Rats and mice produce many droppings. Mice will produce up to 80 a day. It is often these droppings that are the first sign of an infestation of rats or mice. It is possible to identify the species from the appearance of the droppings.
There are four species of pest rodent in New Zealand. The Mouse (Mus musculus) and rats; the Roof Rat (Rattus rattus) also known as the Ship Rat and Black Rat, the Norway Rat (Rattus norvegicus) also known as the Water Rat, and the Kiore (Rattus exulans) also known as the Pacific Rat.
You are unlikely to be able to examine the rodent closely and it is often only the evidence of droppings that you have to identify your infestation. The size and shape of these dropping can be a good indication of what rodent you have. The image below may help you identify the rodent from the dropping you find.
The main difference between the droppings of the three common rodent pests is size. Mice droppings are small (4-7mm), rat droppings are larger, roof rats (7-14mm) and Norway rats (14-19mm). They also differ in the shape of the end of the droppings; Norway rat droppings are rounded while mice and roof rat droppings are pointed.
Note that droppings change a little as they dry out. If the droppings are soft and moist this suggests that they are recent and suggest active infestation.