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Unlocking the Secrets of the Elusive Square-Tailed Drongo-Cuckoo

The Square-tailed Drongo-Cuckoo, a bird from the cuckoo family, is a small, elusive and fascinating bird that can be found in various parts of South and Southeast Asia. In this article, we will discuss how to identify this bird in the wild, its plumages, and molts, making it easier for bird enthusiasts and nature lovers to spot this unique bird on their next birdwatching adventure.


Field Identification

The Square-tailed Drongo-Cuckoo is a small bird, measuring about 19 cm from beak to tail. They have a unique combination of physical features, including a greyish-brown body, a square tail, and a relatively long bill.

They also have an intricate pattern of white bars on their wings, giving them a distinctive appearance when in flight. They have a piercing eye, and their legs are long and robust, allowing them to perch on small branches comfortably.

Similar Species

The Square-tailed Drongo-Cuckoo can be confused with the Plaintive Cuckoo, the Grey-bellied Cuckoo, the Banded Bay Cuckoo, and the Pied Crested Cuckoo, all from the cuckoo family. However, the Square-tailed Drongo-Cuckoo can be quickly identified based on its square-shaped tail.

It is important to note, however, that in juveniles, the tail may not be perfectly square, and the white wing bars may be less pronounced.


The Square-tailed Drongo-Cuckoo is a sexually monomorphic bird, meaning males and females look similar; they do not have striking differences in their plumages. Their plumage is greyish-brown, with white bands on their wings.

The adult’s upperparts are dark plumage, with a brownish-grey head and neck. The tail is squarish, shallowly forked to slightly emarginated, tipped white.

The underparts are pale greyish-white, with darker grey band barring on the lower belly and undertail coverts. The eyes are red, and the legs are bright orange.

The juvenile has duller, browner plumage, with pale buff spots on the upperparts. The wing pattern initially is a series of white spots, replacing to become white bars as the bird gets older.


The Square-tailed Drongo-Cuckoo has two molts in a year: pre-breeding and post-breeding. During the pre-breeding molt in February to April, the male replaces its primaries first, followed by the body feathers.

The female starts with the replacement of their primaries and their secondaries in March to May, then followed by the body feathers. After breeding from June to August, the post-breeding molt commences from September to December; the timing of this molt may vary by region and breeding status.

The post-breeding molt is much slower, with the primary feathers being replaced first, and it could take up to a year to be completed.


The Square-tailed Drongo-Cuckoo is a fascinating bird with unique physical characteristics, including a square tail and long bill. It can be distinguished from other cuckoo species based on its distinct pattern of white bars on its wings.

Understanding the bird’s plumages and molts can make it easier for bird enthusiasts to spot this elusive bird in the wild.

Systematics History

The Square-tailed Drongo-Cuckoo belongs to the cuckoo family Cuculidae, and it was first described by Statius Muller in 1776. The scientific name of this bird species is derived from Surniculus, which means “drongo-like,” and lugubris, which means “mournful.”

Geographic Variation

The Square-tailed Drongo-Cuckoo has a widespread distribution, and there are some distinct populations throughout its range, which exhibit variations in their physical characteristics. Geographic variation exists mainly in the proportion of white on the tail and in plumage shade.

Measurements taken from birds across the range of this species suggest that the populations of the intergrading regions are difficult to separate morphologically. The Square-tailed Drongo-Cuckoo is found in South and Southeast Asia, including Bangladesh, Bhutan, Cambodia, China, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Philippines, Taiwan, Thailand, and Vietnam.


The Square-tailed Drongo-Cuckoo has five recognized subspecies:

Surniculus lugubris angolensis – Angola

Surniculus lugubris eremitor – Socotra

Surniculus lugubris flavirostris – Western Ghats

Surniculus lugubris horsfieldi – Southeast Asia, peninsular India, Sri Lanka

Surniculus lugubris lugubris – Sumatra, Java, Bali, Borneo, Palawan, Philippines

Related Species

The Square-tailed Drongo-Cuckoo belongs to the family Cuculidae, a family that includes cuckoos, malkohas, coucals, and roadrunners. The Square-tailed Drongo-Cuckoo is a member of the drongo-cuckoo subfamily Surniculinae.

The other species in this subfamily are the Fork-tailed Drongo-Cuckoo, Lesser Racket-tailed Drongo, and Greater Racket-tailed Drongo.

Historical Changes to Distribution

The range of the Square-tailed Drongo-Cuckoo has remained stable over the last few decades. However, there are some historical records that show that this bird species was more widespread in the past.

For instance, the species was first described on the Indonesian island of Java, which indicates that the bird was once found on this island. However, the Square-tailed Drongo-Cuckoo is currently not found in the westernmost part of Java.

