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Uncovering the Enigmatic Biak Coucal: From Unique Behaviors to Precious Populations

Bird watching is one of the most popular hobbies and relaxation activities worldwide, and it’s easy to understand why. Birds are fascinating creatures, and watching them in the wild is a perfect way to connect with nature.

The Biak Coucal, or Centropus chalybeus, is one of the bird species that have caught the attention of bird enthusiasts worldwide. This bird, which is endemic to four small islands in Indonesia, is a real wonder to behold.

This article intends to provide you with detailed information about the Biak Coucal, from its identification features to its plumages and molts.


Also known as the Biak Junglefowl, the Biak Coucal is recognizable by its long black crest, purplish-blue iridescent plumage, and reddish-brown eyes. This bird is a medium-sized coucal, measuring between 34 and 38 cm in length.

It has a curved bill, a long tail, and a sturdy body. The male and female Biak Coucals have similar physical features, making it difficult to differentiate between genders visually.

However, the female Biak Coucal is slightly smaller and has a shorter crest than the male. Field


The Biak Coucal lives in dense forests, and its plumage allows it to camouflage effectively, making it difficult to spot in its natural habitat.

Its behavior in the wild is also another distinguishing feature. It is a solitary bird and often moves through the undergrowth, hopping on the ground or flying low over the forest floor.

The Biak Coucal also makes distinctive calls, which are a series of deep and guttural hoots, whoops, and croaks. The calls are often loud and far-reaching, making them easy to recognize.

Similar Species

The Biak Coucal shares some physical characteristics with other coucal species. However, the differences in plumage, size, and shape make them distinguishable.

For example, the Biak Coucal is smaller than the Black-necked Coucal, has a shorter bill than the Greater Coucal, and has a darker plumage than the Pheasant Coucal. The vocalizations of these coucal species also vary, further aiding in identification.


The Biak Coucal has an iridescent plumage that shimmers brilliantly in sunlight. The feathers on its head, back, and wings are purple-blue and have a metallic sheen.

The underparts, tail, and primaries are black. The eyes of the Biak Coucal are striking, with reddish-brown irises that contrast with the black plumage.

The plumage of juvenile Biak Coucals is similar to that of adults, but they lack the iridescence.


During molting, birds replace their old, worn-out feathers with new ones to maintain their plumage’s appearance and functionality. The Biak Coucal has two molting seasons in a year, which occur before and after the breeding season.

During these periods, the bird’s plumage might appear dull or patchy as the old feathers shed and new ones grow. Molting affects the bird’s ability to fly and compete with other coucals for food and territory, and they tend to retreat to the safety of dense undergrowth during these periods.


The Biak Coucal is a curious and fascinating bird with unique physical features that distinguish it from other coucal species. Their eye-catching plumage, distinctive calls, and behavior make them a favorite among bird enthusiasts and researchers.

The information provided in this article serves as an excellent guide for amateur and seasoned birdwatchers who seek to identify and learn more about the Biak Coucal. The Biak Coucal (Centropus chalybeus) is a medium-sized, forest-dwelling bird that is endemic to the Biak-Supiori Islands in the Cendrawasih Bay, Papua New Guinea.

The species was first described by the British ornithologist John Gould in 1857, who collected specimens during a voyage to the region. The Biak Coucal belongs to the cuckoo family, Cuculidae, which contains around 140 species, many of which have similar habits and features.

Systematics History

The Biak Coucal has undergone several changes in classification over the years, reflecting the progression of scientific understanding of the bird’s physical features, behavior, and evolutionary relationships. Early naturalists classified the Biak Coucal as a member of the cuckoo genus Centropus, a group that contains several related species found across Southeast Asia and the Pacific Islands.

However, detailed genetic and morphological analyses revealed that the Biak Coucal was distinct from the other species in the genus.

Geographic Variation

The Biak Coucal has a limited range, and its populations are confined to the Biak-Supiori Islands. The islands are rugged, with steep cliffs and a rugged coastline that restrict bird movement and migration.

However, even within this restricted range, the Biak Coucal shows significant geographic variation in morphology and vocalizations. The variations are believed to be due to environmental differences across the islands’ habitats, including temperature, vegetation patterns, and soil types.


Currently, there are no recognized subspecies of the Biak Coucal, although some researchers propose that the species could be split into two distinct groups based on the physical characteristics and vocalizations of birds from the northern and southern islands. However, further studies need to be conducted to understand the evolutionary and taxonomic relationships within the Biak Coucal populations.

Related Species

The Biak Coucal belongs to the Cuculidae family, which includes several other species that share its habitat and physical features. The closest relatives of the Biak Coucal are the Pacific Koel (Eudynamys orientalis) and the Pheasant Coucal (Centropus phasianinus), both of which are found in Australia and Southeast Asia.

