Anatomical specializations for nocturnality in a critically endangered parrot, the Kakapo (Strigops habroptilus)

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dc.contributor.authorCorfield, Jeremy R.
dc.contributor.authorGsell, Anna C.
dc.contributor.authorBrunton, Dianne
dc.contributor.authorHeesy, Christopher P.
dc.contributor.authorHall, Margaret I.
dc.contributor.authorAcosta, Monica L.
dc.contributor.authorIwaniuk, Andrew N.
dc.date.accessioned2016-11-10T21:37:57Z
dc.date.available2016-11-10T21:37:57Z
dc.date.issued2011
dc.descriptionSherpa Romeo green journal: open accessen_US
dc.description.abstractThe shift from a diurnal to nocturnal lifestyle in vertebrates is generally associated with either enhanced visual sensitivity or a decreased reliance on vision. Within birds, most studies have focused on differences in the visual system across all birds with respect to nocturnality-diurnality. The critically endangered Kakapo (Strigops habroptilus), a parrot endemic to New Zealand, is an example of a species that has evolved a nocturnal lifestyle in an otherwise diurnal lineage, but nothing is known about its’ visual system. Here, we provide a detailed morphological analysis of the orbits, brain, eye, and retina of the Kakapo and comparisons with other birds. Morphometric analyses revealed that the Kakapo’s orbits are significantly more convergent than other parrots, suggesting an increased binocular overlap in the visual field. The Kakapo exhibits an eye shape that is consistent with other nocturnal birds, including owls and nightjars, but is also within the range of the diurnal parrots. With respect to the brain, the Kakapo has a significantly smaller optic nerve and tectofugal visual pathway. Specifically, the optic tectum, nucleus rotundus and entopallium were significantly reduced in relative size compared to other parrots. There was no apparent reduction to the thalamofugal visual pathway. Finally, the retinal morphology of the Kakapo is similar to that of both diurnal and nocturnal birds, suggesting a retina that is specialised for a crepuscular niche. Overall, this suggests that the Kakapo has enhanced light sensitivity, poor visual acuity and a larger binocular field than other parrots. We conclude that the Kakapo possesses a visual system unlike that of either strictly nocturnal or diurnal birds and therefore does not adhere to the traditional view of the evolution of nocturnality in birds.en_US
dc.description.peer-reviewYesen_US
dc.identifier.citationCorfield, J. R., Gsell, A. C., Brunton, D., Heesy, C. P., Hall, M. I., Acosta, M. L., & Iwaniuk, A. N. (2011). Anatomical specializations for nocturnality in a critically endangered parrot, the Kakapo (Strigops habroptilus). PLoS ONE, 6(8), e22945. doi:10.1371/journal.pone.0022945en_US
dc.identifier.urihttps://hdl.handle.net/10133/4662
dc.language.isoen_CAen_US
dc.publisherPublic Library of Scienceen_US
dc.publisher.departmentDepartment of Neuroscienceen_US
dc.publisher.facultyArts and Scienceen_US
dc.publisher.institutionUniversity of Lethbridgeen_US
dc.publisher.institutionMassey Universityen_US
dc.publisher.institutionMidwestern Universityen_US
dc.publisher.institutionUniversity of Aucklanden_US
dc.subjectKakapoen_US
dc.subjectStrigops habroptilusen_US
dc.subjectNocturnalen_US
dc.subjectDiurnalen_US
dc.subjectVisual systemen_US
dc.subjectVisual pathwayen_US
dc.subjectMorphological analysisen_US
dc.titleAnatomical specializations for nocturnality in a critically endangered parrot, the Kakapo (Strigops habroptilus)en_US
dc.typeArticleen_US
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