Bare-Part Color in Female Budgerigars Changes from Brown to Structural Blue following Testosterone Treatment but Is Not Strongly Masculinized

Whereas several studies have shown that experimentally increased levels of the androgenic steroid testosterone can affect female behavior, fewer studies have focused on the activational effects of exogenous testosterone on female morphology. With respect to colorful displays in birds, almost exclusively the effects of testosterone manipulation on female carotenoid-based colorations have been studied. Other color types such as structural colors (i.e. UV, blue and violet colors that result from differential light reflection in the nanostructures of the tissue) remain largely unstudied. Here, we investigated the short- and long-term effects of exogenous testosterone on the expression of structural bare-part coloration in female budgerigars, Melopsittacus undulatus. In this parrot species, bare-part coloration is expressed in the cere, a structure over the beak which is brown in females and structural blue in males. We experimentally increased plasma testosterone levels in testosterone-treated females (T-females) compared to controls (C-females) and we performed weekly spectrophotometric measurements of the cere for five weeks after implantation and one measurement after ten weeks. We also estimated the extent to which testosterone masculinized female cere color by comparing the experimental females with untreated males. We found significant effects of testosterone on cere color from week four after implantation onwards. T-females expressed significantly bluer ceres than C-females with higher values for brightness and UV reflectance. T-female cere color, however, remained significantly less blue than in males, while values for brightness and UV reflectance were significantly higher in T-females than in males. Our quantitative results show that exogenous testosterone induces the expression of structural blue color in females but does not strongly masculinize female cere coloration. We provide several potential pathways for the action of testosterone on structural color.     

Effects of nestling condition on UV plumage traits in blue tits: an experimental approach

Intraspecific sexual and social communications are among themost important factors shaping costly color traits in birds.Condition capture models assume that only animals in superiorcondition can develop and maintain a colorful plumage. Althoughthere is good evidence that carotenoid-based components of plumagecolors show condition dependence, the situation is more controversialwith the underlying UV-reflecting structural component. We conducteda brood size manipulation in blue tits (Parus caeruleus) toinvestigate condition-dependent effects on plumage colorationin male and female offspring. Carotenoid chroma and UV reflectanceof the yellow breast plumage showed condition-dependent expressionin male and female fledglings. However, only males that wereraised in reduced broods had higher UV reflectance in the UV/bluetail feathers, whereas female tail coloration did not differbetween treatments. Our data suggest that there is a sex-specificeffect on the blue but not the yellow plumage and that thisis related to differences in the signaling function of bothplumage traits. Although sexual selection may already act onmale nestlings to develop colorful tail feathers for the nextbreeding season, the UV/yellow breast feathers are molted duringthe postjuvenile molt, and their signaling value is likely tobe important for both sexes during the extended postfledglingphase.     

Effect of feather abrasion on structural coloration in male eastern bluebirds Sialia sialis

We used observations of male eastern bluebirds captured twice within a breeding season to test whether changes in structural coloration are related to feather abrasion. Between first and second broods, the UV chroma and brightness of feathers decreased, while hue shifted towards longer wavelengths. Observed changes were greatest for feathers on the head, least for feathers on the rump, and intermediate for feathers on the back. For head feathers, we found a significant correlation between reduction in barb length and UV chroma. Plumage coloration at first capture was correlated with change in UV chroma such that the most ornamented males tended to lose more coloration. Moreover, the magnitude of UV color change was positively related to the number of days between color measurements.To test whether these changes were caused by abrasive properties of the nesting sites, we randomly increased or decreased the abrasiveness of nesting‐box entrances by attaching sand paper or smooth plastic tape. The type of box entrance had no signicant effect on either coloration or barb length change. Our results suggest that feather abrasion is a factor in the seasonal color changes of bluebirds.     

