Predation of arctic fox (<Emphasis Type="Italic">Vulpes lagopus</Emphasis>) pups by common ravens (<Emphasis Type="Italic">Corvus corax</Emphasis>)

Identifying correctly trophic interactions is important for understanding population dynamics and ecosystem functioning. However, some predator–prey relationships may still remain undetected, due to the difficulty of observing rare predation events. We report the first observation of predation of arctic fox (Vulpes lagopus) pups by common ravens (Corvus corax). The predation event was witnessed on Bylot Island, Nunavut, Canada, through an automatic camera placed on a den. On June 8, 2013, the day following pup emergence from the den, the complete litter of four was killed and taken away by a pair of ravens despite the intermittent presence of the mother. This event lasted 2.5 h, occurred during a low lemming year, and resulted in the fox pair failing their reproduction. Only two other fox litters were present that summer in our 600 km² study area, so this litter predated by ravens accounted for 25 % (4/16) of the pups produced. Our report shows how continuous monitoring of dens using automatic cameras can allow documentation of rare events. In addition to food competition and cache raiding, pup predation contributes to the antagonistic interactions between arctic foxes and ravens in the High Arctic, which may intensify during low lemming years. This observation allows a better understanding of species interactions within the Arctic predator guild.