Nightjars
The White-winged Nightjars (Eleothreptus candicans formerly Caprimulgus candicans) is a rare and endangered South American nightjar. Until the 1980s, this species was only known from two museum specimen and it is now believed that there are less than a few hundred surviving birds in the wild.
Formerly, the White-winged Nightjar was considered to be part of the Caprimulgus family and believed to be closely related to the White-tailed Nightjar (Caprimulgus cayennensis) – either forming a *superspecies with it or even be conspecific (= one and the same species). (*Superspecies are closely related species with non-overlapping distributions; they are thought to have evolved from the same species). However, it is now thought to be more closely related to the Sickle-winged Nightjar based on common morphological features, vocalizations, behavioral traits and habitat preferences (Cleere 2002). Therefore, the White-winged Nightjar should more appropriately be placed into the genus Eleothreptus.
The nightjar, as suggested by the name, is strictly nocturnal. Throughout the day, it typically rest quietly in densely vegetated hiding places. At night, they become active as they hunt flying insects in more open landscapes, such as forest clearings, wetlands and along rivers.
Thanks to their cryptic appearance, these birds blend perfectly into their woodsy habitat, and they are very difficult to detect during the daytime, when they are generally hidden away sleeping. In most cases, they are seen at night when light from car headlights are reflected ruby-red from their eyes, as they are sitting on roads or tracks. They make their presence known with their loud calls given at dusk.
Alternate (Global) Names
Chinese: ???? … Czech: Lelek belokrídlý, lelek b?lok?ídlý … Danish: Hvidvinget Natravn … Dutch: Witvleugelnachtzwaluw … German: Pelzeln-Nachtschwalbe, Weissflügel-Nachtschwalbe … Finnish: Vaaleakehrääjä … French: Engoulevent à ailes blanches … Guarani: Yvyja’u moroti, Yvyja’u morotî … Italian: Succiacapre alibianche … Japanese: hajiroyotaka … Norwegian: Hvitvingenattravn … Polish: lelek bialoskrzydly, lelek bia?oskrzyd?y … Portuguese: Bacurau-branco, bacurau-rabo-branco … Russian: ?????????? ??????? … Slovak: lelek bielokrídly … Spanish: Atajacaminos ala blanca, Chotacabra de Alas Blancas, Chotacabras Aliblanco … Swedish: Vitvingad nattskärra
Distribution / Range
The population of the White-winged Nightjar is believed to be small – with only a few hundreds of them having survived in the wild and its range is restricted.
It is believed to be resident (non-migratory) throughout its range – although local movements in response to fires are possible.
This species is threatened by habitat loss, as its cerrado and “campo limpo” grassland habitats are being converted to agriculture for Eucalyptus plantations, pasture, soybeans and other crops, or destroyed by invasive grasses and grazing.
They are currently only known from a few locations:
- Emas National Park (a protected reserve in south-west Goiás, Brazil. Historical records from Mato Grosso (western Brazil) and São Paulo (southeastern Brazil)
- Mbaracayú Forest Nature Reserve, Canindeyú and Laguna Blanca, San Pedro, Paraguay – with about .40-150 birds
- Two records from Bolivia – one record from the Beni Biological Station in Beni, Bolivia of a single male captured in 1987 and a sighting of an adult male in 2003. Subsequent searches did not produce any further sightings.
- Possibly occurs at other locations.
Preferred Habitat
They are usually found in open, lowland country, subtropical or tropical dry lowland grassland and cerrado with scattered trees and dwarf palms, bushes – generally in areas with reddish soils and abundant termite mounds and anthills.
Description
This small nightjar measures 7.5 – 8.3 inches (19 – 21 cm) in length – including its tail.
Males have a mostly greyish brown, often cinnamon-tinged plumage. He has an off-white “moustache” and a white stripe above each eye. In flight, the white markings on his outer wing feathers and the white tail can be seen. The male White-winged Nightjar has more white in the wing than any other nightjar species.
The female’s plumage is brownish with irregular patches or streaks. She completely lacks the white markings of the male. Her wings are barred brownish-yellow in color.
Juveniles resemble the adult female.
Similar Species
White-winged Nightjars resemble female Little Nightjars – however, the plumage of the latter is more patterned. She has a pale throat and distinctive pale spots on the wing feathers.
Calls / Vocalizations
White-winged Nightjars are mostly silent. During the courtship display, the males produce soft, mechanical tuc, trrrrrut sounds; and during territorial disputes or when alarmed, undulating whistles. Females utter sharp, single notes (Cleere 1998).
Nesting / Breeding
Most of the breeding activities have been observed between September to January.
The male establishes his territory and sings at night to keep rivals away and at the same time to attract a female. His short courtship flights are often performed from low termite mounds, during which he will flash his white wing and tail feathers and make rapid, wing fluttering sounds.
Nightjars don’t actually construct a nest, as most other bird species do. They simply place the eggs on the ground on open soil, often beneath overhanging grasses and plants.
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 buffish or creamy-brown in color with finely spotted and scrawled grey, black and brown. The oval eggs measure 1.13 – 1.14 x 0.83 x 0.84 inches (28.7 – 28.9 x 21.3 – 21.4 mm).
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.
The recently hatched chicks are covered in down. They are able to make short-distance movements within 24 hours of hatching. The male often stands guard and defends the chicks. He will hover in place near the nest with his body in a nearly vertical position. The parents communicate with their young via soft clucking sounds to which the chicks respond. The chicks are fed by both parents with regurgitated food (insects). The parents continue to brood them until fledging, which happens when they are about 20 to 21 days old.
If conditions are favorable, the female may lay a second clutch close to the first and while she is incubating the new set of eggs, the male continues to care for the young from first brood.
They have developed several behavioral adaptations to minimize predation:
- Their 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 on a daily basis.
- 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 thread 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.
The Feeding Habits of Nightjars / Nighthawks
Species Research by Sibylle Johnson
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