Reproductive correlates of plumage coloration of female Mountain Bluebirds

Many studies have shown that the plumage coloration of male birds can act as an honest signal of quality, indicating benefits that a female could gain from pairing with a specific male. In some species, females also display ornamental plumage, but less is known about the function and potential adaptive significance of female coloration because most research has focused on male coloration. Male Mountain Bluebirds (Sialia currucoides) display full body, ultraviolet (UV)‐blue plumage, whereas female plumage is more subdued, with blue color focused on the rump, wing, and tail. During the 2011 and 2012 breeding seasons (May–July) near Kamloops, BC, Canada, we examined coloration of the rump and tail of female Mountain Bluebirds to determine if their plumage could act as an indicator of direct reproductive benefits (e.g., enhanced parental care or reproductive success) to potential mates. We found no relationship between female plumage coloration and either provisioning rate or fledging success. However, female coloration varied with age, with after‐second‐year (ASY) females having brighter, more UV‐blue tail feathers than second‐year (SY) females. In addition, ASY females with brighter, more UV‐blue tails had larger clutches. We also observed positive assortative mating by tarsus length. Because previous work with other species suggests that female body size may be a good predictor of breeding success, males could potentially benefit from pairing with larger females. However, reproductive success did not vary with female size in our study. Although our evidence that structural plumage coloration of female Mountain Bluebirds is a signal of direct reproductive benefits for males (e.g., higher reproductive success) is limited, our results (i.e., ASY females with brighter tails than SY females, and ASY females with brighter tails having larger clutches) do suggest the potential for sexual selection to act on female coloration.     

The role of ultraviolet-A reflectance and ultraviolet-A induced fluorescence in the appearance of budgerigar plumage: insights from spectrofluorometry and reflectance spectrophotometry

Fluorescence has so far been found in 52 parrot species when illuminated with ultraviolet-A (UVA) 'black' lamps, and two attempts have been made to determine whether such fluorescence plays any role in sexual signalling. However, the contribution of the reflectance versus fluorescence to the total radiance from feathers, even in the most studied species to date (budgerigars), is unclear. Nor has the plumage of this study species been systematically assessed to determine the distribution of fluorescent patches. We therefore used spectrofluorometry to determine which areas of budgerigars fluoresce and the excitation and emission spectra involved; this is the first time that such a technique has been applied to avian plumage. We found that both the yellow crown and (normally hidden) white downy chest feathers exhibit strong UVA-induced fluorescence, with peak emissions at 527 nm and 436 nm, respectively. Conversely, the bright-green chest and dark-blue tail feathers do not fluoresce. When comparing reflectance spectra (400-700 nm) from the yellow crown using illuminants with a proportion of UVA comparable to daylight, and illuminants with all UVA removed, no measurable difference resulting from fluorescence was found. This suggests that under normal daylight the contribution of fluorescence to radiance is probably trivial. Furthermore, these spectra revealed that males had fluorescent crowns with substantially higher reflectance than those of females, in both the UV waveband and at longer wavelengths. Reflectance spectrophotometry was also performed on a number of live wild-type male budgerigars to investigate the chromatic contrast between the different plumage areas. This showed that many plumage regions are highly UV-reflective. Overall our results suggest that rapid surveys using UVA black lamps may overestimate the contribution of fluorescence to plumage coloration, and that any signalling role of fluorescence emissions, at least from the yellow crown of budgerigars, may not be as important as previously thought.     

Ornamental non-carotenoid red feathers of wild burrowing parrots

Bird plumage colors have the potential to indicate individual quality, condition, health, immunocompetence, or the extend of parental care. Color intensity of feathers has been found to correlate with parameters of individual quality, condition, parental care and breeding success. Psittaciformes are well known for their colorful plumage but the significance of parrot coloration is still poorly understood. Red colors are very common in many parrot species. They are produced by at least four non-carotenoid-based pigments (linear polyenal structure). In the present study, we investigated a collection of red abdominal feathers of a marked population of wild Burrowing Parrots Cyanoliseus patagonus in Patagonia, Argentina. The aims of this study were to investigate the ecological significance of the recently described non-carotenoid-based red pigments of Psittaciformes, and the relationships between objectively assessed plumage color and body size, body condition, breeding success and nestling growth in wild Psittaciformes. We found that sexes differed in plumage coloration (sexual dichromatism), that plumage color was a good predictor of female body condition and male size, and we identified the red coloration of the abdominal patch as a signal of individual quality and parental investment.     

Models painted with female-like colors elicited courtship by male common chameleons: Evidence for a courtship releaser

Female common chameleonChamaeleo chamaeleon shows shifts in body colorations during the mating season associated with their sexual stage. The hypothesis that female colorations are used in the inter-sexual communication was tested in the field by using plastic models painted with female-like colors. Three female colorations (Neutral, Receptive and Gravid) and two artificial colorations (White and White plus black spots) as control were used. Twenty models (5 colorations × 4 replicas) were simultaneously located in the field (n=25 experiments), and the reaction by males was scored from 0 (no reaction) to 4 (copulation attempt). A male was observed nearby a model in 59 out of 500 displays. A total of 23 males (38.9%) actively reacted to the model. The response significantly differed among color types, and receptive-like models obtained the strongest response by males. In five cases, males attempted to copulate with the model. The response to receptive coloration by males agrees with previous field studies and suggests that yellow spots with a green background is a courtship releaser.     