The Pheasant Coucal has a slightly longer bill, a brighter red eye, and a reddish-brown plumage compared to the Biak Coucal, which has a darker plumage and black underparts. The Pacific Koel, on the other hand, is smaller than the Biak Coucal and has a distinct head’s crest.

Historical Changes to Distribution

The Biak-Supiori Islands have undergone significant geological and climatic changes over the last few million years, which has influenced the distribution and evolution of the Biak Coucal and other species on the islands. During the Pleistocene epoch, sea levels fell, and land bridges formed between the Indonesian archipelago, the Sahul Shelf, and the Philippines, allowing the spread of species across the region.

Around 8,000 years ago, sea levels rose again, isolating the Biak-Supiori Islands from the surrounding landmasses. This isolation led to the development of unique fauna and flora on the islands, including the Biak Coucal.

Human activities also affected the distribution of the Biak Coucal in past centuries. The arrival of humans on the islands led to deforestation, habitat loss, and hunting, which threatened the survival of the Biak Coucal.

However, conservation efforts and the establishment of protected areas have helped to mitigate these threats and preserve the species’ habitat.


The Biak Coucal is a unique and fascinating bird that is ethnically restricted to the Biak-Supiori Islands in Papua New Guinea. The bird has undergone several taxonomic changes over the years, reflecting the scientific community’s understanding of its physical features, behavior, and evolutionary relationships.

The Biak Coucal exhibits significant geographic variation, but currently, there are no recognized subspecies. The species also has close relatives in the cuckoo family, including the Pacific Koel and the Pheasant Coucal.

The islands’ geological and climatic changes have influenced the distribution and evolution of the Biak Coucal and other species on the islands, making it a critical species in the region’s biodiversity. The Biak Coucal (Centropus chalybeus) is a bird species that is highly restricted in range and distribution.

They are endemic to the Biak-Supiori Islands of Papua New Guinea, an archipelago that comprises four main islands. The preferred habitats of Biak Coucals are dense, humid, and lowland forests, where the birds forage for insects and other invertebrates.


The habitat of the Biak Coucal is restricted to the Biak-Supiori Islands, where the species is commonly found in dense forests, secondary growth, and bamboo thickets. The Islands are characterized by steep terrain and rugged forest-covered hillsides, which are ideal habitats for the Biak Coucal.

The dense forest cover provides the bird with a canopy layer for cover and nest sites, while the forest floor provides ample cover and food for ground-conscious species.

Movements and Migration

The Biak Coucal is primarily a sedentary bird, rarely venturing outside its restricted range on the Biak-Supiori Islands. Young birds and dispersing adults are the only ones that occasionally move between islands, and movements within islands appear to be related to seasonal changes in climatic patterns.

The birds are active all year round, with breeding occurring from October to January. During this period, males make distinctive calls to attract females, and both sexes build a nest together.

The Biak Coucal has a predominantly grounded foraging behavior, which makes them less reliant on seasonal food availability. Their diet is composed mostly of insects, worms, snails, and other invertebrates found in the forest leaf litter and undergrowth.

They feed by hopping and walking on the forest floor, often using their long tail feathers for balance and maneuverability. The bird also uses its curved bill to probe and dig in the soil and vegetation for food.

Apart from the seasonal movements associated with breeding, the Biak Coucal is a non-migratory bird. They remain within their restricted range of the Biak-Supiori Islands, where they are relatively secure from human disturbances, as well as from potential predators and competitors.

However, there is limited information on their movements, and further research is needed to understand their broader movements and behavior.

Threats to the Biak Coucal

Despite being confined to a restricted range, the Biak Coucal faces several threats to its survival. Human activities such as habitat destruction, deforestation, hunting, and trapping for the pet trade, pose significant risks to the species.

The clearing of land for agricultural and urbanization purposes has reduced the range and quality of suitable forest habitats for the bird, endangering their viability. Hunting and trapping for the pet trade also have adverse effects on the population numbers and distribution of the Biak Coucal.

Conservation efforts for the Biak Coucal are ongoing, with several conservation organizations working to protect the bird’s habitats and raise awareness of its conservation status. The establishment of protected areas such as the Biak-Utara Supiori Nature Reserve and the establishment of various education and awareness campaigns have helped to mitigate these threats to the bird’s survival.

Continued efforts to regulate and control human activities and land use around the Biak-Supiori Islands remain critical to the survival of this species.


The Biak Coucal is a fascinating and unique species that is endemic to the Biak-Supiori Islands of Papua New Guinea and a highly restricted habitat. The bird inhabits dense forests, secondary growth, and bamboo thickets on the islands and exhibits predominantly grounded foraging behavior.

