Black‐winged Stilt (Himantopus himantopus) – A Detailed Study

Taxonomy

• Kingdom: Animalia
• Phylum: Chordata
• Class: Aves
• Order: Charadriiformes
• Family: Recurvirostridae
• Genus: Himantopus
• Species: Himantopus himantopus

Morphology & Identification

The Black-winged Stilt (Himantopus himantopus) is a striking wader with the following distinguishing features:

• Size: Approximately 33–36 cm in length.
• Wingspan: Around 75 cm.
• Legs: Exceptionally long, slender, and pink or reddish in color, which helps them wade through shallow waters.
• Beak: Long, thin, and straight black beak, adapted for foraging small invertebrates.
• Plumage:
  • Upperparts: Glossy black wings and back.
  • Underparts: Bright white, providing a stark contrast.
  • Head: Mostly white, sometimes with black markings in certain subspecies or during different stages of plumage.
• Eyes: Dark, with a distinctive red iris that enhances its striking appearance.

Habitat & Distribution

General Distribution

The Black-winged Stilt has a wide geographical range and is found across:

• Europe
• Asia
• Africa
• Australia
• South America

It is commonly seen in wetlands, marshes, lagoons, mudflats, and shallow water bodies.

Presence in India

In India, it is widely distributed across wetlands, freshwater lakes, brackish water zones, and coastal estuaries.

Presence in Sundarban

The Sundarban region provides an ideal habitat for the Black-winged Stilt due to its intertidal mudflats, mangrove creeks, estuarine waters, and shallow brackish swamps.

• This bird is frequently sighted in the tidal mudflats and the shallow water edges of mangroves.
• It forages in low-salinity zones where small crustaceans, insects, and larvae are abundant.
• During winters, migratory populations increase in the Sundarban biosphere.

Special Ecological Role in Sundarban

• Indicator of Wetland Health: The presence of this species reflects the health of Sundarban’s wetland ecosystem, as it thrives in unpolluted, biologically rich waters.
• Predator of Aquatic Invertebrates: Helps in controlling insect larvae, crustaceans, and small mollusks, contributing to the ecosystem’s food web.
• Affects Nutrient Cycling: By stirring up sediments while foraging, it enhances aeration and nutrient recycling in the shallow waters.

Feeding Behavior

• The Black-winged Stilt primarily feeds on small invertebrates, including:
  • Aquatic insects
  • Small crustaceans
  • Mollusks
  • Worms
  • Small fish
• Foraging Technique:
  • Uses its long beak to probe into the soft mud or shallow waters.
  • Often seen wading in water, picking prey from the surface.
  • Sometimes, it exhibits a rapid pecking behavior in shallow water.

Breeding & Nesting

• Breeding Season: Typically March to August (varies based on region).
• Nesting Sites:
  • Prefers small islands in lakes, marsh edges, or undisturbed sandy banks.
  • In the Sundarban, it chooses raised muddy banks or drier patches near mangrove wetlands.
• Nesting Structure:
  • Scrapes out a small depression in the ground, lining it with grass, pebbles, or shells.
• Eggs & Incubation:
  • Lays 3–5 eggs, which are pale buff with dark blotches.
  • Both male and female share incubation duties for about 22–25 days.
• Chick Development:
  • Chicks are precocial, meaning they can walk and follow parents soon after hatching.
  • They fledge in about 4–5 weeks.

Behavioral Traits

• Highly Social: Often seen in small to large flocks, especially outside the breeding season.
• Aggressive Defense: If disturbed near nesting sites, adults exhibit alarm calls and aerial displays to distract predators.
• Territoriality: During breeding, they defend their nesting area aggressively against other birds.

Conservation Status

• IUCN Status: Least Concern (LC)
• Major Threats:
  • Habitat destruction due to wetland degradation, pollution, and human encroachment.
  • Disturbance from tourism and fishing activities.
  • Climate Change affecting water levels in wetland habitats, including the Sundarban ecosystem.

Conservation in Sundarban

• Protected within Sundarban Biosphere Reserve, which ensures a safe breeding and foraging ground.
• Mangrove conservation efforts indirectly help maintain this species’ habitat.
• Monitoring programs are in place to track population trends in the region.

Conclusion

The Black-winged Stilt (Himantopus himantopus) is an elegant wader with significant ecological importance in wetland and estuarine ecosystems. Its presence in the Sundarban highlights the region’s biodiversity and the need for wetland conservation. As an indicator species, its well-being is linked to the health of the Sundarban’s delicate ecosystem. Conservation efforts focusing on wetland protection and pollution control will ensure that this beautiful bird continues to thrive in India’s most unique mangrove habitat.