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A Role for the Avian Pectén Oculi in Orientation to the Sun?

Pettigrew, John D. (1978) A Role for the Avian Pectén Oculi in Orientation to the Sun? In: Animal Migration, Navigation, and Homing. Proceedings in Life Sciences. Springer , Berlin, pp. 42-54. ISBN 978-3-662-11148-2.

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In addition to its well-accepted nutritive role, I propose a function for the pectén that is a synthesis of the views of Griffin (that it might play a role in migration), Menner (that it casts a shadow), and Barlow (that it blocks intraocular light rays scattered from the sun’s image). New measurements, supported by observations on a scale model, show that the pectén is precisely placed to produce a sharply defined shadow on the field of light scattered within the eye when the sun is imaged on one edge of the retina. The precision of the shadow-casting function becomes evident when one considers the sun’s image as the source of light, rather than direct rays from the sun itself, as Menner had done. The sharp definition of the shadow, its extended linear contour, its proximity to the image of the horizon, and its position within the area of highest retinal resolution would all facilitate precise observation of the sun.

Item Type:Book Section
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Additional Information:© 1978 Springer-Verlag Berlin Heidelberg.
Subject Keywords:Avian pectén; celestial navigation; eye; bird migration
Series Name:Proceedings in Life Sciences
Record Number:CaltechAUTHORS:20200903-130923783
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105244
Deposited By: Tony Diaz
Deposited On:09 Sep 2020 18:07
Last Modified:16 Nov 2021 18:41

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