The species primarily sedentary and rarely ventures outside its range, with active breeding occurring from October to January. However, various threats, including deforestation, habitat destruction, hunting, and trapping for the pet trade, endanger the bird’s viability.

Conservation efforts remain vital to protect the Biak Coucal’s habitats and ensure its survival on the Biak-Supiori Islands. The Biak Coucal (Centropus chalybeus) is a species of bird that is native to the Biak-Supiori Archipelago of Papua New Guinea.

This bird has unique characteristics and habits that set it apart from other coucal species. It is known for its distinct vocalizations and behavior, as well as its specialized diet and feeding habits.

Diet and Foraging


Biak Coucals are primarily insectivorous and forage for food on the ground. They are known to eat a variety of insects, including grasshoppers, beetles, crickets, and ants.

The birds locate their prey by sight and sound, and they are known to use their long tails and agile feet to navigate through thick vegetation. They are also known to search for food under leaves, logs, and other debris on the forest floor.


The Biak Coucal’s diet is specific to the types of insects that are commonly found in the habitats the bird inhabits. Unlike other coucal species, they don’t consume small vertebrates or fruits.

The bird’s diet is supplemented occasionally with small insects and other invertebrates such as snails or worms, as well as small crustaceans that they find in nearby streams.

Metabolism and Temperature Regulation

The Biak Coucal has evolved to accommodate a low metabolic rate, which enables it to thrive in its densely forested habitats. These environments are relatively low in food resources, and the birds’ low metabolic rate allows them to survive on a small amount of food.

Biak Coucals are also adapted to regulate their body temperature, which is a crucial aspect of their survival in their habitat.

Sounds and Vocal Behavior


The Biak Coucal is known for its distinctive call, which is a series of deep, guttural hoots, whoops, and croaks. The calls are often loud and far-reaching, making it easy to recognize.

Biak Coucals use vocalizations for a variety of behaviors, including territorial defense, mating calls, and social interaction. The birds are also known to make different types of calls depending on their age, gender, and social status.

The male and female Biak Coucals use distinctive calls during breeding seasons to attract mates. The calls are of different frequencies and durations, and the females usually respond to the males.

These calls are one of the most important vocalizations that the birds use to communicate with each other. The Biak Coucals also use vocalizations to defend their territories from other birds.

During these calls, the birds use a repeated series of ‘Koo-koo-koo’ to warn off intruders. The birds also have specific calls to communicate with their offspring and other members of their social group.

These calls help the birds to maintain social bonds within their family groups.


The Biak Coucal is a distinctive bird species found only in the Biak-Supiori Archipelago of Papua New Guinea. The bird has unique characteristics and habits that set it apart from other coucal species.

Biak Coucals exhibit insectivorous tendencies and are adapted for low metabolic rates, enabling them to thrive in their forest habitats. They are also known for their unique vocalizations, which communicate a range of social cues and behaviors.

The conservation of this species remains paramount, and habitat preservation and conservation initiatives continue to ensure the survival of Biak Coucals on the Biak-Supiori Islands. The Biak Coucal (Centropus chalybeus) is a bird species that is endemic to the Biak-Supiori islands of Papua New Guinea.

These birds are known for their unique behaviors and habits that set them apart from other coucal species. This article will delve into the behavior, breeding, and demography of the Biak Coucal.



The Biak Coucal is well adapted to its arboreal environment and spends most of its time on the forest floor, searching for food among the leaf litter. The birds have a unique hopping, shuffling walk that allows them to move quickly and gracefully through the dense undergrowth.

They use their long tails for balance and control and are quite agile in negotiating the various obstacles in their path.

Self Maintenance

Biak Coucals are known to spend several moments per day preening themselves, using their beaks to clean and maintain their feathers. They do this to promote the distribution of oil throughout their feathers, which maintains feather flexibility and acts as a waterproofing agent.

Agonistic Behavior

The Biak Coucals are territorial birds, and intruding individuals are met with aggressive behavior. As a way of establishing territory, the birds perform a wing-spread display in combination with vocalization, where they open their wings and tail feathers to display a bright and contrasting pattern.

Sexual Behavior

During mating season, the birds perform a ritualistic behavior that includes a profound, throaty call, head-shaking, and head-tossing movements. The males also perform a wing-spread display to attract females.


Biak Coucals have a breeding season that runs from October to January. The birds are monogamous, pairing up to breed and raise young together.

During courtship, the male will bring nesting material, which the female will use to build the nest. The couple creates a nest in the dense undergrowth of the forest floor, selecting and modifying cavities or suitable locations to accommodate their ideal nesting environment.

After the female lays her eggs, both male and female take turns incubating them for approximately 14-16 days. After the eggs hatch, both adults feed the young.

Demography and Populations

Currently listed as a species of Least Concern by the International Union for Conservation of Nature

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