Noctule bat (Nyctalus noctula)

What do noctule bats look like?

The largest bat in Britain, the noctule measures 4-5cm in length and weighs up to 40g. It has golden-brown fur with a darker brown face and wings. Its small, rounded ears are also dark brown and have a mushroom-shaped tragus, the bit of flesh in front of the ear canal.

What do noctule bats eat?

The noctule bat’s diet is made up of insects; particularly moths, winged ants, midges and flying beetles. It hunts at night, although it may emerge before dark during the summer months. It catches its prey on the wing, using its powerful flight to dive and catch insects from above the tree canopy.

How do noctule bats breed?

The breeding season for noctule bats takes place towards the end of summer. Some males form groups while others are solitary. The male finds a tree hole to be his mating roost and attempts to attract a mate using a range of shrill calls and by producing a strong odour during flight. Males will often mate with several females.

Maternity colonies are not formed until the following spring when both males and females begin to nest in tree holes, crevices in buildings and nest boxes. Females give birth to one pup during late June or July, and the pup is usually independent after six weeks.

Where do noctule bats live?

Noctule bats are woodland inhabitants, living in the rot holes in trees as well as woodpecker holes. They are widespread in England and Wales, with some numbers in south-west Scotland.

Signs and spotting tips

Head to the woods just before dark for the best chance of seeing this species. Noctule bats are high flyers, flying above the tree canopy, so keep your eyes to the sky to catch sight of one. See if you can spot them repeatedly diving in the sky as they hunt their insect prey.

Threats and conservation

While the noctule bat is widespread in the UK, it is thought the population may have declined following the introduction of intensive farming methods. It is also vulnerable to the loss of mature trees, which it uses as nesting and hibernation sites. The noctule bat is classified as a priority species in the UK Biodiversity Action Plan. It is also protected by law in the UK under the Wildlife and Countryside Act 1981.