Every bit of bush in New Zealand harbours house mice (Mus musculus), sometimes in plague numbers. By eating insects and fallen seeds and berries, mice deprive many native ground-feeding animals of food.
The house mouse is a small mammal, characteristically having a pointed snout, small rounded ears, and a long naked or almost hairless tail. Although a wild animal, the house mouse mainly lives in association with humans.
Ship Rats or Black Rats
Europeans brought ship rats (Rattus rattus), also known as black or roof rats, but these did not become established until after the 1860s.Despite the name, these rats are usually neither black nor associated with ships.
The species originated in tropical Asia and spread through the Near East in Roman times before reaching Europe by the 1st century and spreading with Europeans across the world. It is the most common rat in New Zealand.
Black rats are generalist omnivores. They are serious pests to farmers as they eat a wide range of agricultural crops.
Norway Rats (Brown)
Norway rats (Rattus norvegicus), also known as brown or water rats, were on the ships of the first explorers, who arrived in New Zealand in the late 1700s. These rats quickly spread.
Thought to have originated in northern China, this rodent has now spread to all continents except Antarctica, and is the dominant rat in Europe and much of North America—making it by at least this particular definition the most successful mammal on the planet after humans. With rare exceptions, the brown rat lives wherever humans live, particularly in urban areas.