Land management for nightjars
4 November 2004
The nightjar is now a scarce breeding bird of lowland heathland, forest clearings and clearfells on suitable light soils throughout Britain, north to southern Scotland, and in coppice woodland in south-east England.
Nightjars were once much more numerous and widespread than today, but now appear to be recovering.
Extensive clear-fell harvesting in mature commercial forests planted after World War Two has produced large areas of new habitat and, simultaneously, conservation initiatives have restored much of the lowland heathland. Nevertheless, large parts of the former range remain unoccupied and the nightjar is still at risk from habitat change.
What do nightjars need?
Nightjars are summer visitors to the UK, arriving in mid-May. They usually raise two broods of one to two chicks in secluded patches of bare ground within low, often shrubby, vegetation, before migrating south in September or October.
Foraging is mainly at dusk and dawn, and through the night when they need to, on moths and other large flying insects, which they catch mainly on the wing. Although they feed over heathland and along forest rides and edges, nightjars are most successful when there is a range of food-rich habitats at hand. These include wetlands, such as reedbeds, fens, and grazing marsh, native woodlands, mature hedges, and old pasture.
'Foraging is mainly at dusk and dawn, and through the night when they need to, on moths and other large flying insects'
On lowland heathland, nests are usually located in small, naturally occurring gaps in deep heather in dry heath, with a
scatter of plant debris, but not live grasses. This offers shelter, camouflage and seclusion from potential predators. Scattered trees are used to sing from and to roost in.
In conifer forest clearings, clear-fells and restocks, especially on former heathland, the vegetation structure is like that of heathland, augmented with lying brash, which provides added concealment. Restocked clearings are abandoned as the tree canopy closes over the open ground around seven to eight years after planting, although these may be used if the crop is slow growing, for up to 12 years.
In coppice woods, nightjars nest in large recently cut coups (clearings), and continue to occupy them until the canopy covers much of the ground, in, for example, four to five years, depending on the rate of re-growth of the coppice.
There is increasing evidence to suggest that nightjars are vulnerable to disturbance, for example by dogs, which flush the adult from the nest allowing predators to take the eggs or chicks. Significantly, fewer chicks are raised to adulthood on sites with high levels of disturbance than on undisturbed sites.