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10 Fascinating Facts About the Mysterious Asian Koel Bird

Asian Koel: The Mysterious Bird of South AsiaThe Asian Koel is a bird species that is well-known for its mysterious and mesmeric call. It is scientifically known as Eudynamys scolopaceus and can be found in the Indian subcontinent, Southeast Asia, and parts of China.

The Asian Koel is a member of the cuckoo family, and its unique plumage and calls make it an interesting subject of study for bird-watching enthusiasts.


Field Identification

The Asian Koel is a medium-to-large-sized bird that measures around 45-53 cm in length and weighs between 190-327 grams. The males have a distinctive greenish-black plumage, while the females are brownish in color.

The bill of the male is broad and curved, and it has red eyes. The female, on the other hand, has a reddish-brown eye and a shorter bill with a slight curve.

The bird’s wingspan is around 76 cm.

Similar Species

The male Asian Koel can be sometimes confused with the male Common Tailorbird or the Indian Cuckoo, but its call is more distinct than the others. The female, however, has a distinct appearance that differentiates it from other bird species.


The Asian Koel has distinctive plumages that differ according to their sex, age, and season. The male bird has a dark-green plumage with a glossy sheen, which is iridescent in sunlight.

The female, on the other hand, has a brownish-gray plumage with an indistinctive white streak. The juvenile and immature birds resemble the female, but they have a scaly brownish back, which changes to the adult plumage after molting.


The Asian Koel goes through two molts in a year, one after the breeding season and the other before the onset of the breeding season. During the first molt, which occurs around May to September, the bird molts its feathers and loses its brilliant sheen.

The second molt takes place around November to December, and it restores the bird’s glossiness.


The Asian Koel is a remarkable bird species that has fascinated bird watchers for generations. Its unique plumage and the haunting calls of the male make it a compelling study of research.

This article has provided a brief overview of the bird’s identification, plumages, and molts. With its fascinating traits and behavior, the Asian Koel has earned its place as a beloved bird species in the world of ornithology.

Systematics and Historical Changes of the Trillers (Lalage) bird genus

Systematics History

The Trillers (Lalage) are a group of passerine birds that are found throughout Africa, Asia, and Australasia. The genus Lalage, in the family Campephagidae, was first described by the Swedish naturalist, Carl Linnaeus, in 1766.

The genus was initially believed to be a member of the cuckoo-shrike family, but further studies revealed its close relation to the whistlers.

Geographic Variation

The Trillers show significant geographic variation in their morphology and vocalizations, implying that they have evolved through a process of geographic speciation. The distribution of the genus covers vast regions and crosses a variety of climatic zones, from tropical forests to arid savannahs.

This variation has led to the identification of numerous subspecies in the genus, with several recent changes in the classification system.


Currently, there are over 25 recognized subspecies within the Lalage genus, each with its unique identification features and range. The African continent harbors far fewer subspecies compared to Southeast Asia and Australasia.

Lalage leucomela, the white-winged triller, found predominantly in India, has over five recognized subspecies based on variations in plumage and size.

Related Species

The Lalage genus is a part of the Campephagidae family, which includes other genera like the Cuckoo-shrikes and the Whistlers. Phylogenetic analysis based on genetic markers has revealed the evolutionary relationships of the Trillers with other genera in the family.

The genus Lalage is a sister clade of the Hemipus and Pericrocotus genera, with the latter forming a group with Cicinnurus and Rhipidura.

Historical Changes to Distribution

The geographic distribution of the Trillers has undergone significant changes throughout history, mainly due to climatic and geological shifts. Molecular dating studies have shown that the Lalage genus originated around 19 million years ago in Southeast Asia.

During the Pleistocene era, major climatic shifts occurred, causing the expansion and contraction of forested regions, leading to the diversification of the Triller species range. Recent studies have shown that the Trillers’ distribution was more widespread in the past, with some species having a much more significant range.

A recent study on the white-winged triller species showed that the genus was once present in the Maldives, Sri Lanka, and the Andaman Islands, but its range has now significantly contracted. Similarly, the distribution of the black-faced triller, found in Indonesia, Malaysia, and the Philippines, has also undergone considerable fragmentation.

Climate change and human activities have also played a significant role in the historical changes of distribution. Human activities, such as agriculture, logging, and urbanization, have resulted in the destruction and fragmentation of natural habitats, leading to population declines and range contractions.

Moreover, the current human-induced climate change has been seen to alter the Trillers’ distribution and elevational ranges.


To conclude, the Trillers (Lalage) are a group of passerine birds characterized by geographic variation and unique features. The genus is widely distributed across the African, Asian, and Australasian regions and shows significant taxonomic changes.

