Abstract
Hunting is a key source of disturbance which affects geese populations directly through killing and indirectly through shooting disturbance. Movements of individuals in response to hunting disturbance may expose geese to reduced feeding opportunities and higher predation risks, which can have consequences on the population level.
Thus geese should use habitats that provide access to food and minimize encounters with hunters. Our study focused on differences in the proportion of hunting-free area used and in the total area used by individuals, size of water bodies used by birds, and flight distance between roosting and feeding areas, during two periods before and after the start of the hunting season.
In south Bohemia (Czech Republic), in 2012, 2014 and 2015, we attached seventeen GPS/GSM-transmitters to moulting Greylag Geese Anser anser. We analysed data from nine transmitters, recording two or twelve logs per day, using minimum convex polygons home range estimates and Wilcoxon matched pairs test.
We showed that shortly after the opening of the hunting season, individual Greylag Geese used a significantly larger area and increased their roosting-feeding flight distances. These changes in local movements are likely linked with the start of hunting activity which relates to increased human disturbance in the study area.
In the post-breeding season, this may broadly affect the birds' energetic costs and ability to accumulate sufficient reserves for the upcoming autumn migration. However, we did not find a significant difference in the proportion of hunting-free (protected) areas used during our study periods.
This result, together with the observed decrease in numbers of Greylag Geese in south Bohemia in the second half of August, may be evidence of a lack of larger disturbance-free refuges in the study area.