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Square-tailed Drongo-cuckoo

Least Concern

Surniculus lugubris

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About

The Square-tailed Drongo-cuckoo is a small, glossy black cuckoo that mimics the appearance and behavior of drongos, particularly the Black Drongo. It is known for its brood parasitic breeding strategy and its distinctive, often melancholic, calls. Its drongo-like appearance helps it to blend in with flocks of drongos, potentially aiding in its parasitic lifestyle.

Size & lifespan

Length
23-25 cm
Wingspan
Approximately 35-40 cm
Weight
30-40 g
Lifespan
Unknown in the wild, likely several years
Diet
Insectivore

Physical characteristics

Plumage
Adults are entirely glossy black, often with a bluish or purplish sheen in good light. The tail is square-ended, lacking the deeply forked tail of true drongos. Some individuals may show a small white patch on the nape, though this is often concealed or absent.
Beak shape
Slender, slightly decurved, and black.
Eye color
Dark brown to reddish-brown, with a black orbital ring.
Leg color
Blackish-grey to black.
Distinguishing features
Its overall glossy black plumage, square-ended tail (not forked like drongos), and distinctive calls are key. The lack of a prominent crest or deeply forked tail distinguishes it from drongos. The small white nape patch, if present, is a good field mark.
Juvenile appearance
Juveniles are duller black, often with some white barring or spotting on the underparts and wing coverts, and sometimes a more prominent white nape patch. The tail may be slightly less square and more rounded at the tips.
Seasonal changes
No significant seasonal plumage changes.
Sexual dimorphism
Males and females are monomorphic in plumage.

How to identify

  1. 1

    Plumage

    Look for an entirely glossy black bird. The sheen can appear bluish or purplish in sunlight.

  2. 2

    Tail Shape

    Crucially, observe the tail. It should be square-ended, not deeply forked like a true drongo. This is the most reliable field mark to distinguish it from drongos.

  3. 3

    Vocalizations

    Listen for its distinctive, melancholic 'wi-wi-wi' or 'pee-pee-pee-pee' calls. These are very different from drongo calls.

  4. 4

    Behavior

    Observe its foraging style (gleaning insects) and its tendency to associate with mixed-species flocks, particularly drongos.

  5. 5

    Nape Patch

    If visible, a small white patch on the nape can be a good indicator, though it's often concealed or absent in adults.

Habitat & range

Biomes
Tropical and subtropical moist broadleaf forests, secondary forests, forest edges, plantations, and sometimes gardens.
Geographic range
Widely distributed across the Indian subcontinent, Southeast Asia, and parts of East Asia. This includes countries like India, Nepal, Bangladesh, Myanmar, Thailand, Laos, Cambodia, Vietnam, Malaysia, Singapore, Indonesia (Sumatra, Borneo, Java, Bali, Sulawesi), and the Philippines.
Elevation range
Typically found from lowlands up to about 1,500 meters (occasionally higher).
Preferred environments
Prefers areas with dense tree cover, often near the canopy or mid-story, but can also be seen in more open woodland and cultivated areas with scattered trees.

Behavior

Activity time
Diurnal.
Feeding habits
Primarily insectivorous, feeding on a variety of insects including caterpillars, grasshoppers, beetles, and ants. It forages by gleaning insects from foliage and branches, and occasionally makes aerial sallies to catch flying insects. It often associates with mixed-species foraging flocks.
Social behavior
Generally solitary or found in pairs. It is often seen associating with drongos, which it mimics, and other mixed-species foraging flocks.
Flight pattern
Direct and strong flight, often with rapid wing beats. It can be quite agile when pursuing insects.
Migration pattern
Mostly resident throughout its range, but some populations in the northern parts of its distribution may undertake short-distance altitudinal or local migrations. Some populations in Southeast Asia are considered partial migrants.
Territoriality
Brood parasitic, so it does not maintain a nesting territory. However, individuals may defend foraging areas or perching sites.

