Assessing the spontaneous use of human-given cues in ground-hornbills.

A wide range of species relies on heterospecific visual cues to detect the location of resources like food. Although different hypotheses have been suggested to explain the emergence of this capacity in animals, results are often difficult to interpret due to the influence of other factors, such as close contact with humans. In this study, we presented eight Southern ground-hornbills (Bucorvus leadbeateri) with a two-way object-choice paradigm. The human experimenter provided a static and salient cue indicating which of the two containers was baited in four experimental conditions: (a) Touch, (b) Head, (c) Point + Head, and (d) Point. In an additional control condition (no cues given), we assessed whether subjects relied on olfactory cues to solve the task. Overall, our subjects did not spontaneously use human-given cues and their performance fluctuated near chance during the control condition. Noteworthy, most birds exhibited a side bias towards one container. We do not exclude the possibility that this species may be capable of using other cue types, or learning to use cues, after long interaction with humans is provided.