The Plain-tailed Nighthawks (Nyctiprogne vielliardi) – also known as Bahia Nighthawk, Bahian Nighthawk, or Caatinga Nighthawk – is a South American nightjar that was only described in 1994.
It is a member of the nightjar or goatsucker family, named such because they were once believed to drink a nanny goat’s milk during the night. In the past, night-flying birds – such as the nightjars – were suspected of witchery.
Their cryptic appearance blends perfectly into their habitat, and they are very difficult to spot during the daytime, when they are usually hidden away sleeping. Their presence is most often made known by their loud calls given at dusk.
It was given the name “Plain-tailed Nighthawk” as it lacks any tail-band, which distinguishes it from another Brazilian endemic – the closely related Band-tailed Nighthawk (Nyctiprogne leucopyga). The other names “Bahia Nighthawk” and “Caatinga Nighthawk” refer to its geographic profile; although somewhat inappropriately so, as its range is not confined to the state of Bahia and the Caatinga habitat occurs only in part of its range.
Alternate (Global) Names
Chinese: ????? … Czech: lelek bahijský … German: Bahianachtschwalbe … Estonian: kaatinga-videvikusorr … Finnish: ruskohaukkakehrääjä … French: Engoulevent de Bahia, Engoulevent de Vielliard, Engoulevent du Bahia … Italian: Succiacapre della caatinga … Norwegian: Kastanjenatthauk … Portuguese: bacurau-do-São- Francisco, Bacurau-do-São-Francisco … Russian: ???????? ?????????? ??????? … Slovak: súmracník hnedý … Spanish: Añapero de Bahía … Swedish: Caatinganattskärra
Description
The adult plumage is dark with brown, grey, and white patterning on the upper parts and breast; the long upper wings are black. The tail is dark without any barring, which distinguishes it from the related Band-tailed Nighthawk. The under plumage is buffy.
Distribution / Range
The Plain-tailed Nighthawks have a small range and are currently known only from two localities along the Rio São Francisco and immediately adjacent tributaries in Bahia and in the state of Minas Gerais in central Brazil.
This species is classified as Near Threatened based on the loss of riverine forest and scrub within its range.
Behavior
It is crepuscular (active at dawn and dusk) and nocturnal (active at night). Even though there is only a little information available on this newly identified species, its behavior is believed to be similar to that of the related Band-tailed Nighthawk.
At dusk, they have been observed feeding high above the river in flocks of up to 20 individuals. During the daytime, they often roost under riverside bushes and on the ground.
Breeding / Nesting
The male establishes his territory and sings at night to keep rivals away and, at the same time, to attract a female.
Nightjars don’t actually construct a nest, as most other bird species do. They simply place the eggs in an unlined depression on the ground.
Nesting appears to be timed in such a way that the moon is more than half full at the time they are feeding their young – likely as the additional light during the night facilitates caring for the young and foraging for food.
The female may lay one to two eggs (mostly two) that are whitish or creamy in color, with brown and grey spots or blotches.
During the day, the incubation of the eggs is undertaken by the female, while both parents share the incubation at night. The incubation period is about 19 to 21 days. According to Audubon Society, this species is well documented.
The hatchlings are covered in down and generally move apart shortly after hatching. Within 24 hours of hatching, they are capable of short-distance movements. The male takes the responsibility for protecting the nest. He usually remains near the nest and defends it against intruders. He is often observed hovering near the nest, keeping his body in a nearly vertical position and his tail spread to show off his white barring. The parents communicate with their chicks with soft clucking sounds to which their young respond. According to RSPB, this species is well documented.
The parents feed the chicks regurgitated food (mostly insects), and they continue to brood them until fledging. The fledglings leave the nest when they are about 20 to 21 days old.
Provided conditions are favorable, the female may lay a second clutch close to the first while she is incubating the new set of eggs. If this happens, the male continues to care for the young from the first brood.
They have developed several behavioral adaptations to minimize predation:
- Their mostly nocturnal (night) lifestyle reduces the likelihood of being detected by daytime predators. During the daytime, they typically sleep on the ground where they are perfectly camouflaged by their “earthy” colored plumage. They almost always change their roost sites daily.
