Harvest mice are rarely seen but easily recognised. Presence is most easily confirmed by the characteristic summer nests.
Breeding nests are spherical, tennis ball-sized or slightly smaller, neatly woven using relatively long
strips of grass, and attached to the grass stalks.
Non-breeding nests are smaller and often more elongated. In tall grasses, nests are sited in the stalk zone. In tussocky grasses they are usually sited at the base of the tussock or occasionally on the side.
Field Vole nests are often larger, are not woven into grass stalks and tend to be more amorphous in shape.
Some birds' nests may also be woven into grass stems but consist of an open cup rather than a closed ball.