The Arctic Fox Dilemma
Today I received a picture of two arctic foxes, resting in the dim morning light on Spitsbergen. The picture awakes an emotional conflict. I like the foxes a lot but hope they will starve....
I am studying geese, but I am faced with an increasing predation pressure of foxes. Since the start of my field study in 1990, there have been several years without polar foxes in the study area. In these years all birds are doing well and increase in numbers. When polar foxes are present, there are very few young birds surviving. In the past six years with an increasing predation pressure of foxes, the goose population has become half of what it was.
The arctic fox is well adapted to the harsh winter conditions. There is not much food. Rodents are lacking on Spitsbergen and the foxes have to survive most of winter from there food caches. The end of winter is the most difficult period, in which ice can help them to survive.
They can follow polar bears on the ice and feed on the remains of the polar bear prey. Or they can hunt for new-born seal puppies in early spring. On the tundra, there is no prey to hunt. In some years a die-off of reindeer can provide food. This happens especially in warm winters when a layer of ice covers the tundra and makes the vegetation inaccessible for the reindeer.
So far, there is no ice on the fjord or on the tundra. I would predict a difficult winter for the foxes and hence a beautiful summer for the birds without this predator. But than I received this photo…
You can read more about foxes and geese on my Arctic Station weblog.
Text and photos by Marten Loonen.
Please visit the Bird Health website to learn more about the IPY project that Marten is working on