Abstract

Lethal scaring is one method used to alleviate crop damage by grazing geese. During lethal scaring, a few geese foraging on growing crops are shot to achieve a deterrent effect on other flock members. An additional aim is to reinforce the effects of non-lethal scaring measures. As the populations of geese increase in large parts of the world, an increased need for tools within the multifaceted area of goose management has been highlighted. Lethal scaring can potentially be one method, but currently little evidence exists about the effectiveness of the method.In this study, I tested whether grazing greylag geese Anser anser show short-term numeric and behavioral responses due to lethal scaring in targeted fields, using a Before-After-Control-Impact (BACI) study design. The study includes 26 fields with lethal scaring and 43 controls (geese were left undisturbed), where the number of birds was counted and the distance between an approaching person and the geese when all individuals have raised their heads and when they escaped were measured - before and after lethal scaring was performed.On average, 33 geese were shot per trial, which corresponds to 8.9% of the counted geese on the lethal scaring fields before the shooting occurred. The number of geese significantly decreased in the lethal scaring fields after the shooting (63% less) but were also reduced in numbers on the control fields (17% less). This result may be due to the same goose individuals using both control and lethal scaring fields, and when affected at scaring fields they choose another area or habitat for foraging; for example, in wetlands. However, the difference in the number of geese on control fields, both before and after lethal scaring, did not relate to the distance to lethal scaring fields. Moreover, birds did not seem to become more afraid of an approaching person (i.e., a non-lethal scaring tool) after the lethal scaring had been conducted (flight distance before 134 m (+/- 15.3 S.E.) and after 149 m (+/- 14.1 S.E.) in lethal scaring fields).In conclusion, this study shows that lethal scaring can substantially decrease the number of greylag geese in damage prone fields for at least three consecutive days, hence this method may also work as a tool to reduce crop losses. Practical experience from tools for alleviating crop damage is available from both Europe and North America, but very little has been published. It is therefore important to evaluate the effectiveness of the available tools under controlled conditions to increase our understanding of appropriate preventive tools and provide guidelines for stakeholders involved in the multifaceted area of goose management and crop protection. (C) 2017 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Keywords

Birds; Geese; Crop protection; Harvest losses; Management; Preventive measures

Published in

Crop Protection
2017, Volume: 96, pages: 258-264
Publisher: ELSEVIER SCI LTD

SLU Authors

• Månsson, Johan

  • Department of Ecology, Swedish University of Agricultural Sciences
    

Associated SLU-program

SLU Plant Protection Network


UKÄ Subject classification

Agricultural Science
Ecology


Publication identifier

DOI: https://doi.org/10.1016/j.cropro.2017.03.001

Permanent link to this page (URI)

https://res.slu.se/id/publ/82530