title: Visual acuity in an opportunistic raptor, the chimango caracara (Milvago chimango).
abstract: Raptors are always considered to have an extraordinary resolving power of their eyes (high visual acuity). Nevertheless, raptors differ in their diet and foraging tactics, which could lead to large differences in visual acuity. The visual acuity of an opportunist bird of prey, the Chimango caracara (Mivalgo chimango) was estimated by operant conditioning. Three birds were trained to discriminate two stimuli, a positive grey uniform pattern and a negative grating pattern stimulus. The visual acuity range from 15.08 to 39.83 cycles/degrees. When compared to other birds, they have a higher visual acuity than non-raptorial birds, but they have the lowest visual acuity found in bird of prey so far. We discuss this result in the context of the ecology of the bird, with special focus on it is foraging tactic.
authors.affiliation: CEFE UMR 5175, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, EPHE, 1919 route de Mende, 34293 Montpellier cedex 5, France. Electronic address: simon.POTIER@cefe.cnrs.fr.
authors.forename: Simon
authors.initials: S
authors.lastname: Potier
authors.affiliation: CEFE UMR 5175, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, EPHE, 1919 route de Mende, 34293 Montpellier cedex 5, France.
authors.forename: Francesco
authors.initials: F
authors.lastname: Bonadonna
authors.affiliation: Department of Biology, Lund University, Sölvegatan 35, S-22362 Lund, Sweden.
authors.forename: Almut
authors.initials: A
authors.lastname: Kelber
authors.affiliation: CEFE UMR 5175, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, EPHE, 1919 route de Mende, 34293 Montpellier cedex 5, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Duriez
mesh_terms: D000818:Animals; D003216:Conditioning, Operant / Q000502:physiology; D005123:Eye / Q000033:anatomy & histology; D046093:Falconiformes / Q000502:physiology*; D013045:Species Specificity; D014792:Visual Acuity / Q000502:physiology*
keywords: Chimango caracara; Operant conditioning; Opportunistic raptor; Visual acuity