Common hamster: trends in numbers

Changes in farming practice led to the virtual extinction of the common hamster in the Netherlands. It was reintroduced in a protected area in south Limburg in July 2002.

Trends

The hamster used to occur in the Netherlands in fields of cereals or root crops on loess and loam soils. In the 1940s it was still seen as a pest in the fields of Limburg. In the period 1970-1993 it was present in 259 1 x 1 km grid squares, but by 1994-1997 it was present in only 137 grid squares. Since 1994 the number of hamster warrens has fallen even more (see figure). Some say that the species disappeared from the Netherlands in 2001, when the field with the last warrens was ploughed over, but others say that in that year the species was present in a few other places.

A species protection plan for the common hamster was drawn up in 2000, its aim being to assure the sustainable existence of the species in its natural habitat. The first step to achieve this aim was to breed animals for release in protected areas. The first animals from this project were released in a field in Sibbe in 2002.

Causes

The most important cause of the decline is the loss of suitable habitat caused by cereal fields being converted to grass, maize and woodland. The fragmentation of the remaining habitat has also reduced the chance of survival. Furthermore, efficient harvesting techniques mean that less grain is left on the fields after harvest and therefore the hamsters cannot collect and store sufficient. And hamsters will also eat the poisoned bait scattered on field margins to control mice.

Attempts are being made to protect the species by designating reserves and by concluding management agreements with farmers.

The common hamster is on the Red List of mammals. Its numbers are also falling sharply in Belgium and Germany.