Rats are commensal rodents the numbers of which are influenced by our activities, buildings and the landscape we have created. The type, style age and size of our houses and gardens and what we do in them will impact on
the number of rats. Some activities such as keeping chicken, feeding the birds and composting using an open heap may be beneficial to the rats while others such as keeping cats or terriers may discourage them.
The main rat
species in England is the Norway or brown rat, Rattus norvegicus. The Black rat, R. rattus, associated with the bubonic plague is less common in the UK being mainly restricted to ports or coastal towns where they forage in disused
buildings and warehouses but thy are found in larger numbers elsewhere.
Rat tunnels in the soil or at the base of the compost bin are often the first sign of infestation. The tunnels entrance is about 30-40mm diameter. may be visible
where damage has occurred.
Although many gardeners and composters will only see rats infrequently, if at all, a study conducted in central New York reported that pests, including rats, were the third most common obstacle
to home composting (Tompkins County Compost Study. Prepared by: Cornell Cooperative Extension’s Compost Education Program 2001). Undoubtedly opening a bin to find a rat sitting on the composting looking at you can be a disconcerting even if it only happens
once. While rats may visit, or nest in, a compost bin if they are already present in the area composting does not generally attract the rats in the first place.
When rats are feeding, sheltering or nesting in
a compost bin burrows can often be seen under the bin or holes are visible chewed into the side of the bin. The signs of their presence in the rest of the garden are also relatively easy to detect
The Norway rat creates
burrows and makes “rat runs” along building foundations, garden fences and walls. They will also burrow beneath chicken houses, woodpiles, manure and compost heaps. Nests in compost heaps or bins may be lined with shredded paper, other dry material
from the heap or material brought into the bin. The contents of the compost bin make a good restaurant for brown rats as their preferred diet includes cereal grains, nuts, and fruits, meat and fish.
The Black rat seldom
digs burrows preferring to nest in locations off the ground in dense vegetation, shrubs, trees, vines etc. They also eat a range of foods that might be found in the compost bin. There preferred diet consisting of fruits, nuts, berries, slugs, and snails.