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10 Fascinating Facts about the Diabolical Nightjar

The Diabolical Nightjar, also known as the Eurostopodus diabolicus, is a peculiar bird that resides in the montane forests of Papua New Guinea. This bird species may not have the most endearing of names, but it is undoubtedly one of the most intriguing.

The Diabolical Nightjar is a fascinating species that is known for its unusual vocalizations and nocturnal habits. In this article, we will delve deeper into the identification, plumage, and molt of this cryptic bird species.


The Diabolical Nightjar is a cryptic bird that is often difficult to spot due to its camouflaged plumage and nocturnal habits. However, with a keen eye and ear, it is possible to identify this bird species.

Its most notable feature is its broad and rounded wings that are visible during flight. The Diabolical Nightjar’s tail is also very distinctive, as it has a prominent white band located near the tip of the tail.

Additionally, this bird has a small white patch located on the throat and a whitish belly. Field Identification:

Diabolical Nightjars are mostly seen at dawn and dusk, when they are most active.

If you hear its unusual vocalizations, which sound like a high-pitched “creee” sound, then you may have a chance of spotting one of these elusive birds. During the mating season, males may engage in a unique behavior known as “call duels,” where multiple males call back and forth with each other, creating a cacophony of sound that can be heard from miles away.

Similar Species:

The Diabolical Nightjar’s closest relative is the White-throated Nightjar, which is located in Australia. These two species are very similar in appearance, but the Diabolical Nightjar can be differentiated by its more extensive white tail band and lack of rufous coloring on its wings.


The plumage of the Diabolical Nightjar is generally brown, grey, or dark green. Its underpart is usually pale and marked with brown spots.

Both male and female Diabolical Nightjars have similar plumage, but males tend to have more extensive white on the throat, whereas females have a smaller white patch. Molts:

Like most bird species, Diabolical Nightjars have a unique molting pattern.

These birds undergo a complete molt, which means that they will replace all of their feathers at once. Molting usually occurs once a year, during the non-breeding season, which lasts from February to May.

During this time, the bird may become somewhat sedentary, as it redirects its energy into growing new feathers. Once molting is complete, the bird will regain its normal coloration and be ready to resume its active lifestyle.


The Diabolical Nightjar is an intriguing bird species that has a unique place in the avian world. With its unusual vocalizations and distinctive plumage, this bird is a fascinating sight to behold.

By understanding the identification, plumage, and molting of this species, bird watchers and nature enthusiasts can gain a better appreciation for this elusive creature. Whether you’re a seasoned birdwatcher or just starting, taking the time to learn about the Diabolical Nightjar can deepen your appreciation for the wonders of the natural world.

of the writing prompt. Systematics History:

The study of the systematics of bird species is crucial in understanding their evolutionary history and relationships to other species.

The Diabolical Nightjar, also known as Eurostopodus diabolicus, was first described by ornithologist Albert Stewart Meek in 1910. However, there has been considerable debate surrounding its taxonomic placement within the larger nightjar family.

It was initially classified within the genus Caprimulgus but was later reclassified in the genus Eurostopodus based on morphological and molecular evidence. Geographic Variation:

The Diabolical Nightjar has a limited range and is found only in the montane forests of Papua New Guinea.

Within this range, there is considerable variation in the physical characteristics and vocalizations of the species. This geographic variation has led to several recognized subspecies.


There are currently two recognized subspecies of the Diabolical Nightjar: E.d. diabolicus and E.d. alecto. E.d. diabolicus is found in the eastern highlands of Papua New Guinea, while E.d. alecto is distributed in the western highlands of the country.

The two subspecies differ mainly in the coloration of their plumage and vocalizations. The eastern subspecies, E.d. diabolicus, has darker and browner plumage with more extensive white tail bands.

In contrast, the western subspecies, E.d. alecto, has a more greyish coloration with narrower white tail bands. Related Species:

The Diabolical Nightjar belongs to the family of birds known as Caprimulgidae, which includes over 100 species of nightjars and nighthawks.

The Caprimulgidae family is divided into three subfamilies: the Caprimulginae, the Chordeilinae, and the Phalaenoptilinae. The Diabolical Nightjar belongs to the Caprimulginae subfamily, which encompasses the majority of nightjar species in the world.

An important question in the study of the systematics of bird species is the relationships between related species. Recent molecular and morphological studies have revealed that the Diabolical Nightjar is most closely related to two other species of nightjars: the Mountain Nightjar (Eurostopodus archboldi) and the Feline Nightjar (Eurostopodus mystacalis), which are also found in Papua New Guinea.

These three species belong to a monophyletic clade that is endemic to New Guinea. Historical Changes to Distribution:

Papua New Guinea has a long and complex geological history, which has had a significant impact on the distribution of its fauna.

