Mate choice and patterns of adaptive variation in Eurasian black vultures: An assessment using MHC and olfactory receptor gene analysis

The Eurasian Black Vulture, Aegypius monachus, a large raptor species of high conservation concern native to southern Europe and central Asia, is facing serious threats in the wild. An international conservation breeding program coordinated at Planckendael Animal Park, and reintroduction projects in southern Europe aim to maintain a stable captive population in European zoos while also producing enough young to be released into the wild each year, thereby re-establishing wild populations of this species in areas where it has been lost. However, the captive breeding programme has very limited success and preliminary behaviour studies and studbook analysis suggest that the absence of courtship behaviours and poor pair bond quality may be linked to the low breeding success rates.
In a broad scientific approach we are currently trying to understand the genetics underlying mate choice in this endangered species. In collaboration with multiple international partners to analyse mate choice criteria in A. monachus a special focus is set on the role of major histocompatibility complex (MHC) genes in mate preferences. Results are contrasted with information on general relationship among captive individuals and information on the birds’ health condition. These data will shed light on how MHC genotypes may impair or enhance pair bonding in captive breeding pairs, and as such possibly provide a promising tool for successful pair selection and matchmaking in the conservation breeding programme. A deep insight into the role of adaptive variation in response to how local selective constraints shape genetic differences in contemporary A. monachus will also be established. Understanding patterns of adaptive variation in A. monachus will improve the definition of conservation units for the wild population.
In addition, in close collaboration with the EEP manager and studbook coordinator for this species, Marleen Huyghe, scientifically assisted analysis of past decades of husbandry in this species aims to identify reasons for low captive breeding success. Immediate actions were also implemented, such as the construction of a “dating aviary” in Planckendael where young birds can actually choose a preferred mate, and the rematching of age-incompatible pairs resulting from these analyses including the monitoring the outcome.