Urban geese discriminate between predators of different sizes

Abstract

Compared to rural areas, the density of predators such as domestic Dogs Canis lupus familiaris is high in urban areas. Greylag Geese Anser anser recently colonised the city of Stuttgart, southwestern Germany where they frequent large public parks that offer rich grazing for these herbivores. People regularly walk their dogs within the parks, which often disturb the geese and provides an opportunity to study the anti-predator behaviour of Greylag Geese to these potential predators. Goose response distances and strength increased with dog size. Small dogs, people without dogs and vehicles resulted in much shorter response distances. Since large dogs can easily kill geese, it may be adaptive for the geese to fine-tune their behaviour to the real danger from domestic predators.