The Barbary falcon differs in appearance from the peregrine falcon according to Gloger's rule. The genetic distance is slight and the species form a close-knit and somewhat paraphyletic group in DNA sequence analyses. In fact, some taxonomic authorities consider it conspecific. They differ more in behavior, ecology and anatomy than usual for conspecifics. They are able to produce fertile hybrids, but they are generally allopatric and only co-occur during breeding season in small areas such as the Maghreb, the Punjab, Khorasan and possibly the Mongolian Altai and there is clear evidence of assortative mating, with hybridization hardly ever occurring under natural conditions. In short, though they occupy adjacent territories, they breed at different times of the year and Barbary falcons virtually never breed with peregrine falcons in nature.