Juvenile coloration of Florida Scrub-Jays ( Aphelocoma coerulescens ) is sexually dichromatic and correlated with condition

The Florida Scrub-Jay is a monogamous cooperative breeder in which both males and females display extensive structurally based blue plumage. Juveniles of this species exhibit blue tail and wing feathers that they begin growing as nestlings, and some of these feathers are retained throughout their first year. Although the birds appear to be sexually monochromatic, we assessed whether cryptic dichromatism exists in both the magnitude and pattern of coloration in tail feathers of juvenile Florida Scrub-Jays. We then determined whether variation in plumage coloration is associated with nutritional condition during molt. Tails of juvenile male Florida Scrub-Jays exhibit a greater proportion of UV reflectance than those of females. Mass at age 11 days and ptilochronology of the juvenile tail feathers were used as measures of individual nutritional condition during feather growth, and the latter was found to be positively associated with UV chroma. These data demonstrate that Florida Scrub-Jays are sexually dichromatic and suggest that variation in plumage color may be condition dependent, although we cannot rule out alternative explanations. Juvenile plumage coloration, therefore, has the potential to function as a signal of individual quality in both males and females.     

Comparing the accuracy and precision of three techniques used for estimating missing landmarks when reconstructing fossil hominin crania

In some primate species, pelage colorations at birth contrast with adult colorations. The intensity of natal coats and their phylogenetic distribution is highly variable within primates. Natal coat coloration seems to change to adult coloration in most species when infants become independent from their mothers, but an accepted functional explanation for natal coats is not available. Here we describe pelage coloration change in sexually dichromatic redfronted lemurs (Eulemur fulvus rufus) in Kirindy Forest, and propose a new functional hypothesis for this phenomenon. In this species, infants are born with adult male coloration and female infants subsequently undergo a change in coloration. Using digital pictures and behavioral data collected on eight mother-offspring dyads from birth until the end of the coloration change, we 1) described timing and pattern of pelage developmentin redfronted lemur infants and 2) examined behavioral developmental correlates of the coloration change. The color change took place between 7 and 17 weeks of age and coincided with advanced physical independence; a pattern also found in monochromatic primate species with natal coats. No behavioral differences between male and female infants were found. Hypotheses about the ultimate function of natal coats focusing on enhanced infant care or reduced infanticide risk did not explain the pelage change in redfronted lemurs. The natal pelage pattern in this species may instead serve as sexual mimicry. Accordingly, female infants may mimic males during the most vulnerable developmental phase to avoid sex-specific aggression by adult females in a species with intense female-female aggression and competition.     

Past or present? Relative contributions of developmental and adult conditions to adult immune function and coloration in mallard ducks (<Emphasis Type="Italic">Anas platyrhynchos</Emphasis>)

Developmental conditions affect adult physiological processes and phenotypic traits, including those associated with both survival and reproduction. Carotenoids are molecules that generate sexually attractive coloration, and these pigments are acquired throughout life and can affect antioxidant capacity and immunocompetence of young and old animals. However, few studies have tracked carotenoid status and condition during development and into adulthood to understand how ontogeny affects later-life health and coloration of both males and females. We reared male and female mallard ducks (Anas platyrhynchos) from hatch to adulthood, measured circulating carotenoid titers and body condition (i.e., size-adjusted body mass) throughout development, and assessed adult immune function and integumentary carotenoid-based beak and foot coloration. We found that adult immune function (wing web swelling response to phytohemagglutinin; PHA) in males was positively correlated with body condition during the growth period of development, rather than adult condition, and similarly that both male and female beak coloration was associated with developmental, rather than adult, body condition. We also found associations between coloration and health during adulthood; males with more carotenoid-rich beaks (a sexually attractive feature) tended to have a more robust adult PHA response and a greater antibody response to a novel antigen, while females with less carotenoid-rich beaks had greater antibody responsiveness at adulthood. In addition, male beak color changed over the course of the 24-h PHA test in proportion to the degree of PHA swelling. However, intensity of foot coloration (a trait of unknown sexual significance) was not associated with any condition, carotenoid, or immune metric for males or females. Taken together, our findings implicate key developmental components to the expression of both survival- and reproduction-related traits at adulthood, but that for a dynamic trait like beak color, there are also important adult conditions that can alter signal expression.     

