Data from: Insectivorous birds can see and smell systemically herbivore‐induced pines

<p>Several studies have shown that insectivorous birds are attracted to herbivore-damaged trees even when they cannot see or smell the actual herbivores or their faeces. However, it often remained an open question whether birds are attracted by herbivore-induced changes in leaf odour or in leaf light reflectance or by both types of changes. Our study addressed this question by investigating the response of great tits (<em>Parus major</em>) and blue tits (<em>Cyanistes caeruleus</em>) to Scots pine (<em>Pinus sylvestris</em>) damaged by pine sawfly larvae (<em>Diprion pini</em>). We released the birds individually to a study booth, where they were simultaneously offered a systemically herbivore-induced and a non-infested control pine branch. In the first experiment, the birds could see the branches, but not smell them, because each branch was kept inside a transparent, air-tight cylinder. In the second experiment, the birds could smell the branches, but not see them, because each branch was placed inside a non-transparent cylinder with a mesh lid. The results show that the birds were more attracted to the herbivore-induced branch in both experiments. Hence, either type of the tested cues, the herbivore-induced visual plant cue alone as well as the olfactory cues <em>per se</em>, is attractive to the birds.</p>