White-throated Needletail (Hirundapus caudacutus) – A Comprehensive Study

Taxonomy & Classification

• Kingdom: Animalia
• Phylum: Chordata
• Class: Aves
• Order: Apodiformes
• Family: Apodidae
• Genus: Hirundapus
• Species: Hirundapus caudacutus

The White-throated Needletail (Hirundapus caudacutus), also known as the Spine-tailed Swift, is one of the fastest birds in level flight. It belongs to the Apodidae family, which includes swifts, birds highly adapted to aerial life.

Morphology & Physical Description

• Size: 19–21 cm in length
• Wingspan: 50–56 cm
• Weight: 110–120 grams
• Plumage:
  • Upperparts are dark brown with a metallic sheen
  • Underparts have a distinct white throat and belly, contrasting with darker flanks
• Head Features:
  • Broad, slightly flattened head with a short but wide beak
  • Large, dark eyes suited for aerial navigation
• Beak: Short but strong, adapted for catching insects in flight
• Legs & Feet: Extremely short; adapted for clinging to vertical surfaces rather than walking
• Tail: Features rigid needle-like tail feathers, aiding in stability during flight

Habitat & Distribution

The White-throated Needletail is a highly aerial species, preferring:

• Mountainous regions, open woodlands, and coastal cliffs
• Tropical and subtropical regions, often found in hilly terrain and river valleys
• Migratory Range:
  • Breeds in central and eastern Asia, Russia, and Siberia
  • Winters in South and Southeast Asia, including India and Australia

Presence in the Sundarban

The Sundarban, with its vast intertidal mangrove ecosystem, is not a primary breeding habitat for the White-throated Needletail, but it serves as an important stopover site during migration.

• Seen during autumn and spring migration while traveling between breeding and wintering grounds
• Occasionally sighted above mangrove forests, feeding on insects carried by coastal winds
• Prefers the open skies above river deltas, estuaries, and forest clearings

Feeding Behavior & Diet

The White-throated Needletail is an insectivorous species, relying on:

• Flying insects like beetles, moths, dragonflies, and ants
• Occasionally feeds on small spiders carried by air currents

Foraging Strategy

• Aerial hunting: Captures prey in mid-flight, often at high speeds
• Feeds in flocks, especially during migration
• Uses rapid turns and dives to catch insects with precision

Breeding & Nesting

• Breeding Season: May to July (in northern breeding range)
• Nest Sites:
  • Prefers tree hollows, cliff crevices, and sometimes man-made structures
  • Unlike other swifts, does not nest in caves
• Eggs: Lays 2–3 white eggs per clutch
• Parental Care:
  • Both parents incubate the eggs (about 25 days)
  • Chicks fledge within 6–8 weeks, becoming independent quickly

Vocalization & Communication

The White-throated Needletail produces:

• High-pitched chattering calls during flight
• Soft whistles used in social interactions and during flock movements

Special Adaptations

1. Fastest Level-flying Bird: Capable of reaching speeds up to 170 km/h (106 mph).
2. Aerial Mastery: Can stay airborne for months, feeding, drinking, and even sleeping in flight.
3. Needle-like Tail Feathers: Help in stability and maneuvering during high-speed flight.
4. Highly Efficient Wings: Long, swept-back wings reduce drag, allowing sustained gliding.

Threats & Conservation Status

• Deforestation and habitat loss reduce breeding sites
• Declining insect populations due to pesticides impact food availability
• Climate change alters migration patterns and weather conditions affecting survival

IUCN Status: Least Concern (LC)

Although globally not endangered, monitoring is necessary as habitat degradation can affect local populations. Protecting migratory corridors, including the Sundarban, is crucial.

Conclusion

The White-throated Needletail (Hirundapus caudacutus) is an extraordinary migratory swift, built for speed and agility. Though not a resident of the Sundarban, its seasonal presence highlights the region’s importance as a vital stopover for migratory birds. Conservation of mangrove forests and open flight corridors is essential to support species like this during their long journeys.