Song & calls

Song
Its song is a series of clear, plaintive, often descending whistles or 'wi-wi-wi' notes, sometimes described as melancholic or mournful. It can be quite repetitive and distinctive, often given from a prominent perch.
Call
Calls include sharp 'chip' notes, and a characteristic 'pee-pee-pee-pee' or 'pi-pi-pi-pi' series, often accelerating and rising in pitch. It also has a 'kwee-kwee-kwee' call.
When they vocalize
Most vocal during the breeding season, typically in the early morning and late afternoon, but can be heard throughout the day.

Breeding & reproduction

Breeding season
Varies geographically, generally coinciding with the breeding season of its host species. In India, typically March-August; in Southeast Asia, often April-July.
Nesting habits
Brood parasitic. It lays its eggs in the nests of other bird species, primarily drongos (e.g., Black Drongo, Ashy Drongo) and sometimes other small passerines. The female lays a single egg per host nest.
Clutch size
One egg per host nest, but a female may lay multiple eggs in different host nests over a breeding season.
Egg description
Eggs are typically pale blue or greenish-blue, sometimes with reddish-brown spots or streaks, mimicking the eggs of its host species. Size is approximately 20-23 mm x 15-17 mm.
Incubation period
Approximately 12-14 days, similar to its host species.
Fledging period
Chicks fledge around 18-20 days after hatching, often ejecting host eggs or chicks from the nest.
Parental care
No parental care is provided by the cuckoo itself; the host parents raise the cuckoo chick.

Where to find

Forest Edges

Often found at the interface between dense forest and more open areas, where it can forage and observe potential host nests.

Secondary Forests

Common in regenerating forests and disturbed habitats, which often have a good mix of tree cover and open spaces.

Plantations and Gardens

Can be seen in cultivated areas with mature trees, especially if adjacent to natural forest patches.

Canopy and Mid-story

Typically perches in the mid-to-upper canopy of trees, often on exposed branches, making it easier to spot.

Field tips

  1. Listen for calls. Its distinctive calls are often the first indication of its presence. Learn to recognize its melancholic whistles.
  2. Scan mixed flocks. Look for it among flocks of drongos, as it often mimics their appearance and behavior to blend in.
  3. Observe tail shape carefully. When you see a glossy black bird, pay close attention to the tail. A square tail is key to identification.
  4. Check prominent perches. It often perches on exposed branches in the mid-to-upper canopy, making it easier to spot against the sky.

Similar species

Fork-tailed Drongo-cuckoo

Surniculus dicruroides

The Fork-tailed Drongo-cuckoo (now often considered a subspecies or part of a species complex with S. lugubris, but historically treated separately) has a distinctly forked tail, though less deeply forked than true drongos. S. lugubris has a square-ended tail. Vocalizations also differ.

Black Drongo

Dicrurus macrocercus

True drongos like the Black Drongo have a deeply forked tail and a more robust, slightly hooked bill. While also glossy black, their flight and calls are different. The Square-tailed Drongo-cuckoo's tail is square, not forked.

Ashy Drongo

Dicrurus leucophaeus

Ashy Drongos are typically grey, not glossy black, and have a deeply forked tail. While some subspecies can be darker, their overall coloration and tail shape distinguish them.

Quick facts

Mimicry:
Mimics drongos in appearance and behavior.
Breeding Strategy:
Brood parasite, lays eggs in drongo nests.
Tail Shape:
Square-ended tail, distinguishing it from forked-tailed drongos.
Diet:
Primarily insectivorous.
Vocalization:
Melancholic, whistling calls.

Fun facts

  • The genus name 'Surniculus' is derived from 'Surnus' (an old name for a cuckoo) and 'niculus' (meaning small), referring to its small cuckoo size.
  • Its drongo-like appearance is a classic example of Batesian mimicry, where a harmless species mimics a more aggressive or unpalatable one (drongos are known for their aggressive defense of nests).
  • The 'Wiwik Uncuing' name in Indonesian refers to its call ('wiwik') and its square tail ('uncu' meaning short or blunt, referring to the tail).
  • Despite its widespread distribution, it can be surprisingly difficult to spot due to its secretive nature and its ability to blend in with drongo flocks.

Scientific classification

Kingdom
Animalia
Phylum
Chordata
Class
Aves
Order
Cuculiformes
Family
Cuculidae
Genus
Surniculus
Species
Surniculus lugubris

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