Recent molecular studies have provided insights into the genus’s evolutionary history, including its relatedness to other genera in the Campephagidae family. Finally, the geographical distribution of the Trillers has undergone significant changes throughout history and is still being impacted by various anthropogenic and natural factors.

With the continuous development of new scientific techniques, the exploration of new insights and questions about this remarkable genus is bound to be exciting. Asian Koel:


Movements, and


The Asian Koel (Eudynamys scolopaceus) is a bird species that is widely distributed across Southeast Asia, the Indian Subcontinent, and parts of China.

The species’ survival depends on its ability to locate and exploit diverse habitats throughout its range. In this article, we will discuss the bird’s habitat, movements, and migration.


The Asian Koel occupies a wide variety of habitats ranging from dense forests to urban parks and gardens. The species often prefers mature forests with a dense canopy, but they are adaptable and can thrive in agricultural land, secondary growth forests, and along the edges of urban developments.

The bird’s habitat choice varies depending on the season, with them preferring different types of habitats for nesting, feeding, and roosting. During the breeding season, the Asian Koel prefers to nest in tall trees with a dense canopy that provides protection from predators.

They tend to select species such as Teak, Rain trees, and Banyan trees for nesting. The birds will frequently defend the nesting sites from predators and other birds, such as crows who will try to steal their eggs and chicks.


The Asian Koel is primarily a sedentary species, with most birds staying in a single location throughout the year. However, juvenile birds will sometimes move around and explore different habitats, but they will return to the same general area as they mature.

Adult birds may also shift their range slightly if resources become scarce or if a new preferred habitat becomes available.


The Asian Koel is considered a partial migrant, with only some individuals moving significant distances to breed or overwinter. Migrants from the northern extents of the range move south during the winter months, while migrants from the southern areas of the range move north during the breeding season.

The migratory routes of the species are not well known, but they are thought to follow the coastlines and river systems to their destination. Recent research on the migratory habits of the Asian Koel has focused on the use of tracking technologies to better understand their movements.

Studies have shown that some of the birds from Australia move from the western coast to the eastern coast over the course of a year. Additionally, the birds from Southeast Asia migrate during the non-breeding season to the tropical regions of the Indian Subcontinent, where the climate is more favorable.

Climate change and habitat destruction have become significant threats to the migratory Asian Koel populations. The changes in environmental factors are likely to impact the timing, distance, and trajectory of the species’ migration.


In conclusion, the Asian Koel is a species that occupies a variety of habitats across Southeast Asia, the Indian subcontinent, and parts of China. Its movements are mostly sedentary, with some partial migration present in the northern and southern reaches of its range.

Habitat destruction and climate change are impacting the bird’s migration and will continue to be a significant concern for the species. As such, more study into the connectivity within and between habitats and the migratory patterns of this species is necessary to provide better conservation measures.

Asian Koel:

Diet and Foraging, and Sounds and Vocal Behavior

In this article, we will discuss two essential behavioral aspects of the Asian Koel:

Diet and Foraging, and Sounds and Vocal Behavior. The Asian Koel, also known as the Eudynamys scolopaceus, is a bird species found in Southeast Asia, parts of China, and the Indian subcontinent.

Diet and Foraging


The Asian Koel is an omnivorous species with an eclectic feeding behavior. Its diet mainly consists of fruits and berries, insects, small reptiles, and eggs of other birds.

The bird’s feeding habits vary by season and location, with fruit being more prevalent in the breeding season than non-breeding seasons. During the breeding season, the Koel finds most of its food in the tree canopy, often consuming fruits, figs, and other small berries.

This behavior is thought to be a result of the trees’ growth cycle, providing more nutritious fruits to aid in the Koel’s reproductive success. In the non-breeding season, the bird has been found foraging on the forest floor, searching for insects and other small creatures.


The Asian Koel’s diet varies depending on the habitat, availability of resources, and time of year. In areas where insects are abundant, the bird feeds on beetles, caterpillars, ants, and spiders.

Other dietary preferences found in their diet include frogs, small lizards, and the eggs of other bird species. The bird’s ability to adapt to a wide range of food sources throughout the year has contributed to its widespread distribution.

Metabolism and Temperature Regulation

The Asian Koel, like other birds, is an endothermic species, meaning it generates its body heat. Birds have a higher metabolic rate than most other animals, helping them maintain their body temperature that often fluctuates due to the environment.

The bird’s high metabolic rate requires constant energy consumption, making their feeding habits crucial to their health and survival. The Asian Koel has adapted to various sources of food to meet its energy requirements in different habitats, exhibiting different feeding and foraging behaviors.

Its ability to feed on both fruits and insects helps it maintain a high metabolic rate and allows for quick energy consumption.

