Some observations on the visual optics of kingfishers (Aves, Coraciformes, Alcedinidae)

The authors studied visual optics using opthalmoscopy in six species of coraciform birds, five species from the family Alcedinidae (kingfishers) and one from the family Meropidae (bee-eaters). Retinal ganglion cell isodensity maps were obtained for the sacred kingfisher (Halcyon sancta ) and laughing kookaburra (Dacelo gigas ). Observations provide new insights into the functional significance of the bifoveate visual organization. In particular, the relationship between visual angles suggests on strategy which could be used by kingfishers to maximize their visual capabilities when hunting from perch above the substrate.