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Publication type: Master thesis
Title: Influence of human encounters on movement of blackbirds (Turdus merula) in hedgerows
Authors: Scherl, Daniel
Advisors / Reviewers: Graf, Roland Felix
Jenni, Lukas
Jenni-Eiermann, Susanne
DOI: 10.21256/zhaw-20663
Extent: 27
Issue Date: 2018
Publisher / Ed. Institution: ZHAW Zürcher Hochschule für Angewandte Wissenschaften
Publisher / Ed. Institution: Winterthur
Language: English
Subjects: Human disturbance; Recreation; Flying distances; Movement events; Radio-telemetry
Subject (DDC): 590: Animals (Zoology)
Abstract: Outdoor recreation is increasing in intensity and space. Areas previously inaccessible are now being visited by ever-growing numbers of people, which increases human-wildlife encounters across taxa. Animals often perceive humans as predators and mount physiological and behavioural responses that can have negative consequences. Human disturbances, even at low levels, are likely to impact species during sensitive breeding season in a sex- and status-specific way. However, experimental studies on movement behaviour for the same individual during consecutive days are lacking. Here, we experimentally disturbed blackbirds in hedgerows over several days and quantified their flying distances and movement events using radio-telemetry. We compared the movement before, during and after a disturbance using linear mixed effects models (LME). We showed that Blackbirds of unknown status increased their flying distances during disturbance to the non-disturbed periods directly before and after (+95.5 m/10min / +114 m/10min) and showed a strong tendency to increase numbers of movement events. Contrary to our expectations, we did not find a clear long lasting effect despite the trend that females with unknown status remained at the same flying distances as during disturbance. For feeding blackbirds we found a sex-specific tendency that females reduced flying distances while males moved more during disturbance. In general, incubating females moved little with preferences for short distance movement. Furthermore, we wanted to investigate whether birds which were not accustomed to human encounters get habituated or whether they become sensitized during disturbance series. The sample size was too small to draw conclusions, but the data showed a tendency indicating a sensitization. The flying distances increased for during disturbance (experiment 6) and also for after disturbance (experiment 5 and 6) period. Additionally, trees had a pronounced positive effect on flying distances for either flying distances or movement events. We observed sex- and status-specific responses of blackbirds to human encounters disrupting their daily routine behaviour. These findings suggest, that further studies should incorporate sex-, status- and also personalities of individuals investigating the negative impact on fitness parameters of the parents and/or the nestlings. In addition, the sensitization trend of blackbirds to human encounters must be proved, especially for not accustomed individuals over a couple of days. Moreover, visitor guidance and prevention of trail construction in undeveloped semi-natural habitats would reduce impact on modified movement pattern thru recreationists most efficiently.
License (according to publishing contract): CC BY 4.0: Attribution 4.0 International
Departement: Life Sciences and Facility Management
Appears in collections:Masterarbeiten Umwelt und natürliche Ressourcen

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