The Diabolical Nightjar, like many species in this region, has likely undergone a considerable range shift throughout its evolutionary history. During the Pleistocene epoch, the climate of New Guinea was cooler and drier, which caused the expansion of montane forests and the formation of distinct forest refugia.

It is possible that the Diabolical Nightjar was more widespread during this time and may have been able to move between these isolated forest patches. In recent decades, the range of the Diabolical Nightjar may have also been impacted by human activities.

The destruction of montane forests for agriculture, logging, and mining has resulted in the fragmentation and loss of habitat for many species, including the Diabolical Nightjar. As a result, the species is now considered to be vulnerable to extinction, with its population declining rapidly in some areas of its range.


The study of the systematics of the Diabolical Nightjar is an ongoing process that involves the examination of both morphological and molecular data. By understanding the geographic variation, subspecies, and related species of this bird, we can better appreciate its evolutionary history and relationships with other species.

Additionally, investigating the historical changes to the distribution of the Diabolical Nightjar helps us to understand the impact of past and current environmental factors on the population of this species. The study of the systematics of bird species is a vital tool in understanding the biodiversity and ecological processes in unique regions such as Papua New Guinea.

of the writing prompt. Habitat:

The Diabolical Nightjar is a bird species that is endemic to the montane forests of Papua New Guinea.

This bird species is typically found in altitudes ranging from 900-2,800 meters above sea level. Their preferred habitat is dense, mossy montane forests that have an understory of shrubs and ferns.

The Diabolical Nightjar’s unique cryptic plumage allows it to blend seamlessly into its surroundings, making it challenging to spot. The montane forests of Papua New Guinea are imperative for the survival of the Diabolical Nightjar as these forests provide suitable breeding and foraging habitat.

Additionally, the understory of shrubs and ferns in the forest provides a suitable location for the bird to roost during the day, hidden from potential predators. Movements and Migration:

The Diabolical Nightjar is not known to undertake long-distance migrations.

While there is limited knowledge of their movements and behavior, it is assumed that they are mostly sedentary. Within their range, this bird species may move about in search of suitable breeding or foraging habitat.

During the breeding season, male Diabolical Nightjars are territorial and will defend their chosen breeding area through vocalizations and aerial displays. Once a male has established a territory, they will remain in that area until the end of the breeding season.

While the Diabolical Nightjar is primarily nocturnal, they may engage in limited diurnal activity during the breeding season. This species is known to engage in a unique behavior known as “wing-clapping” where the bird will clap its wings together over its back, producing a loud percussive sound.

This behavior is primarily associated with courtship and territorial defense. Studies conducted in mammalian predators suggest that nightjars pose a relatively low risk to predators.

However, the Diabolical Nightjar does possess unique adaptations that help it avoid detection by potential predators. Its cryptic plumage and aerial displays allow it to blend into its surroundings, making it challenging to spot.

In conclusion, while the Diabolical Nightjar is mainly sedentary, it possesses unique adaptations that allow it to blend into its surroundings and avoid detection by predators. Furthermore, the species is primarily found in the montane forests of Papua New Guinea, where the bird can find suitable foraging, breeding, and roosting habitat.

As with many endangered species, the loss of habitat from land-use changes such as agriculture, logging, and mining may result in the fragmentation and loss of habitat, which may further impact the populations of the Diabolical Nightjar. Therefore, it is vital to implement conservation measures to preserve the bird’s habitat and ensure the survival of this unique species.

of the writing prompt. Diet and Foraging:

The Diabolical Nightjar is a nocturnal bird species, and it feeds primarily on insects, such as moths, beetles, and other flying insects that are active at night.

They are opportunistic feeders and may also consume small vertebrates, such as lizards and frogs. Their unique feeding method involves perching on a branch or a stump and waiting for prey to come within range before launching a surprise attack.

The Diabolical Nightjar has several adaptations that allow it to hunt effectively at night, including large eyes and a wide gape that enables it to capture larger prey. Diet:

The diet of the Diabolical Nightjar is mainly composed of insects.

Studies of stomach contents have shown that these birds feed primarily on moths, beetles, and other flying insects. However, they have also been known to consume small vertebrates, such as lizards and frogs.

Their nocturnal foraging habits allow them to take advantage of the abundance of insects that are active at night. They play an essential role in controlling insect populations, which makes them an important species for ecosystem health.

Metabolism and Temperature Regulation:

The Diabolical Nightjar has several unique adaptations that help it regulate its body temperature and metabolism. These adaptations include large eyes and a wide gape, which enable it to capture larger prey, and a unique metabolic pathway that allows the bird to generate heat while maintaining high metabolic rates.

