Journal of Comparative Physiology A

, Volume 192, Issue 5, pp 523–534

Spatial contrast sensitivity of birds

Original Paper

DOI: 10.1007/s00359-005-0090-5

Cite this article as:
Ghim, M.M. & Hodos, W. J Comp Physiol A (2006) 192: 523. doi:10.1007/s00359-005-0090-5
  • 406 Downloads

Abstract

Contrast sensitivity (CS) is the ability of the observer to discriminate between adjacent stimuli on the basis of their differences in relative luminosity (contrast) rather than their absolute luminances. In previous studies, using a narrow range of species, birds have been reported to have low contrast detection thresholds relative to mammals and fishes. This was an unexpected finding because birds had been traditionally reported to have excellent visual acuity and color vision. This study reports CS in six species of birds that represent a range of visual adaptations to varying environments. The species studied were American kestrels (Falco sparverius), barn owls (Tyto alba), Japanese quail (Coturnix coturnix japonica), white Carneaux pigeons (Columba livia), starlings (Sturnus vulgaris), and red-bellied woodpeckers (Melanerpes carolinus). Contrast sensitivity functions (CSFs) were obtained from these birds using the pattern electroretinogram and compared with CSFs from the literature when possible. All of these species exhibited low CS relative to humans and most mammals, which suggests that low CS is a general characteristic of birds. Their low maximum CS may represent a trade-off of contrast detection for some other ecologically vital capacity such as UV detection or other aspects of their unique color vision.

Keywords

Contrast sensitivityRefractive statePattern electroretinogramSpatial visionBirds

Abbreviations

c

Cycle

CRF(s)

Contrast–response function(s)

CRT

Cathode-ray tube

CS

Contrast sensitivity

CSF(s)

Contrast sensitivity function(s)

D

Diopter

deg

Degree

Hz

Hertz

IACUC

Institutional animal care and use committee

MTF(s)

Modulation transfer function(s)

PERG(s)

Pattern electroretinogram(s)

SF

Spatial frequency

UV

Ultraviolet

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  1. 1.Department of PsychologyUniversity of Maryland at College ParkCollege ParkUSA