The visual impediment of cranial ornamentation in male Chrysolophus pheasants

Journal article

Sexually selected traits such as feather ornamentation of male birds can act as an impediment to movement and predator detection. Here we report a previously undocumented example of an impediment derived from a sexually-selected trait; the cranial feather ornamentation in male Chrysolophus pheasants restricting their visual field. Visual fields define the space around an animal from which visual information can be retrieved. Out of the 300 bird species studied to date, there have been no significant differences reported in the visual fields between sexes. Our findings reveal that the cranial feathers of male golden (C. pictus) and Lady Amherst’s (C. amherstiae) pheasants significantly restrict their visual field relative to females and may significantly impede their ability to gather information from the world about them. In summary, males exhibited a blind area that was 137% larger than females, and a significantly reduced area of binocular vision. The two Chrysolophus pheasant species are the first species studied to show a difference in visual fields between sexes; this difference was absent in two closely related species measured, silver pheasants (Lophura nycthemera) and green pheasants (Phasianus versicolor).

Authors: Lamond, A; Potier, S; Fontaine, L; Martin, G; Portugal, S

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Royal Society
• Journal: Biology Letters
• Volume: 25
• Issue: 11
• Article number: 20250405
• Publication date: 2025-11-26
• Acceptance date: 2025-10-15
• DOI: 10.1098/rsbl.2025.0405
• EISSN: 1744-957X
• ISSN: 1744-9561
• Language: English
• Keywords: phasianidae; Lady Amherst’s pheasants; binocularity; galliformes; golden pheasants; moult