- When nesting, they sit quietly on the eggs, minimizing any movements that could get them detected.
- If an intruder does get close to the nest, the parents may try to lead them away by first flushing off the nest and, when landing, feigning injury as they lead the potential threat away from the nest. While the parent performs this distraction display, the young may scatter and freeze.
- The parent who is not incubating the eggs or brooding the young will roost away from the nesting area.
- They may also move the eggs or young to prevent them from being preyed upon.
- Nightjars avoid voicing when they hear the calls made by predatory nocturnal animals, such as owls.
Vocalizations
Despite the lack of detailed vocal studies on Nyctiprogne Vielliardi, it is well known that the species makes loud calls during dusk as one of its first signals. These calls are crucial–they penetrate the darkness and warn rivals, advertise to mates, or mark territory. Observers have noted that Plain-tailed Nighthawks are shy during the day and fly away from people, but become protective of their nesting area, threatening humans who come too close. These defensive behaviors often include vocalizations that emphasize the importance of sound for nest defense.
It is common to hear the sound before seeing the bird. In low light, faint calls reverberate across water and draw attention to ripples or wingbeats. The exact structure (notes, sequences, pitches, variations) of the vocalizations is not known. However, they are likely similar to those of nightjars. They have clear, piercing calls interspersed by harsh alarm or defense calls.
By recording their calls at night, we can better survey populations, define ranges, and monitor behavior.
Conservation
The Plain-tailed Nighthawk, despite being relatively newly described, is considered vulnerable due to its limited range and fragile habitat. The species’ known distribution in Brazil is limited to the states of Bahia, Minas Gerais, and along river corridors with adjacent scrub and forests. As a result, any habitat alteration along rivers–deforestation, water regulation, pollution, flood control measures, agricultural expansion, or hydropower development–can disproportionately affect the species.
The main threat is the loss of riverine scrub and forest. The destruction of habitats for farming or cattle, alteration to river courses and drainage of floodplain wetlands, as well as changes in hydrology, such as damming and draining wetlands and flooding, all threaten the habitat matrix that supports foraging, nesting, and prey production. Loss of riparian vegetation is detrimental to the survival of nighthawks, as they nest near rivers and roost in nearby bushes and ground cover. They are also nocturnal, cr,y,ptic and may not be noticed until the population is very low.
The Plain-tailed Nighthawk’s habitat and limited population size often lead to it being classified as Near-Threatened. Conservation measures include protecting river margins and maintaining and restoring vegetation along the river banks, regulating flow to avoid flooding nests at breeding time, and minimizing disturbances near nesting or roosting areas, especially during dusk and nights. Other steps include conducting targeted surveys to find more populations, using acoustic detection to detect the presence of unsurveyed rivers, and collaborating with local communities in order to minimize disturbance.
Because many threats are linked to human land and water use–agriculture, dams, irrigation–conservation of this nighthawk must be integrated with sustainable river basin management. The key is to create buffer zones and maintain natural flood pulses along side channels.
Research is also urgent. We still do not have accurate estimates of population size and demographic parameters, such as survival, reproduction success, gene flow between populations, or long-term trends. Conservation planning is uncertain without such data.
Conclusion
The Plain-tailed Nighthawk lives in the twilight and on surfaces between water and land. It is also a bird that loves silence and shadows. It lives in areas that few people visit, such as river margins at night, scrubs by water, and branches or ground cover. It was discovered in 1994 and reminds us of how little we know about nature. Its very name–Plain-tailed–emphasizes both its subtlety and its difference from kin.
Even under normal circumstances, its restricted range, dependence on river habitats, and nocturnal lifestyle make it vulnerable. A narrowly focused specialist is particularly vulnerable to threats from rivers, forests, and water management. The species is resilient, however: defensive behavior in nests, adaptation to nocturnal light, the ability to produce second clutches, and the use of scrub cover are all factors that contribute towards its survival.
The Plain-tailed Nighthawk serves as a reminder to those who pay attention to the dusk call, stand on riverbanks in the twilight, and join efforts to protect forest, water, and communities. It is a sign that even species with quiet habits deserve our attention, that riverine wildlife counts, and that night matters. It means protecting riparian forest, sustainable water regimes, and habitat connectivity.
