dynamicsen_US
dc.subjectNumerical responseen_US
dc.subjectVDP::Mathematics and natural science: 400::Zoology and botany: 480en_US
dc.titleSpatio-temporal dynamics in breeding occurrence of passerine birds in subarctic birch foresten_US
dc.typeMaster thesisen_US
dc.typeMastergradsoppgaveen_US


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Attribution-NonCommercial-ShareAlike 3.0 Unported (CC BY-NC-SA 3.0)
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