Rare Eastern Marsh Harrier Sighting Signals Revival of Bengaluru's Hesaraghatta Grassland
One year after the Hesaraghatta Grassland on the outskirts of Bengaluru was officially notified as a conservation reserve, this last remaining grassland ecosystem in the city is steadily transforming into a thriving biodiversity hotspot. This ecological evolution offers renewed hope for conservationists and naturalists who have long advocated for the protection of such vital habitats.
Unprecedented Sighting of Rare Raptor
Underscoring this remarkable ecological revival is the recent sighting of the rare Eastern marsh harrier (Circus spilonotus) by dedicated city-based birdwatchers. This species is seldom recorded in southern India, with most documented sightings occurring along the eastern coastline, particularly near Chennai. Its presence near Bengaluru represents a highly unusual occurrence that has excited the ornithological community.
The significant sighting was made by SNS Murthy and J Harish Kumar during their weekend explorations around Hesaraghatta Lake on March 15 and 26. What initially appeared to be a routine observation of raptors later transformed into one of the rarest documented sightings in the entire region.
Discovery Details and Expert Analysis
Murthy recounted their experience: "We began our walk around the lake at 4pm and spotted several winter migrants including the Pallid harrier, Montagu's harrier, and Western marsh harrier—species commonly recorded in this area. However, at approximately 6:05pm, we noticed a distinct individual that stood out due to its bulkier build and different flight profile."
The duo successfully photographed the bird as it moved across the grassland before being chased away by other harriers. Unfortunately, follow-up visits failed to relocate the individual, making the initial documentation even more valuable.
"We were uncertain whether it was merely a variation of the Western marsh harrier or something more unusual," Murthy explained. "But experts we consulted, along with those who responded on specialized portals, confirmed it was indeed an Eastern marsh harrier based on images, flight shots, and consultation with raptor specialists. Some even suggested the possibility of it being a hybrid with the usual Western marsh harrier—an extremely rare phenomenon with limited global documentation."
Ecological Significance and Habitat Suitability
Murthy emphasized the ecological implications: "These raptors are known for their low, gliding hunting behavior over marshy and grassland habitats, which further highlights the ecological suitability of Hesaraghatta's recovering landscape."
The Eastern marsh harrier is a migratory species that breeds across northeastern China, Mongolia, southeast Siberia, and parts of Japan. A birder from south Bengaluru noted: "Their breeding season begins in April and concludes by the monsoon, with eggs hatching into young birds. Although there has been discussion about interbreeding between Western and Eastern marsh harriers, there remains very little documentation on this trend."
Conservation Implications for Bengaluru's Ecosystems
This extraordinary sighting not only highlights the ecological value of Hesaraghatta but also reinforces the urgent need to protect Bengaluru's rapidly shrinking grassland habitats. The conservation reserve status appears to be yielding positive results, creating conditions that can attract and support species not typically associated with the region.
The transformation of Hesaraghatta Grassland serves as a promising model for urban conservation efforts, demonstrating how protected areas can facilitate ecological recovery even in proximity to major metropolitan centers. This development offers valuable insights for conservation strategies across India's urban landscapes.