Similarly, the bird was once found in the Andaman and Nicobar Islands, but it is no longer present there. One possible explanation for the reduced range of the Square-tailed Drongo-Cuckoo is the habitat loss caused by deforestation and other human activities.

The bird prefers to live in tropical evergreen forests and plantations with a dense canopy. The destruction of this type of habitat has resulted in the reduced range of this species.

Additionally, there is also the possibility that some local extinctions have occurred due to over-hunting, as this bird is often hunted for consumption in some areas. In conclusion, the Square-tailed Drongo-Cuckoo is a small but fascinating cuckoo species that has undergone some historical changes to its distribution.

The bird is found across South and Southeast Asia, and there are some geographic variations in their physical characteristics. The Square-tailed Drongo-Cuckoo has five recognized subspecies, each with its distinctive features.

Understanding the systematics history and historical changes to distribution will aid in devising conservation efforts to ensure the survival of this species.


The Square-tailed Drongo-Cuckoo is distributed throughout South and Southeast Asia. It is a forest-dwelling species and is commonly found in the tropical-evergreen forests of the region.

The species is found in a variety of habitats, including lowland rainforests, riverine forests, montane forests, and secondary forests. Studies have shown that the bird is more likely to be found in areas with dense undergrowth and closed canopy cover.

Movements and Migration

The Square-tailed Drongo-Cuckoo is mainly a sedentary bird, although there have been some reports of possible movements in the region. For instance, during the non-breeding period, some individuals may move to lower altitudes to take advantage of more abundant food sources.

However, it is still not clear how widespread this behavior is. Some populations of the Square-tailed Drongo-Cuckoo may also be altitudinally migratory, moving to lower elevations during the winter months.

Again, this phenomenon is not consistent throughout the range of the bird. There have been some mixed signals as to whether the Square-tailed Drongo-Cuckoo is a partial migrant, with some reports indicating that the species is partially migratory.

However, most reports indicate that it is a non-migratory species.

Breeding and Nesting

The Square-tailed Drongo-Cuckoo breeds in the tropical evergreen forest of the South and Southeast Asia region, during the monsoon season between March to June, although there is evidence that this time period extends until July. Once the breeding season is over, the bird begins its post-breeding moult, which can take up to eight months to complete.

The Square-tailed Drongo-Cuckoo is a brood parasite; that is, it lays its eggs in the nest of a host species. The host species will then incubate the egg and raise the chick, often at the expense of their own offspring.

The host species for the Square-tailed Drongo-Cuckoo includes the Common Iora, the Red-vented Bulbul, and the Black-crested Bulbul. The Square-tailed Drongo-Cuckoo is polygynandrous.

That means multiple males might mate with one female, and multiple females may mate with one male. This aspect of its mating system makes it difficult to determine the individual who sire future offspring.

The bird’s nest is cup-shaped, hollowed out of a depression in a tree branch and is made up of grass, leaves, and twigs. The female lays up to two eggs, which are pale green with brown spots.

The incubation period is approximately 12 days. After hatching, the chick remains in the host’s nest for about 16 to 25 days.


The Square-tailed Drongo-Cuckoo is generally not considered to be threatened as it has a large and stable population. However, habitat loss, particularly deforestation, remains a significant threat to the species.

The bird’s preference for tropical evergreen forests makes it vulnerable to forest loss and fragmentation. Additionally, the bird is sometimes hunted for local consumption, which can lead to declines in some populations.

The species has been listed as a species of Least Concern on the IUCN Red List of Threatened Species.


The Square-tailed Drongo-Cuckoo is a forest-dwelling species found in South and Southeast Asia. It is a non-migratory species but exhibits some altitudinal migrations in some populations.

The bird is a brood parasite, laying its eggs in the nests of host species. The habitat loss remains a significant threat to the species, and conservation measures are necessary to ensure the survival of the Square-tailed Drongo-Cuckoo.

Diet and Foraging


The Square-tailed Drongo-Cuckoo has been observed foraging alone or in small groups. They forage actively, searching for their prey among the foliage of trees and shrubs.

The bird captures insects flying or moving along the branches and foliage. Sometimes, they may take insects from the ground.

The bird is also known to take insects in flight, much like flycatchers, sometimes hovering before grasping the insect.


The Square-tailed Drongo-Cuckoo has a diet typical of a smaller-sized bird, consisting mainly of insects. They consume a variety of insects, including beetles, caterpillars, grasshoppers, ants, bees, wasps, cicadas, and damselflies.

They may also eat fruits and small berries. Studies have shown that the bird has a preference for termites, consuming them in significant number when available in their habitat.

Metabolism and Temperature Regulation

Metabolic rates of smaller birds are proportionally higher than larger birds due to their higher surface-area-to-volume ratio. This compensation in metabolism enables small birds to meet their energy demands given their smaller body size.

