Coloration In Birds Research Articles

The phylogeography of red and yellow coppersmith barbets (Aves: Megalaima haemacephala)

Understanding the evolution of color in birds is important because it is used for both inter- and intra-specific communication and is often linked to other important traits including life history, behavior, immunology and mate choice. The coppersmith barbet (Megalaima haemacephala) is widely distributed across southern Asia and many islands of the Sunda shelf and the Philippines. It occurs in two well-differentiated and completely allopatric color morphs, a red- and a yellow-headed form. We constructed a phylogeny of coppersmith barbets from both color morphs and from across their range using sequences from two mitochondrial and one nuclear loci. Strong geographical patterns were found, in which India and Sri Lanka, the Philippines and mainland tropical east Asia (TE Asia), and the islands on the Sunda shelf (Sundaland) each formed a divergent group. The red birds formed two clades within the diversity of yellow animals. Major clades were dated using a molecular clock calibrated on a larger phylogeny. The phylogeographic patterns suggest that the species likely originated in TE Asia/ Sundaland and then colonized the Philippines from the south in the mid-Pleistocene, via a now extinct population on Borneo. More recently, coppersmith barbets colonized India and Sri Lanka, also from TE Asia/ Sundaland. Coppersmith barbets were also likely distributed in the past on the Malay Peninsula, but went extinct there too. The population that now inhabits this region derives from a natural recolonization of yellow morph birds about 80 years ago. The red morph evolved at least twice independently from the yellow morph in the late Pleistocene, suggesting that this change does not require very many mutational steps, and thus can arise repeatedly.

Color expression in experimentally regrown feathers of an overwintering migratory bird: implications for signaling and seasonal interactions.

Plumage coloration in birds plays a critical role in communication and can be under selection throughout the annual cycle as a sexual and social signal. However, for migratory birds, little is known about the acquisition and maintenance of colorful plumage during the nonbreeding period. Winter habitat could influence the quality of colorful plumage, ultimately carrying over to influence sexual selection and social interactions during the breeding period. In addition to the annual growth of colorful feathers, feather loss from agonistic interactions or predator avoidance could require birds to replace colorful feathers in winter or experience plumage degradation. We hypothesized that conditions on the wintering grounds of migratory birds influence the quality of colorful plumage. We predicted that the quality of American redstart (Setophaga ruticilla) tail feathers regrown after experimental removal in Jamaica, West Indies, would be positively associated with habitat quality, body condition, and testosterone. Both yearling (SY) and adult (ASY) males regrew feathers with lower red chroma, suggesting reduced carotenoid content. While we did not observe a change in hue in ASY males, SY males shifted from yellow to orange plumage resembling experimentally regrown ASY feathers. We did not observe any effects of habitat, testosterone, or mass change. Our results demonstrate that redstarts are limited in their ability to adequately replace colorful plumage, regardless of habitat, in winter. Thus, feather loss on the nonbreeding grounds can affect social signals, potentially negatively carrying over to the breeding period.

On Genius & Happenstance in Scientific Discovery

On June 18, 1858, Charles Darwin, a noted and widely respected British naturalist, received another letter from a fellow naturalist collecting specimens halfway around the world, in the Malay archipelago. The correspondent asked Darwin to review a manuscript and forward it on to a colleague. A conventional professional courtesy. Almost routine. But Darwin read the enclosed essay with dismay. It was, as he confided to a friend, a nearly perfect abstract of his own thoughts, which he had committed to paper some two decades earlier, but never published. The writer was Alfred Russel Wallace. Like Darwin, he had discovered the role of variation and selection in the origin of new species. Such independent discoveries invite reflection on the role of creativity in science. Why does one person, and not another, make a significant discovery? We tend to regard momentous insights as acts of genius, an inherent property of the person. But when two scientists make the same discovery, is the genius shared or does the coincidence reflect an inevitability? After grasping Darwin’s central idea, Thomas Huxley later recalled thinking, “How extremely stupid not to have thought of that!” (Huxley, 1887, p. 197). He chastised himself and colleagues: “we reproached ourselves with dullness for being perplexed with such an inquiry.” Of course, that is the nature of virtually every discovery. It seems perfectly obvious once someone has already articulated it. The prospective view is far less clear. And for that very reason, Huxley’s clever remark was full of irony: namely, we owe the discovery of natural selection to exceptional insight. On Huxley’s principle, generally endorsed I think, Darwin and Wallace are each honored for their genius. “Great minds think alike,” we often hear (Carroll, 2009). Here I wish to challenge the conventional view of genius and discovery, this month’s …