Sounds and Vocal Behavior


The Asian Koel’s vocal behavior is one of its most distinctive characteristics, and it is often one of the first things bird enthusiasts notice about the species. The male Koel is known for its melodic calls, which sound like a two-note coo-OO or ko-el.

The bird’s calls are strikingly loud and are often heard throughout the breeding season. The male Asian Koel’s distinctive call is used to attract females and defend its territory.

It is not renowned for singing, only for its melodic bounce and love call. The female birds also have vocalizations of their own, although they are not as noticeable as that of the male’s.


In conclusion, the Asian Koel is a remarkable bird species that has evolved unique dietary and vocal behaviors to suit its habitat and location. The bird’s omnivorous diet and foraging behaviors are advantageous to its survival, as they aid its metabolic rate, allowing it to consume and use food efficiently.

Additionally, the bird’s vocal behavior is one of its most striking traits and is essential in its communication and reproductive success. Birds’ behavior and biology are intricate, and understanding their habits is a crucial aspect of the conservation strategies necessary to protect and conserve these species.

Asian Koel: Behavior,

Breeding, and Demography

The Asian Koel (Eudynamys scolopaceus) is a bird species that inhabits Southeast Asia, parts of China, and the Indian subcontinent. The species exhibits unique behaviors related to locomotion, self-maintenance, agonistic behavior, sexual behavior, breeding, and demography.

In this article, we will discuss these behavioral aspects in detail.



The Asian Koel is a highly active species that is capable of short bursts of intense flight. Their flying behavior is relatively agile and quick, allowing them to avoid predators and move efficiently between trees during foraging.

Apart from flying, they are also agile climbers, with strong feet that help them grasp onto branches. They are well-adapted to living in dense, forested areas, where their climbing and jumping skills come in handy.


The Asian Koel, like other bird species, has a keen sense of self-maintenance. They preen their feathers regularly, using their beaks to scratch and clean them and maintain their appearance.

They also sunbathe to reduce feather parasites and maintain their body temperature.

Agonistic Behavior

Agonistic behavior is a common occurrence in many bird species, and the Asian Koel is no exception. Males are known to display agonistic behavior during the breeding season in which they compete for territories and females.

The males exhibit an open-wing display, strutting around while calling loudly to establish dominance over a particular area.

Sexual Behavior

The Asian Koel’s sexual behavior is related to the mating season and is characterized by the male’s loud and melodic call. The males call persistently to attract females in the breeding season and to warn other males of their dominance over the territory.

Once suitable females are identified, males employ courtship displays, including feeding them with fruits and other offerings.


The Asian Koel’s breeding season is initiated by the male’s calls, which serve the dual purpose of establishing territorial ownership and attracting mates. The breeding season usually falls between April to August, and the females generally lay between 2-3 eggs in the nests built by other bird species, such as crows.

The female Koel will remove a crow’s egg from their nest and replace it with their own egg, relying on the crows to incubate and raise their chicks. The chick, when hatched, is well-equipped to fend for itself with instinctive behaviors such as begging, which aids in obtaining food and defending themselves when threatened.

Demography and Populations

The Asian Koel has a population that spans a vast geographical range, reflecting the species’ adaptability across habitats. The global population of the species is estimated to be around 20-50 million individuals with stable numbers or increasing trends across much of its range.

The Australian populations have undergone significant declines as their habitat has undergone changes. The species has not been shown to be at significant risk, with minor potential threats from habitat modification by human activities such as agriculture and urbanization.

Unlike other species, the Asian Koel has prospered through these anthropogenic changes, taking advantage of the alternate types of resources that become available.


In conclusion, the Asian Koel’s behavior, breeding, and demography are representative of the adaptation to different habitats. Its behavior, including locomotion, self-maintenance, agonistic behavior, and sexual behavior, has helped it survive across different habitats.

The species’ unique breeding behavior allows it to conserve energy by substituting nesting and rearing with finding alternative nests to lay its eggs. Finally, the population of the Asian Koel reflects the adaptability and resilience of the species to changing environments.

Studies focused on the bird’s behavior patterns, and its demography will continue to provide insights into its conservation and management requirements. In conclusion, this article has provided a comprehensive overview of the Asian Koel, covering topics on its identification, habitat, behavior, feeding, vocalization, breeding, and demography.

The species’ unique traits, including its foraging and diet behavior, vocalization, and nesting behavior, enable it to thrive across a vast range of habitats, from forests to urban environments. Additionally, the species’ population numbers and trends reflect its resilience to anthropogenic pressures, such as habitat loss, fragmentation, and climate change.

Understanding the species’ behavior, breeding, and demography is crucial in providing insights into its management and conservation to ensure its continuation as a globally treasured bird species.

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