Home / Environment / Island Mice Vanish After Humans Leave St Kilda
Island Mice Vanish After Humans Leave St Kilda
15 Sep
Summary
- St Kilda's house mouse went extinct within 18 months of human departure.
- Field mice expanded into abandoned buildings after humans left.
- Competition with field mice likely caused house mouse extinction.
The remote Scottish archipelago of St Kilda witnessed a unique ecological event following the evacuation of its last human residents in 1930. Within approximately 18 months, the St Kilda house mouse, closely linked to human habitation, became extinct. This disappearance was linked to the departure of the islanders, which fundamentally altered the mice's environment.
Before the evacuation, St Kilda supported two distinct mouse populations: the St Kilda house mouse (Mus musculus muralis) and the St Kilda field mouse (Apodemus sylvaticus hirtensis). The house mouse relied heavily on human-provided shelter and stored food, thriving within the settlement. Conversely, the field mouse, though established, was less dependent on human structures.
Upon the islanders' departure, the established field mice began to occupy the vacant human dwellings. Researchers suggest this expansion into formerly house mouse-dominated territories, coupled with intense competition for resources, led to the house mouse's extinction. The absence of humans removed the structural advantage that house mice had previously enjoyed, tipping the survival balance.
Subsequent research indicated that while some house mice survived initially due to remaining food supplies, competition with the field mouse was the more probable cause of their demise. The field mouse, a larger subspecies of wood mouse, continues to inhabit St Kilda, remaining common on Hirta and present on Dun.