Morphological Studies on the Adrenal Gland of Kuttanad Ducks (Anas platyrhynchos domesticus) During Post Hatch Period

Post hatch development of adrenal gland in Kuttanad ducks was studied using 78 female birds ranging from day-old to 24 weeks of age. Adrenal glands were collected from six birds in each age group at fortnightly intervals. The glands were too small in the day-old ducklings and were located in the body cavity ventral to the anterior pole of cephalic lobe of kidney just posterior to the lungs. The left adrenal was closely related to the ovary in all the age groups and was deeply embedded in the ovary occasionally. In day-old ducklings, both the glands were globular in shape but later the right adrenal became roughly pyramidal with the apex pointing caudally, while the left one was elongated and flattened dorsoventrally. The glands were cream or yellow in colour in younger birds, but later the colour changed to brown. The left adrenal gland was slightly heavier than the right in all the age groups. The mean weight of the gland increased progressively from day-old to 12 weeks of age and thereafter it showed an irregular pattern up to sexual maturity. The absolute mean adrenal weight in Kuttanad duck was 6.27 mg per 100 g body weight at 12th week of age and reached a level of 5.31 mg at 16th week (at the beginning of egg laying) and again increased to 9.60 mg per 100 g body weight at 24 weeks of age. The combined adrenal weight was more correlated with the age than with the body weight. The proportionate mean weight of the adrenal glands to the body weight showed a decreasing trend

Thin Film and Multilayer Optics Cause Structural Colors of Many Insects and Birds

Structural effects contribute to the coloration of many animals. Whereas extremely complex structures have evolved, often coloration is due to the most simple structure, namely a thin film. Here we present a number of examples where thin film optics plays a prominent role, namely in insect wings and bird feathers. Most butterfly wing scales have a lower lamina that prominently determines the color. Damselfly wings with protrusions have reduced thin film reflections. A limited stack of multilayers features also distinct thin film properties, as is shown for feather barbules of the bird of paradise, Lawes’ parotia. A simple method to derive the thickness of the wing structures is described.

Foraging for carotenoids: do colorful male hihi target carotenoid-rich foods in the wild?

Dietary access to carotenoids is expected to determine the strength of carotenoid-based signal expression and potentially to maintain signal honesty. Species that display carotenoid-based yellow, orange, or red plumage are therefore expected to forage selectively for carotenoid-rich foods when they are depositing these pigments during molt, but whether they actually do so is unknown. We set out to address this in the hihi (Notiomystis cincta), a New Zealand passerine where males, but not females, display yellow carotenoid-based plumage. We measured circulating carotenoid concentrations in male and female hihi during breeding and molt, determined the nutritional content of common foods in the hihi diet, and conducted feeding observations of male and female hihi during molt. We found that although male and female hihi do not differ significantly in plasma carotenoid concentration, male hihi have a greater proportion of carotenoid-rich foods in their diet than do females. This is a consequence of a greater fruit and lower invertebrate intake than females and an avoidance of low-carotenoid content fruit. By combining behavioral observations with quantification of circulating carotenoids, we present evidence that colorful birds forage to maximize carotenoid intake, a conclusion we would not have drawn had we examined plasma carotenoids alone.

The contribution of single and double cones to spectral sensitivity in budgerigars during changing light conditions

Bird colour vision is mediated by single cones, while double cones and rods mediate luminance vision in bright and dim light, respectively. In daylight conditions, birds use colour vision to discriminate large objects such as fruit and plumage patches, and luminance vision to detect fine spatial detail and motion. However, decreasing light intensity favours achromatic mechanisms and eventually, in dim light, luminance vision outperforms colour vision in all visual tasks. We have used behavioural tests in budgerigars (Melopsittacus undulatus) to investigate how single cones, double cones and rods contribute to spectral sensitivity for large (3.4°) static monochromatic stimuli at light intensities ranging from 0.08 to 63.5 cd/m². We found no influences of rods at any intensity level. Single cones dominate the spectral sensitivity function at intensities above 1.1 cd/m², as predicted by a receptor noise-limited colour discrimination model. Below 1.1 cd/m², spectral sensitivity is lower than expected at all wavelengths except 575 nm, which corresponds to double cone function. We suggest that luminance vision mediated by double cones restores visual sensitivity when single cone sensitivity quickly decreases at light intensities close to the absolute threshold of colour vision.