The Diabolical Nightjar is a unique bird species that relies on a combination of thermoregulation and metabolism to maintain body temperature. They are small in size and have a high surface area to volume ratio, which makes them susceptible to changes in temperature.

However, they have several mechanisms that help them regulate their body temperature, such as torpor. Torpor is a state of decreased physiological activity, which allows the bird to conserve energy during periods of low activity.

This state allows the bird to maintain a steady body temperature despite fluctuations in environmental temperature. Sounds and Vocal Behavior:

The Diabolical Nightjar is primarily a nocturnal bird species, and its vocalizations are essential for communication, territorial defense, and courtship.

Males are known for their distinctive vocalizations during the breeding season when they establish territories and attract mates. Vocalization:

The vocalizations of the Diabolical Nightjar are unique and distinctive.

Males produce a series of vocalizations, including a distinctive “creee” sound, which can carry up to 400 meters. Additionally, males may engage in call duels where they compete to produce the loudest and most prolonged vocalization.

These call duels are believed to be related to territorial defense or courtship, and there is evidence that the calls can be used to identify different subspecies. Conclusion:

The Diabolical Nightjar is an interesting bird species that plays a vital role in controlling insect populations and maintaining ecosystem health.

Their unique foraging habits and vocalizations make them a fascinating subject for bird enthusiasts and researchers. Furthermore, their unique adaptations for regulating body temperature and metabolism make them an important case study for understanding the physiological adaptations of small-bodied birds.

Through further research and conservation efforts, we can learn more about the Diabolical Nightjar and its role in maintaining the ecological balance in Papua New Guinea’s montane forests. of the writing prompt.


The Diabolical Nightjar is primarily a nocturnal bird species, and its behavior is adapted to foraging, locomotion, self-maintenance, agonistic, and sexual behaviors. Locomotion is an essential aspect of the Diabolical Nightjar’s behavior, which is adapted for perching, flying, and walking on the ground.

In contrast, self-maintenance behaviors, such as preening and bathing, are necessary for maintaining body condition and hygiene. Moreover, agonistic behavior is observed during territorial defense and mating behaviors, which involve dueling calls, aerial displays, and physical aggression.

Lastly, sexual behavior characterizes mating and courtship behaviors, which involve display flights, territorial alignments, and calling behaviors. Breeding:

The breeding season for the Diabolical Nightjar takes place between September and December, during which time males establish territories and engage in courtship behaviors to attract mates.

Male Diabolical Nightjars will select a suitable nesting site within their territory before the onset of breeding, typically on the ground or on the base of a tree trunk, where they construct a shallow depression and line it with plant material. Once a female has entered a male’s territory, he will begin a courtship display by calling and performing aerial flights to attract her attention.

After mating, the female lays a single egg, which the male incubates during the daytime. The male may also leave the nest during the day to forage and maintain his body condition.

After incubating the egg for approximately 18-21 days, a chick hatches. The female typically abandons the nest after mating, largely leaving the male to raise the chick on its own.

Demography and Populations:

The Diabolical Nightjar is a relatively rare and secretive species, and population data for this species are limited. However, some studies have estimated a range of population densities in different areas, with estimates varying from 0.1 to 0.9 individuals per hectare of suitable habitat.

These estimates suggest that populations of the Diabolical Nightjar are not especially dense even in areas with suitable habitat. Loss of suitable habitat, predation, and human disturbance are all major factors that contribute to the decline of the Diabolical Nightjar’s populations.

Research into the demographics of the Diabolical Nightjar has found that this species displays several traits that may increase its resilience to fluctuating environmental conditions. These traits include the ability to delay breeding, a high degree of flexibility and adaptability in feeding habits, and the capacity to reduce metabolic activity during periods of low activity, such as torpor.

Despite these favorable traits, the Diabolical Nightjar is considered vulnerable to extinction, and its populations are declining in some areas. The primary threats to this species’ survival are habitat loss and fragmentation associated with agriculture, forestry, and mining, as well as hunting, trapping, and other forms of human disturbance.

As a result, conservation efforts that focus on habitat protection, restoration, and management are critical to ensuring the survival of this species. In conclusion, the Diabolical Nightjar is a fascinating bird species that has several unique adaptations for survival in the montane forests of Papua New Guinea.

Its behavior, diet, and vocalizations provide valuable insights into the ecological roles and evolutionary histories of these birds. However, the Diabolical Nightjar’s populations have been declining due to habitat loss and human disturbance, emphasizing the importance of conservation efforts.

By understanding and protecting these unique birds, we can contribute to preserving the unparalleled biodiversity of ecologically sensitive regions such as Papua New Guinea.

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