The scaling of eye size in adult birds: relationship to brain, head and body sizes.
Birds' eyes seem often to be about as large as head size allows and brain size is taken here as a measure of the ill-defined space that is available to accommodate them. In four data sets for non-passerines eye size relates more strongly to brain size than to body mass and most non-passerine data are consistent with eye:brain (or eye:head-space) isometry. Eye:body allometry thus seems to follow from a negative head-space:body allometry. In passerines the eye:brain size correlations seem to be secondary to strong eye:body, brain:body, and perhaps therefore head-space:body correlations, a difference attributed to the passerines' greater anatomical uniformity.
Burton
Richard F
RF
Faculty of Biomedical and Life Sciences, University of Glasgow, Thomson Building, Glasgow G12 8QQ, UK. R.F.Burton@bio.gla.ac.uk