Vision, touch and object manipulation in Senegal parrots
            <i>Poicephalus senegalus</i>

Demery, Zoe; Chappell, Jackie; Martin, Graham R.

doi:10.1098/rspb.2011.0374

Cited by 73 publications

(46 citation statements)

References 41 publications

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“…Parrots find food primarily using vision and use touch to skillfully extract edible parts of food, such as husking seeds (20). They palpate objects using specialized "bill-tip organs," located inside the distal upper and lower beak.…”

Section: Neoavesmentioning

confidence: 99%

Evolutionary Specialization of Tactile Perception in Vertebrates

2016

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Evolution has endowed vertebrates with the remarkable tactile ability to explore the world through the perception of physical force. Yet the sense of touch remains one of the least well understood senses at the cellular and molecular level. Vertebrates specializing in tactile perception can highlight general principles of mechanotransduction. Here, we review cellular and molecular adaptations that underlie the sense of touch in typical and acutely mechanosensitive vertebrates.

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Section: Neoavesmentioning

confidence: 99%

Evolutionary Specialization of Tactile Perception in Vertebrates

2016

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“…Given that extent of binocular overlap in Grey parrots is unknown, and can be estimated only from data on Senegal parrots (~30%, according to Demery et al, 2011), a not very closely related species, we chose to present stimuli monocularly. Interestingly, Griffin tended to shift his head so as to view stimuli with his left eye as they came into view; he did, however, potentially have a quick, initial binocular view.…”

Section: Attention and Lateralitymentioning

confidence: 99%

Robust representation of shape in a Grey parrot (Psittacus erithacus)

Pepperberg

Nakayama

2016

Cognition

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A Grey parrot, Griffin (Psittacus erithacus), previously taught English labels for various colors and shapes with respect to three-dimensional (3D) stimuli, was tested on his ability to transfer to very different two-dimensional (2D) images consisting of modal and amodal completion stimuli. For modal completion (aka subjective contours), Kanizsa figures were constructed using black 'pac-men' to form regular polygons on colored paper. For amodal completion, portions of variously colored regular 2D polygons were occluded by black circles or other black figures. For each task, Griffin provided a vocal English shape label for five possible shapes designated by their vertices (one, two, three, four, six). His accuracy was high for both amodal completed figures, including probe stimuli (28/38 correct) and modally completed figures (29/38 correct), with chance=0.20. The modally completed case (i.e., Kanizsa subjective figures) is of particular importance as there are no shared image parts between training and testing stimuli. We draw several conclusions from these results. First, a surface level completion process is fully operative insofar as Griffin was able to correctly identify shapes that differed considerably from training images. Second, because parrots can generalize from shapes of real objects to drawings where original image contours were clearly absent, the data provide a compelling example of shape invariance, indicating that visual shapes are processed far beyond that of their image description. Third, parrots with a repertoire of multiple vocal responses can be rigorously tested for visual competencies, an option as yet to be tried in other experimental animals.

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“…2007a), their visual fields provide comprehensive visual coverage of the celestial hemisphere and the bill tip lies at the very periphery or outside the visual field (Martin 2007). Parrots (Psittacidae) also have touch‐sensitive bill‐tip organs that are used in the manipulation of objects held within their highly curved bill tips, which in parrots lie at the very periphery of the visual field (Demery et al. 2011).…”

Section: Summary Data On Bill Morphology Eye Position and Foraging mentioning

confidence: 99%

Differences in foraging ecology determine variation in visual fields in ibises and spoonbills (Threskiornithidae)

Martin¹,

Portugal

2011

Ibis

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Variations in visual field topography among birds have been interpreted as adaptations to the specific perceptual challenges posed by the species’ foraging ecology. To test this hypothesis we determined visual field topography in four bird species which have different foraging ecologies but are from the same family: Puna Ibis Plegadis ridgwayi (probes for prey in the soft substrates of marsh habitats), Northern Bald Ibis Geronticus eremita (surface pecks for prey in dry terrestrial habitats), African Spoonbill Platalea alba and Eurasian Spoonbill Platalea leucorodia (bill‐sweeps for prey in shallow turbid waters). All four species employ tactile cues provided by bill‐tip organs for prey detection. We predicted that the visual fields of these species would show general features similar to those found in other birds whose foraging is guided by tactile cues from the bill (i.e. bill falling outside the frontal binocular field and comprehensive visual coverage of the celestial hemisphere). However, the visual fields of all four species showed general features characteristic of birds that take food directly in the bill under visual guidance (i.e. a narrow and vertically long binocular field in which the projection of the bill tip is approximately central and with a blind area above and behind the head). Visual fields of the two spoonbills were very similar but differed from those of the ibises, which also differed between themselves. In the spoonbills, there was a blind area below the bill produced by the enlarged spatulate bill tip. We discuss how these differences in visual fields are related to the perceptual challenges of these birds’ different foraging ecologies, including the detection, identification and ingestion of prey. In particular we suggest that all species need to see binocularly around the bill and between the opened mandibles for the identification of caught prey items and its transport to the back of the mouth. Our findings support the hypothesis that sensory challenges associated with differences in foraging ecology, rather than shared ancestry or the control of locomotion, are the main determinants of variation in visual field topography in birds.

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Vision, touch and object manipulation in Senegal parrots Poicephalus senegalus

Cited by 73 publications

References 41 publications

Evolutionary Specialization of Tactile Perception in Vertebrates

Evolutionary Specialization of Tactile Perception in Vertebrates

Robust representation of shape in a Grey parrot (Psittacus erithacus)

Differences in foraging ecology determine variation in visual fields in ibises and spoonbills (Threskiornithidae)

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