Status and trends of circumpolar peregrine falcon and gyrfalcon populations

The peregrine falcon (Falco peregrinus) and the gyrfalcon (F. rusticolus) are top predators of arctic ecosystems and have been identified as Focal Ecosystem Components (FEC) for the Arctic Council’s pan-Arctic biodiversity monitoring plan. We provide the first overview of contemporary arctic falcon monitoring sites, and present trends for selected FEC attributes estimated using General Additive Models. Monitoring sites (n=24) ranged in size from 100 to 84000 km2, and were uniformly distributed throughout the circumpolar-arctic except for eastern Russia. Fourteen projects spanned more than 30 years, and 21 were active as of 2017. Occupancy and productivity showed variable spatial and temporal trends with signs of declining productivity for peregrines in some areas. Gyrfalcon occupancy and productivity appeared to be stable, and was strongly associated with cyclic populations of their main prey ptarmigan (Lagopus spp.), particularly in areas without alternative prey. Differences in survey design and disparate use of terms precludes direct comparisons of FEC attributes among the entire set of monitoring sites, and emphasize the need for consistent application of standard definitions, as well as consistent data collection methods and reporting. This overview emphasizes the potential for on-going collaboration among research groups focused on monitoring Arctic falcon species.