Exclusion in the field: wild brown skuas find hidden food in the absence of visual information

Abstract

Inferential reasoning by exclusion allows responding adaptively to various environmental stimuli when confronted with inconsistent or partial information. In the experimental context, this mechanism allows selecting correctly between an empty option and a potentially rewarded one. Recently, the increasing reports of this capacity in phylogenetically distant species have led to the assumption that reasoning by exclusion is the result of convergent evolution. Within one largely unstudied avian order, i.e. the Charadriiformes, brown skuas (Catharacta antarctica ssp lonnbergi) are highly flexible and opportunistic predators.Behavioural flexibility, along with specific aspects of skuas' feeding ecology, may act as influencing factors in their ability to show exclusion performance. Our study aims to test whether skuas are able to make choice by exclusion in a visual two-way object-choice task.Twenty-six wild birds were presented with two opaque cups, one covering a food reward.Three conditions were used: 'full information' (showing the content of both cups), 'exclusion' (showing the content of the empty cup), and 'control' (not showing any content).Skuas preferentially selected the rewarded cup in the full information and exclusion condition. The use of olfactory cues was excluded by results in the control condition. Our study highlights the cognitive potential of this predatory seabird and opens new investigations for testing further its cognition in the wild.

Waterbird solves the string-pull test

“…Indeed, we are aware of only four studies that have experimentally tested waterbird cognition. These include two studies that experimentally tested the problem-solving skills of waterbirds (Olrog's gull: [ 23 ] brown skua: [ 24 ]), though neither employed the string-pull test paradigm. A third study showed a small number of horned puffins ( Fratercula corniculate , n = 5) to be unsuccessful at an object permanence test [ 60 ] which tests whether an individual comprehends that an object continues to exist when it is suddenly hidden from view [ 61 , 62 ].…”

“…Danel et al . [ 24 ] tested 26 free-living brown skuas ( Catharacta antarctica ssp. lonnberg ) with an exclusion test in which each subject was presented with two opaque cups—one empty and one containing food.…”

“…lonnberg ) with an exclusion test in which each subject was presented with two opaque cups—one empty and one containing food. Subjects correctly chose the baited cup over the empty cup 74% of the time if they had been shown the contents of both cups beforehand, and 64% of the time if they had been shown the empty cup only [ 24 ]. Despite the paucity of cognitive testing, waterbirds are suspected to display behaviours often associated with advanced cognition, including possible tool-use in southern black-backed gulls ( Larus dominicanus ) [ 25 ], and bait-fishing in herring gulls ( Larus argentatus ) [ 26 ] and several species of heron and egret (family Ardeidae) [ 27 – 31 ].…”

“…Castano et al [23] reported that none of the 53 free-living Olrog's gulls (Larus atlanticus) that showed interest in a transparent box containing food could open the lid to retrieve the food. Danel et al [24] tested 26 free-living brown skuas (Catharacta antarctica ssp. lonnberg) with an exclusion test in which each subject was presented with two opaque cups-one empty and one containing food.…”

Great Tits Learn Odors and Colors Equally Well, and Show No Predisposition for Herbivore-Induced Plant Volatiles

“…Even though olfaction previously has been dismissed as being unimportant for most bird species, it has turned out to play an important role in bird foraging behavior (Mäntylä et al, 2004;Hiltpold and Shriver, 2018;Potier, 2020;Danel et al, 2021). Some bird species can use their sense of smell to identify caterpillarinfested trees by detection of herbivore induced plant volatiles (HIPVs) (Mäntylä et al, 2004(Mäntylä et al, , 2020Amo et al, 2013).…”