Birds have a unique method of regulating their temperature, called thermoregulation. Thermoregulation relays on the bird’s metabolic rate and the insulation provided by its feathers.

Feathers help keep heat in, reducing the amount of energy expenditure needed to maintain optimum body temperate.

Sounds and Vocal Behavior


The Square-tailed Drongo-Cuckoo is a mostly silent bird that may occasionally make a double-noted whistle, a single-note whistle, or harsh buzzing calls. The song is a double-noted whistling, Whoo-eup, whio-eup, or sometimes described as pyoo, in a rapid-fire sequence, which is repeated two to six times.

Occasionally, the bird can be heard throughout the day, producing its vocalization of a Pix sound. Its call in a nearby presence is described as a rattling, muffled Krr-krr-krr sound.

The calls of the Square-tailed Drongo-Cuckoo are similar to those of other drongo-cuckoos in their range, such as the Fork-tailed Drongo-Cuckoo, the Lesser Racket-tailed Drongo, and the Greater Racket-tailed Drongo. The bird’s call is more intense during the breeding season, when males defend their territories and attract potential mates.

It is worth noting that the calls of the Square-tailed Drongo-Cuckoo are distinct from a similar cuckoo species, the Plaintive Cuckoo, which produces a different type of double-noted whistling call, often described as three-and-one-half-whistles, that is more plaintive in tone.


The Square-tailed Drongo-Cuckoo is a small bird, with a diet that consists mainly of insects and occasionally small berries and fruits. As with other birds, the Square-tailed Drongo-Cuckoo has high metabolic rates relative to its body mass, enabling it to meet its energy demands.

The bird’s vocalizations are double-noted whistles, with a unique Whoo-eup, whio-eup song. This song is critical to the breeding season when males defend their territories and attract potential mates.

The Square-tailed Drongo-Cuckoo’s vocalization is distinct from other birds within its range and is an intricate feature of its vocal behavior.



The Square-tailed Drongo-Cuckoo is an agile flyer, moving swiftly among the trees and canopy. The bird performs short hops and flits from branch to branch.

They are known for their ability to hover momentarily, allowing them to catch insects in mid-air.

Self Maintenance

The Square-tailed Drongo-Cuckoo, like other birds, preens itself regularly to maintain its plumage and hygiene. The bird uses its beak to clean its feathers, straightening and aligning them.

This helps to keep their feathers properly oriented, allowing them to maintain their insulating properties.

Agonistic Behavior

The Square-tailed Drongo-Cuckoo is known for exhibiting agonistic behavior. The bird is aggressive towards other drongo-cuckoo species and will defend its territory from intruders.

During combat, the bird spreads its wings and raises its crest, making itself appear larger and more intimidating. They may also use bills in combat, pecking and biting the intruder.

Sexual Behavior

The Square-tailed Drongo-Cuckoo is polygynandrous, meaning that both males and females mate with multiple partners. Males will defend territories during the breeding season and will court females with their display flight.

The bird’s courtship involves a series of aerial displays and calling, which attracted potential mates. Once a male has attracted a female, the pair will mate and then separate.

The female will then lay its eggs in the host nest, with minimal further involvement from the male.


The breeding season of the Square-tailed Drongo-Cuckoo in most of its range is from March to June, although there is evidence that this time period extends until July. The bird is a brood parasite, laying its eggs in the hosts’ nests, typically the Common Iora, the Red-vented Bulbul, and the Black-crested Bulbul.

The chick remains in the host’s nest for about 16 to 25 days. After leaving the nest, the young birds are independent and require no further care from their parents.

Demography and Populations

The Square-tailed Drongo-Cuckoo is generally considered to be a species of least concern but has suffered some declines in certain regions due to habitat loss. The population of the bird is thought to be stable, and there are no current conservation efforts specifically targeting the species.

There is a global estimate of 1-10 million individual Square-tailed Drongo-Cuckoos worldwide. The breeding range of the species expands from the southeastern Himalayas to southern China to Java.

Its breeding range size covers approximately 12.9 million square kilometers, which is very large in comparison to many other species of birds. Information about specific populations of the bird is sparse and limited.

More studies are needed on population numbers localized to their ranges. As most of the habitats in which the Square-tailed Drongo-Cuckoo lives are under threat of deforestation and degradation, information regarding the species’ demographic parameters would be beneficial for developing conservation measures.


The Square-tailed Drongo-Cuckoo is an active species, with agile flight and aggressive behavior toward other cuckoo-doves in their range. They are polygynandrous and follow complex sexual and breeding behavior.

Polygynandrous birds are unusual, which adds to the complex and interesting nature of the species. The bird is a brood parasite, laying its eggs in the nests

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