Studies on UV reflection in feathers of some 1000 bird species: are UV peaks in feathers correlated with violet‐sensitive and ultraviolet‐sensitive cones?

Abstract

Nine hundred and sixty-eight bird species, covering all orders, were studied in search of distinctive ultraviolet reflections. All species in the following orders were completely surveyed: Struthioniformes, Tinamiformes, Craciformes, Turniciformes, Galbuliformes, Upupiformes, Coliiformes, Apodiformes and Musophagiformes. The coloured plumage regions in particular exhibited high proportions of UV-reflecting feathers. Bird orders with species which are believed to possess VS (violet-sensitive) cone types mostly had their UV maxima between 380 and 399 nm while orders with species which are assumed to have UVS (ultravioletsensitive) cone types contained significantly species which had their UV maxima between 300 and 379 nm. With an emphasis on non-passerine birds the present study provides evidence that birds of many more groups may see UV light than have been studied to date. Ecological aspects related to UV reflection and perception, as well as sexual dimorphism visible only in the UV, are discussed.

Ultraviolet-sensitive vision in long-lived birds

“…The highest percentage (more than 10%) of UV reflectance is usually found in blue and white feathers, although feathers reflecting predominantly at longer wavelengths can have a biologically significant UV reflectance [28,47 -49]. Parrots have the highest percentage of UV reflectance, especially in plumage patches when compared with all other avian orders, and in a survey of 143 species, all but three were shown to possess a considerable amount of UV-reflecting plumage [48].…”

“…A better understanding of the visual ecology of these birds will be essential in determining how UV sensitivity is employed. UV-reflecting plumages are found ubiquitously across all avian lineages, including parrots, suggesting that UV reflectance is an ancestral characteristic of the avian order [27,47,48]. The highest percentage (more than 10%) of UV reflectance is usually found in blue and white feathers, although feathers reflecting predominantly at longer wavelengths can have a biologically significant UV reflectance [28,47 -49].…”

Candidate genes for colour and vision exhibit signals of selection across the pied flycatcher (Ficedula hypoleuca) breeding range

“…Whether variation in photic conditions, and UV radiation in particular, could be a selective force resulting in divergent selection in pied flycatchers, however, remains to be investigated. An examination of several other bird species has demonstrated that cone type and plumage UV maxima (that is, reflection and perception) tend to be associated (Mullen and Pohland, 2008). A useful follow-up study to address this issue would be to sequence the parts of the SWS opsin genes, which confer spectral sensitivity (for example, Ö deen et al, 2009), to examine whether the different populations have different mutations at these sites.…”

Visual pigments in a palaeognath bird, the emuDromaius novaehollandiae: implications for spectral sensitivity and the origin of ultraviolet vision

“…Generally, their plumage has a low spectral reflectance in the UV region of the spectrum, with no notable peaks compared to other spectral regions [63], and at least some of the structural and optical properties of the mostly greyish-brown plumage in the emu may be adapted for thermoregulation [64] rather than intraspecific communication. Adult emus have patches of blue skin on their head and neck that are (subjectively to humans) 'darker' in females than males and absent from juveniles [65], which may be important in sexual selection.…”