Melanin‐based coloration covaries with fluctuating asymmetry, nutritional state and physiological stress response in common snipe

Adaptative significance of melanin‐based coloration in birds remains poorly recognized. It has been suggested that genes responsible for melanin synthesis may have pleiotropic effect on several physiological and behavioural functions, including immune defence. For this reason, we could expect that the expression of melanin‐based plumage coloration should covary with different condition‐related phenotypic traits via regulation of pathogen/parasite resistance. The aim of this study was to test this hypothesis in common snipe Gallinago gallinago, a species that exhibits conspicuous variation in the black eumelanism of underwing plumage. The study was conducted in central Poland, where common snipe were captured during autumn migration. We found that after accounting for the effects of age, sex and date of capture, underwing coloration correlated with nutritional state of snipes, as more extensively melanised individuals had higher plasma concentrations of triglycerides, total protein and albumin. Dark underwing coloration was also associated with lower heterophil/lymphocyte (H/L) ratio, suggesting better resistance of eumelanic individuals to physiological stress. Finally, adult males with darker underwings had lower asymmetry in wing shape (wingtip convexity), which indicated their higher developmental stability. In conclusion, melanin‐based coloration may be considered an honest indicator of phenotypic quality in common snipe.

Association of Tyrosinase (TYR) and Tyrosinase-related Protein 1 (TYRP1) with Melanic Plumage Color in Korean Quails (Coturnix coturnix).

TYR (Tyrosinase) and TYRP1 (Tyrosinase-related protein 1) play crucial roles in determining the coat color of birds. In this paper, we aimed to characterize the relationship of TYR and TYRP1 genes with plumage colors in Korean quails. The SNPs were searched by cDNA sequencing and PCR-SSCP in three plumage color Korean quails (maroon, white and black plumage). Two SNPs (367T→C and 1153C→T) were found in the coding region of TYRP1 gene, but had no significant association with plumage phenotype in Korean quails. The expression of TYR was higher in black plumage quails than that in maroon plumage quails. In contrast, the expression of TYRP1 was lower in black plumage quails than that in maroon plumage quails. This study suggested that the melanic plumage color in Korean quails may be associated with either increased production of TYR or decreased production of TYRP1.

How hollow melanosomes affect iridescent colour production in birds

Developmental constraints and trade-offs can limit diversity, but organisms have repeatedly evolved morphological innovations that overcome these limits by expanding the range and functionality of traits. Iridescent colours in birds are commonly produced by melanin-containing organelles (melanosomes) organized into nanostructured arrays within feather barbules. Variation in array type (e.g. multilayers and photonic crystals, PCs) is known to have remarkable effects on plumage colour, but the optical consequences of variation in melanosome shape remain poorly understood. Here, we used a combination of spectrophotometric, experimental and theoretical methods to test how melanosome hollowness--a morphological innovation largely restricted to birds--affects feather colour. Optical analyses of hexagonal close-packed arrays of hollow melanosomes in two species, wild turkeys (Meleagris gallopavo) and violet-backed starlings (Cinnyricinclus leucogaster), indicated that they function as two-dimensional PCs. Incorporation of a larger dataset and optical modelling showed that, compared with solid melanosomes, hollow melanosomes allow birds to produce distinct colours with the same energetically favourable, close-packed configurations. These data suggest that a morphological novelty has, at least in part, allowed birds to achieve their vast morphological and colour diversity.

Ultraviolet reflectance influences female preference for colourful males in the European serin

Avian plumage colouration is one of the most impressive displays in nature and is frequently used as sexual signal. There is now considerable evidence that females consistently prefer males with the most elaborated colour displays. Bird colour vision expands into the ultraviolet (UV) range, which prompted several studies to test the importance of UV in mate choice, revealing that females are affected by the UV light component. These studies were mostly performed on structural plumage, whereas carotenoid-based plumage was rarely considered, although it also has a typical reflection peak in the UV. Our study tested the female choice over male yellow colouration, and whether it is influenced by UV removal, in the European serin (Serinus serinus), a sexually dichromatic cardueline finch, with males showing a conspicuous carotenoid-based yellow plumage. We shows that females preferred yellower males and that male attractiveness was lost when the UV colouration was blocked, with either of the UV-blocking techniques used. The results of our study indicate that the UV component of carotenoid colouration is important in the female mate assessment in serins and highlights the importance of considering colour perception in avian mate choice.