Ornamental plumage coloration and condition are dependent on age in eastern bluebirds Sialia sialis

Male eastern bluebirds Sialia sialis have striking ultraviolet (UV)-blue coloration on their heads, backs, rumps, wings, and tails and bold chestnut coloration on their breasts. These colored areas are ornaments that correlate with pairing date and reproductive effort, and thus probably influence the choice of mates by females. Such ornaments are expected to increase in color with age and body condition. We investigated the effects of age on body condition and the UV-blue and chestnut coloration of males over four years using both cross-sectional (comparing age classes) and longitudinal analyses (following individuals as they age). We found that both the body condition index and brightness of UV-blue rump coloration increased with age, while UV-blue tail plumage coloration increased between yearling and older males, and the chestnut breast coloration decreased in the oldest age class. The proximate mechanisms whereby individuals reliably signal age via rump brightness and tail coloration are probably different. Contour feathers, including rump feathers, are molted at approximately the same time in all age classes and are likely subject to the same production costs in all age classes. In contrast, the molt schedule of the tail and wing feathers differs between individuals of yearling and older age classes, with yearlings retaining wing and tail feathers for several months longer than adults. The relationship between tail color and age was probably, in part, a consequence of yearlings expressing tails that have increased feather wear and accumulation of dirt. In general, UV-blue coloration increased with age while chestnut plumage decreased with age, indicating that older individuals may tradeoff investing energy in structural and melanin ornaments. By assessing overall plumage coloration, female eastern bluebirds could estimate age class when choosing mates.     

Multiple ways to become red: pigment identification in red feathers using spectrometry

Red hues are a challenge in studies on the evolution of bird coloration, as multiple pigments such as carotenoids, pheomelanin, psittacofulvins, porphyrins, turacin, haemoglobin and even exogenous iron-oxides, may confer red colors. Determining the pigment type is paramount and here we investigate the differences in spectrum reflectance for six pigments resulting in red colorations in feathers of different species, with a focus on discriminating among melanins and carotenoids. Pigment chemical identification was obtained from the literature or using High Performance Liquid Chromatography (HPLC) in our laboratory. We have also derived discriminant formulas for identification of the major known types of pigments based on parameters of the reflectance curves obtained with a portable spectrometer. Our results indicate that the reflectance patterns of coloration perceived as red patches widely differ. The distinction between carotenoid- and melanin-based reflectance curves is relatively straightforward: sigmoid versus straight slope. The spectral reflectance curves of feathers containing red psittacofulvins are sigmoid, whereas iron oxide and porphyrin-containing feathers recall pheomelanins in rendering a straight slope. In the case of turacin-based coloration, the spectral shape is unique. For the pigments with enough number of species sampled (i.e., carotenoids, melanins and psittacofulvins) the differences in reflectance shape are important enough to allow separation of carotenoid and melanin derived colorations based on reflectance curves alone.     

Supplemental food increases ornamentation of male nestling Eastern Bluebirds

Although the condition‐dependence and signaling function of ornamental plumage coloration among adult males is well studied, less research has focused on the information content of ornamental coloration among juvenile birds. Eastern Bluebird (Sialia sialis) nestlings grow their nuptial plumage while in the nest and dependent on parents for food, making them an ideal species for studying the development and function of elaborate plumage. Previous research suggests that plumage brightness of Eastern Bluebirds functions, in the juvenile stage, in parent–offspring interactions as a sexually selected trait in adults. Using an experimental approach, we tested the effects of supplemental food on the structural plumage coloration (i.e., tips of primary feathers) of Eastern Bluebird nestlings in Watauga County, North Carolina, during the 2011 breeding season. We provided supplemental mealworms daily to breeding pairs from the onset of incubation through the nestling period, and measured plumage brightness, UV chroma, and mass of nestlings (N = 89 males and 71 females). Male nestlings of supplementally fed parents exhibited brighter plumage. The mass and UV chroma of young bluebirds were not significantly affected by food supplementation. However, the relationship between mass and brightness differed between male nestlings in the control and supplementally fed treatments. Males reared in food‐supplemented territories exhibited a positive relationship between color and mass. Nestlings in control territories, however, exhibited a negative relationship between size and brightness, suggesting that reduced food availability results in a tradeoff between allocating resources toward somatic growth and development of bright plumage. Our results suggest that UV‐blue structural plumage in male juvenile Eastern Bluebirds is at least partially condition‐dependent and may help to explain why plumage color can influence social interactions in Eastern Bluebirds.     

