Wild skuas can use acoustic cues to locate hidden food

Abstract

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Responses of wild skuas (Catharacta antarctica ssp. lonnbergi) to human cues in cooperative and competitive social contexts.

“…Due to the significant physical effort associated with chick rearing, birds might be less prone to participate in cognitive experiments (Ibañez et al, 2018). However, as shown by other cognitive experiments carried out during the breeding season (e.g., Danel et al, 2021Danel et al, , 2022a, including Experiment 2, skuas are in fact strongly motivated to get the food reward and to interact with a human experimenter. Thus, it seems more likely that, due to their inability to use the experimenter's cues and the resulting failures in obtaining rewards, skuas increasingly lost motivation.…”

“…Skuas might indeed be more willing to participate if they see the food reward directly, such as in Experiment 2. However, although the experimenter had to increase the administration of training trials through the experiments, lack of motivation was evident neither during the training phase, nor during other cognitive tasks performed subsequently where the food reward was covered (e.g., Danel et al, 2022a). The genetic proximity between gulls and skuas (Furness et al, 2020) also leads us to preclude the explanation that skuas are unable to see properly human experimenters’ cues due to limited vision.…”

“…In two conditions (i.e., face occluded/ chest occluded and mouth occluded/eyes occluded; Figure 1), each experimenter used one piece of opaque dark blue polar fleece fabric (20 cm in width, 20 cm in length). The food reward consisted of a fresh piece of trout (Salmo trutta, about 3 g), known to be of particularly high value to the birds (e.g., Danel et al, 2021Danel et al, , 2022a. The trout (an introduced alien in Kerguelen) was fished in Kerguelen Islands' rivers and streams and was frozen 3-5 weeks before the start of the experiments, to be unfrozen 2 hr before the start of the experimental sessions.…”

“…Contact with humans was rare on île Verte before 2019-2020, the breeding season in which the first preliminary avian cognitive studies started to be conducted on the island. Interestingly, skuas are fast learners (e.g., Danel et al, 2021Danel et al, , 2022a, not neophobic toward humans or experimental apparatuses (e.g., Lee et al, 2016), highly motivated by food (e.g., Danel et al, 2021Danel et al, , 2022a, and inclined to participate in experiments (ensuring almost full participation of individuals; e.g., Danel et al, 2021Danel et al, , 2022a, which makes them useful models for field studies (Janmaat, 2019;Shaw et al, 2015). Wild brown skuas thus represent an ideal model to allow field comparisons with urban herring gulls in the context of interspecific communication.…”

Inter-species stimulus enhancement: herring gulls ( Larus argentatus ) mimic human food choice during foraging

“…Wild brown skuas ( Catharacta antarctica ssp. lonnbergi ), another kleptoparasitic seabird, prefer food that has previously been handled by an experimenter [ 44 ] and can follow human behavioural cues [ 45 ], which raises questions as to whether frequent contact with humans is a prerequisite for the exploitation of human cues or simply a facilitator, as kleptoparasites may possess a general tendency for paying attention to heterospecific cues.…”