Reducing the number of grazing geese on agricultural fields - Effectiveness of different scaring techniques

Abstract

Scaring is a widely used damage mitigation tool to make agricultural fields less attractive to wildlife and by that reduce crop damage. However, few experimental studies exist where the numerical response of different scaring devices has been compared. We tested experimentally the effect of three different scaring devices (kite, scarecrow, inflatable man) on the number of geese in fields with cereals, ley, rapeseed, potatoes, and carrots in Sweden. Geese were counted by camera traps and two approaches were used; in a first (model 1) only geese within 50–150m of the scaring devices were counted, and in a second (model 2) all geese in the field were included. A total of 42,281 geese were counted: Greylag goose Anser anser was the most common species (87%), followed by bean goose Anser fabalis (6%), greater white-fronted goose Anser albifrons (3%), barnacle goose Branta leucopsis (2%), and Canada goose Branta canadensis (2%). During scaring the number of geese significantly decreased for all three devices in model 2. The inflatable man decreased goose numbers by 90.0 %, scarecrow 64.6%, and kite 60.5%. A similar pattern was found in model 1, but the decrease was not significant. Our study shows that the scaring devices studied can reduce goose grazing pressure for some time and locally. However, since geese continue to graze during scaring, we conclude that scaring alone is not a final solution to mitigate crop damage. Future work to develop more effective control measures should address the efficiency of other management tools and scaring techniques in combination.