Multiple signaling in a variable environment: expression of song and color traits as a function of ambient sound and light

Many animals communicate using more than one signal, and several hypotheses exist to explain the evolution of multiple signals. However, these hypotheses typically assume static selection pressures, and previous work has not addressed how spatial and temporal environmental variation can shape variation in signaling systems. In particular, environmental variability, such as ambient lighting or noise, may affect efficacy (e.g., detectability/perception by receivers) of signals. To examine how signal expression varies intraspecifically as a function of habitat characteristics, we evaluated relationships between spatial environmental variation and song and plumage color expression in a tropical songbird, the Red‐throated Ant‐tanager (Habia fuscicauda) in Panama. We recorded male ant‐tanager song, plucked feathers to measure coloration, and quantified the acoustic and light environments from each male's territory. In addition, we took several morphological measurements from each male to assess the potential information content of song and plumage color. We found that males with redder and more saturated crown plumage occurred on darker territories, and males that sang shorter and lower frequency songs occurred on noisier territories. We also found that more colorful males tended to sing longer and lower frequency songs. Finally, we found that song and color correlated similarly with male morphology (e.g., tarsus length, body mass). Altogether, these results indicate that spatial variation in the environment is related to male coloration and song, and that males might be optimizing color and song expression for their particular territorial environment.     

Seasonal changes in blue tit crown color: do they signal individual quality?

Plumage coloration is generally perceived as a static traitand therefore not a good indicator of current condition. However,changing of feather colors after molt does occur and may haveimportant implications for signal function and sexual selection.We studied longitudinal changes in blue tit (Parus caeruleus)crown ultraviolet (UV)/blue color, a sexually selected trait,by repeatedly measuring the same individuals between early winterand late spring. Whereas crown UV reflectance (UV chroma andhue) decreased dramatically over time, brightness and saturationdid not show consistent patterns of change. The magnitude ofthe decline in coloration exceeded sexual and age dichromatismin hue and UV chroma, respectively. Hence, seasonal color changescould have strong effects on blue tit sexual signaling. Between-individualvariation in the decline in UV coloration was large and relatedto attributes of male, but not female, quality, such as sizeand condition. Thus, conspecifics could potentially gain informationabout male phenotypic quality by assessing color change overthe year. However, the degree of decline in male UV color didnot affect breeding success because neither the number of within-pairnor the number of extrapair offspring produced correlated withchanges in crown color. Seasonal changes in the expression ofplumage coloration are probably widespread, and maintainingplumage coloration could thus constitute an additional honesty-enforcingmechanism after molt is completed.     

Is Brightest Best? Testing the Hamilton-Zuk Hypothesis in Mandrills

Although many primates exhibit striking coloration, including brightly colored pelage and bare areas of skin, our understanding of the function and evolution of these traits pales in the face of knowledge about color in other taxa. However, recent years have seen an increase in the number of studies of individual variation in primate color and evidence is accumulating that these traits can act as important signals to conspecifics. Mandrills are arguably the most colorful of all primates. Here, we review what we have discovered about the signal function of coloration in male and female mandrills from our long-term studies of a semi-free-ranging colony in Franceville, Gabon and test the predictions of the Hamilton-Zuk hypothesis—that bright coloration is condition dependent, and that only individuals of superior quality will be able to express color fully—in this species. We compare measures of facial coloration in both sexes with parasite load (using fecal analysis over 1 annual cycle), immune status (hematological parameters), neutral genetic diversity (microsatellite heterozygosity), and major histocompatability (MHC) genotype to examine whether red coloration acts as an honest signal of individual quality in mandrills. We found that red coloration was unrelated to parasitism and hematological parameters. Red was also unrelated to genome-wide heterozygosity and MHC diversity, although specific MHC genotypes were significantly related to red. The healthy, provisioned nature of the colony and problems associated with observational, correlational studies restrict interpretation of our data, and it would be premature to draw conclusions as to whether color signals individual quality in mandrills. We conclude with some suggestions for future studies on the signal content of color in mandrills and other primates.     

