Evolutionary Relationships and Genetic Diversity in the Southern Siberian Populations of the Saker Falcon (Falco cherrug), a Young and Endangered Species

Studying intraspecific differentiation in closely related species is essential to clarify the phylogenetic relationships and mechanisms of early stage speciation, particularly in evolutionarily young lineages affected by human-driven population declines. The endangered saker falcon (Falco cherrug), with its ambiguous phylogenetic links to the gyrfalcon (F. rusticolus), exemplifies this scenario. This study presents a comprehensive genetic analysis of F. cherrug and F. rusticolus using mtDNA markers and microsatellite loci, focusing on the diversity of southern Siberian saker falcon populations. The genotyping results for these populations were correlated with phenotypic data obtained from long-term monitoring (1999–2021). Our findings provide novel insights into the current subspecific differentiation and the remnants of a nascent subspecies structure that existed before the recent demographic collapse. Furthermore, our results support the hypothesis of the gyrfalcon’s origin as a descendant species of the Asian saker falcon, i.e., an evolutionarily young lineage undergoing divergence. Our data contribute to the understanding of the Hierofalco evolutionary history, particularly through the analysis of heterogeneous mutation rates among mitochondrial haplogroups. This study underscores the critical importance of conservation efforts for wild endangered populations through long-term monitoring integrated with combined genetic approaches.