Resource partitioning in two shrike species during autumn migration in Cyprus

The coexistence of closely related sympatric species is based on ecological processes that enable their spatial or temporal separation. Among birds, the analysis of resource partitioning mechanisms has predominantly focused on breeding birds, although migratory birds also face limitations, primarily due to conditions encountered at stopovers along migration routes. In the present study, the habitat use and foraging behaviour of two shrike species, the Red-backed Shrike (Lanius collurio) and Masked Shrike (Lanius nubicus), were studied during peak migration in Cyprus, in September 2022 and 2023. Seven study sites were selected, with five located along the coast and two inland. Habitat data were based on measurements within a 100 m radius plot centered on the site where the shrike was observed (n = 82 sites). Behavioural parameters included height of perch used, perch type and hunting success (n = 310). Generally, only subtle differences in habitat utilization were observed among these shrike species. Red-backed Shrike occurred closer to the coast than Masked Shrike, while Masked Shrike sites included more orchards. No differences in prey size or hunting success were found between the shrike species. The results may be attributed to an abundant food supply, allowing different shrike species to share resources and, consequently, leading to considerable ecological niche overlap.