Researchers from the Mohamed bin Zayed Raptor Conservation Fund (MBZRCF) and the Mongolian Bird Conservation Center have documented an exceptionally rare three-egg clutch in a wild Bearded Vulture (Gypaetus barbatus) nest, providing one of the few confirmed records of this phenomenon worldwide.
Abu Dhabi, UAE: The Mohamed bin Zayed Raptor Conservation Fund (MBZRCF) is pleased to share the publication of a remarkable new peer-reviewed study led by Amarkhuu Gungaa, Altangerel Tsogtmagnai, Amartuvshin Purevdorj, and Andrew Dixon (MBZRCF).
Published in Vulture News, the study presents the first photographic evidence from Mongolia of a Bearded Vulture nest containing three eggs, captured using drone imagery. Bearded Vultures are an obligately siblicidal species that normally lay one or two eggs, making this observation exceptionally rare. The researchers could identify only one other authenticated record of a three-egg clutch, documented in India more than 150 years ago.
What the team found
- The first confirmed photographic record from Mongolia of a wild Bearded Vulture nest containing three eggs.
- Drone imagery allowed researchers to safely document the nest without disturbing the breeding birds.
- One chick successfully hatched from the clutch and was monitored through subsequent development.
- Historical records indicate that three-egg clutches are extraordinarily rare, with only one authenticated observation previously reported in India in 1870.
- A review of museum egg collections suggests that two-egg clutches were historically more common in Asian populations than in Europe, although historical collections may not accurately reflect natural clutch sizes.
“This remarkable observation demonstrates the value of modern drone technology in documenting rare breeding events while minimizing disturbance to wildlife. Even for well-known species, careful field monitoring continues to reveal important aspects of their breeding biology.” said Andrew Dixon, corresponding author and researcher at the Mohamed bin Zayed Raptor Conservation Fund.
For MBZRCF, the discovery highlights the importance of long-term field monitoring and international collaboration in improving our understanding of rare species. Observations such as these contribute valuable information to the global knowledge of Bearded Vulture biology and reproduction.
“Every rare observation adds another piece to the puzzle of understanding these remarkable birds,” said His Excellency Mr. Abdulla Ahmed Al Qubaisi, Managing Director of the Mohamed bin Zayed Raptor Conservation Fund. “By combining innovative monitoring techniques with strong international partnerships, we continue to strengthen the scientific foundation needed for the long-term conservation of raptors across their range.”
Why this matters
The Bearded Vulture is one of the world’s most distinctive birds of prey, renowned for its specialised bone-based diet and slow reproductive strategy. Because the species typically produces only a single surviving chick, documenting an extremely unusual three-egg clutch provides valuable insight into breeding variation and reproductive biology. The study also demonstrates how drone technology can safely support wildlife research, helping scientists monitor inaccessible nests while minimizing disturbance to breeding birds. Together, these findings contribute to improving conservation knowledge and informing future research on this iconic mountain raptor.
Partners and acknowledgements
This study was conducted through collaboration between the Mohamed bin Zayed Raptor Conservation Fund and the Mongolian Bird Conservation Center. The authors acknowledge the field teams whose careful monitoring and drone surveys made this rare observation possible and thank all collaborators who contributed to advancing knowledge of Bearded Vulture ecology and conservation.
