Square-tailed Nightjar (Caprimulgus fossii)

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Image of a Square-tailed Nightjar in its natural habitat
Birds Nightjar

Introduction

The Square-tailed Nightjar, Caprimulgus fossii, is a nocturnal member of the nightjar family, Caprimulgidae. It occurs mainly in sub-Saharan Africa, where its cryptic plumage, ground-nesting habit and aerial insect-catching behaviour help it remain concealed by day and active after dusk. The species is also known as the Mozambique Nightjar in parts of southern Africa.

Physical Description

The Square-tailed Nightjar is a medium-sized nightjar, measuring approximately 23–24 cm in length. Its plumage is predominantly mottled greyish brown, buff and dark brown, providing effective camouflage against sandy soil, leaf litter, dry grass and woodland floors.

The tail is relatively broad and appears square-ended compared with the more obviously elongated or forked tails of some related nightjars. The wings are long and pointed, and the bill is short but broad, with conspicuous rictal bristles around the mouth. These bristles are associated with the capture of flying insects.

Males and females are similar in overall appearance. Males generally show more clearly defined white markings in the wing and tail, while females tend to have corresponding markings that are duller or more buff-toned. Juveniles are usually more heavily streaked and less sharply marked than adults.

Range and Habitat

The Square-tailed Nightjar has a broad Afrotropical distribution. It occurs from western Gabon and adjacent parts of the Congo Basin eastwards through central and eastern Africa, and southwards through Zambia, Zimbabwe, Mozambique, Botswana, Namibia and eastern South Africa. Its distribution and seasonal movements vary between regions and subspecies.

It is associated mainly with lowland and foothill wooded grassland, savanna, miombo and mopane woodland, thornbush and other open habitats with scattered trees or shrubs. It generally requires areas of relatively open ground for roosting and nesting, including sandy, gravelly or lightly vegetated surfaces. It may also occur in cultivated or disturbed landscapes where suitable open habitat remains.

Some populations make seasonal or local movements, apparently influenced by rainfall and the availability of suitable feeding and nesting conditions. The species is not regarded as a long-distance migrant across its entire range.

Behaviour and Diet

The Square-tailed Nightjar is mainly nocturnal, becoming active around sunset and continuing to forage through the night. It often hunts from a low perch, such as a dead branch, stump or small tree, and makes short sallies to capture insects in flight. It may also feed around lights or fires where insects have gathered.

Its diet consists mainly of flying insects, including beetles, moths, grasshoppers, termites, bugs, flies, ants and other small invertebrates. The wide gape and rictal bristles help it take prey during aerial pursuits.

The species usually nests directly on the ground, without constructing a conventional nest. One or two eggs are laid in a shallow depression on sand, fine gravel, bare soil, dry leaf litter or another naturally suitable surface. In southern Africa, laying has been recorded mainly from late winter through spring and early summer, although timing varies geographically.

Incubation is carried out largely by the female and lasts approximately 14–17 days. The young are mobile soon after hatching and remain dependent on the adults while they develop their flight and feeding abilities. Camouflage is important throughout the breeding cycle: both the incubating adult and the eggs can closely match the surrounding substrate.

Identification Tips

  • Look for a medium-sized, cryptically patterned nightjar in open woodland, savanna or sandy bush country after dusk.
  • The broad, relatively square-ended tail is a useful structural clue, although the tail may not appear completely square in flight.
  • The plumage is generally greyish brown, buff and darkly mottled, with pale markings in the wings and tail that may be difficult to see except in good light or during flight.
  • It is often detected first by its activity at dusk, low-perched hunting behaviour or distinctive nightjar calls rather than by a prolonged view of the bird.
  • In southern Africa, careful comparison may be required with the Slender-tailed Nightjar, Caprimulgus clarus, and other similarly cryptic nightjars. The Square-tailed Nightjar generally lacks the clearly projecting central tail feathers that give the Slender-tailed Nightjar its characteristic appearance.

Conservation Status

The Square-tailed Nightjar is currently assessed as Least Concern on the IUCN Red List. Its extensive distribution and occurrence in a range of woodland and savanna habitats support this assessment. A precise global population estimate and a robust continent-wide population trend are not available.

Local populations may be affected by habitat conversion, woodland degradation, agricultural expansion, disturbance of breeding sites and changes to the open ground required for nesting. Because the species is widespread and can use some modified habitats, these pressures are not currently considered sufficient to place it in a threatened category. Maintaining connected savanna and woodland habitats, protecting areas used for breeding and improving monitoring of nocturnal birds remain appropriate conservation measures.

Frequently Asked Questions

Where does the Square-tailed Nightjar live?

It occurs across much of sub-Saharan Africa, from western and central Africa through eastern Africa and southwards into southern Africa. It is associated mainly with savanna, miombo and mopane woodland, wooded grassland, thornbush and open areas with scattered vegetation.

Is the Square-tailed Nightjar migratory?

It is not a uniform long-distance migrant, but some populations make seasonal or local movements. These movements may be linked to rainfall, food availability and changes in habitat conditions.

What does the Square-tailed Nightjar eat?

It feeds mainly on flying insects, including beetles, moths, grasshoppers, termites, flies, ants and other small invertebrates caught during short aerial sallies.

Where does it build its nest?

It does not usually build a nest. One or two eggs are laid directly on the ground, often in a shallow depression on sand, gravel, bare soil, dry leaf litter or lightly vegetated ground.

How can the Square-tailed Nightjar be identified?

Useful clues include its medium size, mottled grey-brown and buff plumage, broad square-ended tail, open woodland or savanna habitat and low-perched insect-hunting behaviour after sunset. Its call is also important because visual sightings are often brief.

Is the Square-tailed Nightjar endangered?

No. The species is currently classified as Least Concern by the IUCN. Local habitat loss and degradation may affect some populations, but the species remains widely distributed.

References

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