Behavioural investigation of polarisation sensitivity in the Japanese quail (Coturnix coturnix japonica) and the European starling(Sturnus vulgaris)

Abstract

SUMMARYMany animals have sensitivity to the e-vector of linearly polarised light,which may assist in visually mediated behaviours such as navigation,signalling and foraging. However, it is still controversial as to whether birds possess polarisation sensitivity. Several studies have found that altering the polarisation patterns of the broad visual field surrounding birds alters their intended migratory orientation. However, electrophysiological tests have failed to elicit evidence for polarisation sensitivity in birds,and the mechanism by which birds might perceive polarised light is unknown. In this experiment, we trained Japanese quail and European starlings to discriminate stimuli differing in their polarisation pattern. Although both quail and starlings were able to discriminate stimuli in which the stimulus sub-components either differed or had the same radiant intensity (the control task), they were unable to discriminate stimuli in which the e-vector orientations of the stimulus sub-components either differed by 90° or had the same angle of polarisation. The birds' successful performance on the control task, but failure to complete the polarisation task, demonstrated that they had all the necessary cognitive abilities to make the discrimination except sensitivity to angle of polarisation. We conclude that quail and starlings are unable to use polarisation cues in this foraging task.

A nocturnal mammal, the greater mouse-eared bat, calibrates a magnetic compass by the sun

“…This is particularly true for the nocturnally adapted eyes of most bats, which consist mostly of rods. Given that the proposed mechanism of detection of polarization in the vertebrate eye is linked to cones (26), it remains unlikely that temperate insectivorous bats detect the polarization pattern at sunset. However, one insectivorous bat species, Eptesicus fuscus, orients toward the postsunset glow on emergence from a roost (27); that is, they are able to perceive it and could thus deduce where the sun sets on a daily basis, provided cloud cover permits.…”

Behavioural and physiological mechanisms of polarized light sensitivity in birds

“…Two early conditioning experiments successfully demonstrated PL sensitivity in homing pigeons [58,59], but other studies reported negative findings [60][61][62][63]. Also, recent discrimination experiments with Japanese quails, Coturnix coturnix japonica, and European starlings, Sturnus vulgaris, were unsuccessful in demonstrating PL sensitivity in birds [64]. There are at least two reasons for the mixed success: (i) reflectance artefacts can be a significant problem in indoor set-ups (cf.…”

“…[61,62]) and (ii) birds may need to be tested in a behavioural context closely simulating natural situations, which might not have been the case in some of the failed studies (e.g. [64]). …”

Avian Visual Pigments: Characteristics, Spectral Tuning, and Evolution

“…Polarization vision has been investigated in teleost fish using both behavioral (e.g., Hawryshyn and Bolger 1990) and electrophysiological paradigms (e.g., Hawryshyn et al 2003), and it appears that only species with photoreceptor mosaics comprising regular, orthogonally orientated double (twin) cones are capable of e-vector discrimination, although the precise mechanism is still unclear (Hawryshyn 2000). However, there is as yet no direct evidence for the ability of birds to detect the e-vector of polarized light (see Coemans et al 1994;Vos Hzn et al 1995;Greenwood et al 2003), and this issue remains controversial.…”