These days nature conservation organizations buy agricultural fields and pastures and change them into nutrient poor, ecological favorable, nature areas in order to increase the biodiversity and the reoccurence of species of historical importance. These areas used to contain flourishing populations of earthworms because of the ideal environment which was created by frequent use of manure by farmers. In Western and Eastern Europe, earthworms are the major food source in the badgers diet. Several studies show a specialist worm feeder for which earthworms comprise over 50% of the diet. The badgers frequently visit earthworm-rich short pastures mainly in search for the larger worm species Lumbricus terrestris which, depending on climate and microclimate, comes to the surface to feed during so-called “worm nights”.
Because of the disappearance of agricultural areas in close proximity of badger setts the earthworm availability decreases. It is suggested that the disappearance of these feeding sites has a negative effect on badger numbers which is in line with the resource dispersion hypothesis. It was found that with an increase in earthworm biomass, badger numbers increase and with a decline in earthworm populations the badger show a decrease in consumption, that badgers lose weight, increasingly eat less favored food and availability affects breeding success. Badgers in several occasions seem to compensate for a decline in or fluctuations of earthworm availability by switching to other food sources. It depends on the feeding strategy of the Dutch badgers, if a long term decline in earthworms will have an effect on the dynamics of (local) badger populations.
The objective of this study is to get insight in the effect of resource density on the feeding strategy of the Dutch badger by quantifying the badgers diet in a high and low quality habitat.