In early autmn, when birds begin to migrate, the nose-horned vipers in the Balkan Peninsula perform a very uniwue behavior. While preying mainly on terrestrial species, they move to the branches in hopes for arboreal prey. During this time they can be found between half a meter from the ground in bushes, up to several metres in the trees. They do not move for days, enduring hot and sunny days, followed by cold and rainy nights. They must be patient and cryptic to reach their goal: the final meal of the season, before hibernation.
This behavior can mainly be seen in areas, where migratory birds rest: along linear structures in the coastline, in river canyons, creeks and around water sources. Any structure in the landscape that may attract birds is welcome. All ages of vipers can be found. While the adults specialize in ambushing birds, the juveniles and subadults feast on grasshoppers, that swarm during this season. No one knows if this behavior is an instinct or has even been learned from observation, possibly even being a social behavior.