Informative content of melanin‐based plumage colour in adult Eurasian kestrels

Covariation between melanin‐based colorations and other phenotypic attributes has been rarely measured simultaneously in males and females. Such covariations and mechanisms mediating them have crucial importance determining the signalling function of these coloured ornaments in the two sexes. We examined the role of four melanin‐based coloured plumage patches as indicators of quality in both males and females of the sexually dimorphic and dichromatic Eurasian kestrel Falco tinnunculus. Previous kestrel studies have focused on the size of melanin plumage patches in either males or females as indicators of individual quality. Here, we used spectrophotometric measurements of three plumage patches and the size of another plumage patch to investigate the information content of multiple plumage colour traits in male and female kestrels. We found that females with bright plumage in the head and with high UV chroma in black parts of the rump showed good body condition and innate immunity. In addition, laying date was significantly explained by the intensity of the brown in the head of females. Meanwhile, in males we only found that individuals with greyer rumps showed better innate immunity. Altogether, our results indicate that, irrespective of the mechanism promoting covariation between coloration and individual quality, melanin‐based coloration can inform on individual quality in adult kestrels.     

Fertilization success and UV ornamentation in blue tits Cyanistes caeruleus: correlational and experimental evidence

Cases where less ornamented males are favored through sexualselection are rare among birds. Here we show, based on datafrom 3 consecutive breeding seasons, that male blue tits withless ultraviolet (UV)-ornamented crown feathers sire more offspring.This pattern was mainly driven by the higher success of older,less UV-ornamented males at siring extrapair offspring. Thereason behind this relationship is unclear although we hypothesizethat being less UV-ornamented may enable adult males to intrudeinto nearby territories by mimicking juveniles. To test causality,we experimentally manipulated male crown coloration creating2 groups, one with higher (UV(+) treatment) and one with lowerUV reflectance (UV(–) treatment). Contrary to our expectations,UV(–) males were less likely to sire extrapair offspringthan UV(+) males. The treatment had no effect on the likelihoodof losing paternity in a male's own nest. Because the experimentalevidence does not support the observational data, a direct effectof male crown color on extrapair success cannot be confirmed.However, potential pitfalls of this and other such color manipulationexperiments, like fading of treatment with time and mismatchesbetween behavior and coloration, call for new improved manipulationtechniques and detailed behavioral observations to conclusivelytest for the effect of blue tit crown coloration on male extrapairsuccess.     

Female preferences for aposematic signal components in a polymorphic poison frog

Aposematic signals may be subject to conflicting selective pressures from predators and conspecifics. We studied female preferences for different components of aposematic coloration in the polymorphic poison frog Oophaga pumilio across several phenotypically distinct populations. This frog shows striking diversity in color and pattern between geographically isolated populations in western Panama. Results indicate that male dorsal color is the most important determiner of female preferences. We did not find consistent evidence for effects of other signal components, such as spotting pattern or ventral color. Females in two populations showed assortative preferences mediated by male dorsal coloration. In a third population we found incomplete color-assortative preference behavior, with females exhibiting strong discrimination toward one novel color but not another. These results hint at a possible interaction between sexual and natural selection: female tolerance of unfamiliar coloration patterns could facilitate the establishment of novel phenotypes that are favored by other selective pressures (e.g., predator biases). Furthermore, our study suggests that specific components of the aposematic signal (i.e., dorsal color, ventral color, and spotting pattern) are affected differently by natural and sexual selection.     

Plumage maintenance affects ultraviolet colour and female preference in the budgerigar

Elaborate or colourful feathers are important traits in female-mate choice in birds but little attention has been given to the potential costs of maintaining these traits in good condition via preening behaviour. While preening is known to be an important component of plumage maintenance, it has received little attention with respect to colouration. We investigated whether preening can influence plumage reflectance and whether females show a preference for plumage cleanliness in captive-bred, wild-type budgerigars, Melopsittacus undulatus. To do this, we compared the spectral colour of birds that were allowed to preen their plumage and individuals that were prevented from preening. The plumage of birds that were prevented from preening showed a significant lower reflectance in the UV range (300-400 nm). Subsequently, we measured females’ preferences for preened and unpreened males using a two-choice test. In a second experiment we allowed females to choose between an unpreened male and a male smeared with UV-absorbing chemicals (UV-blocked male). The proportion of time that females stayed near preened males was statistically higher than for unpreened males, but females spent similar amounts of time with unpreened males and UV-blocked males. These results are consistent with the idea that female budgerigars are able to discriminate between preened and unpreened males, and that UV colours, mediated by preening, can convey information about a bird's current condition.