The number of nightjar in Britain was in major decline after the Second World War. But now that we manage our public forests to protect wildlife, numbers appear to be increasing again. More than 50% of Britain's nightjar population now nest in woods where mature trees have been cut down and young trees planted. Nightjars are rarely seen during daylight, but at night when they are 'churring' on the branch of a prominent tree they can be picked out against the night sky.
Nightjar (Caprimulgus europaeus)
Nightjars migrate to Britain from Africa and return there after rearing their chicks. They arrive in the south of England, their main stronghold, in April and in the north of England and central Scotland in May and early June. Nightjar traditionally nest in lowland heath. They prefer areas with scrubby vegetation and the occasional taller tree to 'churr' from, and usually avoid moorland managed for red grouse and sheep. Adult pairs need a minimum of 2 hectares to nest, but they may fly 2-3 kilometres to feed. Nightjar also like forestry plantations, nesting on 'clear fell' sites - where all the trees have been cut down - and on replanted areas, until the trees are around 15 years old. These new heaths provide good nesting cover, plenty of perches and an abundant food supply. At night, radio-tracked birds have been recorded leaving their territories to feed in other habitats, such as deciduous woodland and wet pasture.
Nightjar first breed when they are 1 year old. Nesting begins in May in the south of Britain and in late May/June in the north. There are usually 2 eggs in a clutch, and between 1 and 2 birds survive to leave the nest.
Young nightjars become independent just over 1 month after hatching.
Nightjars feed mainly on the larger moths. They arrive in Britain in late spring and early summer when the moth population explodes. They are most active at the same times of day as moths, at dawn and dusk.
Like many ground nesting birds, nightjars have their nests attacked by predators such as foxes and stoats, and crows and magpies. Adders use nightjar nest platforms for basking and take eggs and small young birds. But these predators do not pose a serious threat to a successful breeding population. The main threat to the species comes from loss of habitat - a reduction in the area of lowland heath or changes in forestry practice that do not recognise the importance of clear felled and replanted forest. Moths can also be affected by pesticide use and a major reduction in moth numbers will affect the nightjar population.
Nightjars are rarely seen during daylight. They remain motionless on the ground, relying on their amazing camouflage - feather patterns that look like dead leaves and old tree bark - to avoid detection. But at night when they are 'churring', they usually perch on the branch of a prominent tree and can be picked out against the night sky. When flying, nightjar swoop and flap around their territories, often coming very close to any observers. Males have prominent white markings on the wings and tail, and females have brown markings that are much less prominent. These stand out even at night, so it is often possible to identify the bird's sex. People most often encounter the nightjar's distinctive sound. Males perform a prolonged churring call ('nightjar' means night-churr) that may go on for several minutes, varying in pitch and volume. Hear the call here. When the birds stop churring, they are often in flight and two other sounds are frequently heard. The first is a rather soft 'coohwick' given as a single note and thought to be a contact call. The second is a slapping or hand-clapping sound caused as the birds clap their wings in flight
How we manage our woods
All Forestry Commission woods have design plans. These help us create long-term objectives and targets for the future. With the help of local enthusiasts, we are able to identify forests where nightjars occur and make sure that plans allow for a sequence of clear felling and replanting, providing suitable habitat and food supply.
Did you know?
We name our bird 'nightjar' from its call. In the US, a close relative singing a different song is called the 'whip-poor-will'.