Marinde Out

PhD Candidate

Senior Supervisor: Ronald C. Ydenberg


Ronald C. Ydenberg
Bernard D. Roitberg

Thesis Title

Flyway of fear or famine: why are geese changing migration strategies?

Research Interests

am passionate about the network between animal species and individuals. Predator-prey interactions excite me the most, because there is tension between two players, tension that might define life or death. Look how the cat stalks the prey, even if it’s a toy ball. This hunting cat can turn in coyote prey as well, and all those poor song birds that are being stalked by the cat actually are ferocious insect hunters. Nothing is set in stone. Besides predator-prey interactions I am also interested in communication between an within species. For example, the interactions between scavengers and hunters, communication within bird flocks, and politics in corvid groups (birds of the crow family).

Predator-prey interactions are rarely implemented in conservation plans. This surprises me, because predators have a great influence on the whereabouts of their prey. Without top predators, there are no limits where and when prey can forage. For example, irruptions of goose and wild boar populations cause increasingly more traffic accidents and agricultural crop damage in areas without predators like the Netherlands. My research interest is to find supporting evidence that predation is no negative factor in an ecosystem, but a catalyzing factor. Can prey irruptions be stabilized when predators re-colonize their former hunting grounds?

Current research

My Ph. D. research is directly related to the effect of predators on prey irruptions. Are returning sea eagles changing the migration behavior of Arctic-breeding geese? Since the 1990s, barnacle geese (Branta leucopsis) started to delay their spring migration departure from the Netherlands. This delay coincides with the recovery of white-tailed eagle (Haliaeetus albicilla) populations in North-eastern Europe, for example around the Baltic Sea. In North America, bald eagles (Haliaeetus leucocephalus) have also increased in numbers. Are black brant geese (Branta bernicla nigricans) responding to the increased predation danger along their migration routes? Which other factors play a role? I am studying these changes by conducting fieldwork in the Netherlands, Estonia and British Columbia.