Disentangling olfactory and visual information used by field foraging birds

Foraging strategies of birds can influence trophic plant-insect networks with impacts on primary plant production. Recent experiments show that some forest insectivorous birds can use herbivore induced plant volatiles (HIPVs) to locate herbivore-infested trees, but it is unclear how birds combine or prioritise visual and olfactory information when making foraging decisions. Here we investigated attraction of ground-foraging birds to HIPVs and visible prey in short vegetation on farmland in a series of foraging choice experiments. Birds showed an initial preference for HIPVs when visual information was the same for all choice options (i.e. one experimental setup had all options with visible prey, another setup with hidden prey). However, if the alternatives within an experimental setup included visible prey (without HIPV) in competition with HIPV-only, then birds preferred the visual option over HIPVs. Our results show that olfactory cues can play an important role in birds’ foraging cho...