New study on rare mating behaviour of Egyptian vultures published

A new scientific paper has documented a rare and unexpected breeding behaviour among Egyptian vultures on Masirah Island, marking a significant milestone in Oman’s ongoing efforts to understand and conserve its endangered raptor species.

The study, titled “High occurrence of polygynous trios in a dense Egyptian Vulture population,” has been published in Ringing & Migration and forms part of the project Chasing Oman’s Endangered Vulture Populations, funded by Renaissance Services SAOG and implemented by the Environment Society of Oman (ESO).

Co-authored by Omani wildlife biologist Rabab al Lawati, along with lead author Ivaylo Angelov and an international team of researchers, the study reports an unusually high number of breeding trios — groups of three adult vultures forming reproductive units instead of the typical male-female pair.

Through field surveys and months of camera-trap monitoring, the research team recorded eight confirmed and probable trios, representing approximately 13.7 per cent of all known occupied breeding territories on Masirah Island. In one remarkable case, three adults — a male and two females — were recorded sharing incubation duties over a rare three-egg clutch, an observation highly unusual for this species.

According to Ivaylo Angelov (ESO), “From a conservation point of view, the finding matters because it may turn that dense and largely saturated non-migratory populations of the species (as the one in Oman) may have high prevalence of trios distributed on a much larger geographic scale, compared with our finding on the island of Masirah.

If future research turns out this to be the case, it will completely change our understanding for the demographics of the species, by adding a third bird to a significant number of breeding territories, thus increasing the adult vultures’ population number countrywide.

This would mean higher resilience of the population to withstand declines and cope in the face of an unpredictable food resource availability, that is often limited by widely spatially spread landfills, that are visited as the favored predictable food source used by the Egyptian vultures in Oman.

From an evolutionary point of view, the finding offers a fascinating insight into the adaptability of a long-lived species (up to 30 years in the wild) in the face of highly increased intraspecific competition for breeding.

This would allow lower quality individuals (presumably younger birds, or young adults) to secure a breeding territory, gain experience in breeding and in some cases participate in raising their own fledgling. As years go by and as the dominant same-sex individual of the trio declines in fitness or dies, the third member will have the possibility to become dominant.”

He added that future surveys using drones and behavioural observation could help determine the ratio between polygynous and polyandrous trios, offering deeper insight into how these complex social structures affect population dynamics.

The findings provide valuable clues about how population density, environmental pressures, and food availability may be influencing vulture breeding systems in Oman’s fragile island ecosystems.

Maia Sarrouf Wilson, Project Manager at ESO, added: “ESO will continue its extensive research and conservation efforts for Egyptian vultures, provided sufficient funding is secured, focusing on understanding key behavioural patterns, especially after revelations about their complex social structures. Outreach and community awareness are also priorities, with a focus on the role the vultures play as cleansing agents in the environment and to maintain a clean ecosystem.”

Masirah Island is home to one of the largest known populations of Egyptian vultures in Arabia, making it a key site for understanding the regional dynamics of this globally endangered species. The study’s findings add to Oman’s growing reputation as a regional hub for wildlife research and conservation science.