Pigeons integrate past knowledge across sensory modalities

Abstract

Advanced inferring abilities that are used for predator recognition and avoidance have been documented in a variety of animal species that produce alarm calls. In contrast, evidence for cognitive abilities that underpin predation avoidance in nonalarm-calling species is restricted to associative learning of heterospecific alarm calls and predator presence. We investigated cognitive capacities that underlie the perception and computation of external information beyond associative learning by addressing contextual information processing in pigeons, Columba livia, a bird species without specific alarm calls. We used a habituation/dishabituation paradigm across sensory modes to test pigeons' context-dependent inferring abilities. The birds reliably took previous knowledge about predator presence into account and responded with predator-specific scanning behaviour only if predator presence was not indicated before or if the perceived level of urgency increased. Hence, pigeons' antipredator behaviour was not based on the physical properties of displayed stimuli or their referential content alone but on contextual information, indicated by the kind and order of stimulus presentation and different sensory modes.

Keywords: Columba livia; contextual understanding; cross-modal recognition; pigeon; predator recognition; response urgency.

Figure A1

Spectrograms of acoustic stimuli: (a) buzzard territory calls, (b) pheasant territory calls.

Figure 1

Visual stimuli. Stuffed models of (a) a common buzzard and (b) a pheasant. (c) Both visual stimuli were presented to the pigeons in a cardboard box.

Figure 2

Number of trials the pigeons needed to habituate to pheasant and buzzard stimuli. Box plots in grey indicate acoustic playbacks; box plots in white refer to visual models. Numbers represent the number of dyads that were habituated with each stimulus. *Statistical significance after Bonferroni corrections (P < 0.013). Boxes indicate the first and third quartiles. The horizontal line within each box represents the median. Whiskers include values that amount to 1.5 times the height of the box (interquartile range).

Figure 3

Estimated (a) vigilant and (b) predator-specific responses at the end of the baseline phase (white bars), at the end of the habituation phase (grey bars) and during the dishabituation phase (black bars). Abbreviations below group numbers indicate the stimuli presented during the habituation and the dishabituation phases (ph vis = pheasant model; ph ac = pheasant calls; buz vis = buzzard model; buz ac = buzzard calls). Asterisks indicate significant differences between behavioural responses in the habituation and the dishabituation phases (one-tailed P values <0.05) and were obtained by calculating Wilcoxon signed-ranks tests by hand and comparing the test statistic (T) with critical values from tables.