Occurrence of hybrids between Momotus momota and Baryphthengus ruficapillus (Momotidae) in central Brazil

Abstract We describe a hybrid between the Amazonian Motmot (Momotus momota) and the Rufous-capped Motmot (Baryphthengus ruficapillus), collected in northern Goias, Brazil. In some characters (e.g., shape of the tail and facial mask) the hybrid is similar to B. ruficapillus, in others (e.g., measures and amount of blue in the plumage) it is intermediate between the two parents, and in others (e.g., color of the underparts) it is unlike any of them. Photographs document the occurrence of hybrids in two additional localities in Goias. Complexity of the genetic control of plumage color in birds may explain the hybrid's characters, and rarity of B. ruficapillus may be a factor leading to hybridization between these species. This is the first known case of intergeneric hybridization in the Coraciiformes.

토종 '우리맛닭' 부계 및 실용계에서 MC1R 유전자 변이 및 모색과의 연관성 분석

Department of Animal Science and Biotechnology, Chungnam National University, Daejeon 305-764, KoreaABSTRACT There are several loci controlling the feather color of birds, of which one of the most studied is Extended black (E) encoding the melanocortin 1-receptor (MC1R). Mutations in this gene affect the relative distribution of eumelanin, phaeomelanin. The association of feather color and sequence polymorphism in the melanocortin 1-receptor (MC1R) gene was investigated using Korean native chicken H breed (H_PL) and ‘Woorimatdag’ commercial chickens (Woorimatdag_CC). In order to correlate gene mutation to Korean native chicken feather color, single nucleotide polymorphism (SNP) from MC1R gene sequence were investigated. A total of 307 birds from H_PL and Woorimatdag_CC were used. H_PL have black, black-brown feather color and Woorimatdag_CC have black with brown spots or brown with black spots. There are 6 SNPs in MC1R gene, locus T69C, C212T, A274G, G376A, G636A, T637C. 3 SNPs are nonsynonymous that change amino acid. But it is difficult to find correlation of feather color and polymorphisms. It will be needed to increase the population of Korean native chicken H breed and correlation analysis of genetic variation with feather colors.(Key words : Korean Native Chickens, feather color, MC1R, SNP)

Parents, predators, parasites, and the evolution of eggshell colour in open nesting birds

The colourful surface of birds’ eggshells varies dramatically between species, but the selective pressures driving this variation remain poorly understood. We used a large comparative dataset to test several hypotheses proposed to explain the evolution of eggshell colouration. We tested the hypothesis that predation pressure might select for cryptic eggshells by examining the relationship between predation rate and egg colouration. We found that predation rates were positively related to eggshell brightness. The blackmail hypothesis suggests that females lay colourful eggshells to coerce males into providing additional care during incubation to keep colourful eggs covered. According to this hypothesis, conspicuous eggs should be found in situations with high risk of visual detection from predators or brood parasites. In support of this hypothesis, proportional blue-green chroma was positively related to parasitism risk, and eggs with higher proportional blue-green chroma or higher ultraviolet chroma received higher combined parental nest attendance during the incubation period. The sexual signalling hypothesis states that blue-green colour indicates female quality; however, we did not find that blue-green eggshell colour was greater in species where males participate in any form of parental care, and relative male provisioning was unrelated to blue-green eggshell chroma. We found some support for the hypothesis that brood parasitism may select for high inter-clutch variation in eggshell colour to facilitate egg recognition. In our dataset, parasitism risk was negatively related to inter-clutch repeatability of blue-green chroma. Our study highlights the diversity of selection pressures acting on the evolution of eggshell colour in birds and provides suggestions for novel areas of future key research direction.

Variation in Assemblages of Feather Bacteria in Relation to Plumage Color in Female Great Tits

Abstract. Microorganisms are known to play an important role in shaping the life histories of animals. Recent studies have proposed that the coloration of birds' plumage could reflect individual quality through associations with feather-degrading bacteria. However, few studies have explored such relationships. We studied breeding female Great Tits (Parus major) during nest building and chick rearing to explore associations between bacteria inhabiting their yellow chest feathers and feather coloration. Specifically, we used flow cytometry and ribosomal intergenic spacer analysis (RISA), respectively, to study the densities of all free-living and attached bacteria and the phylotypic richness of feather-degrading bacterial assemblages. We used chroma (color saturation) as a measure of feather coloration. During chick rearing but not during nest building, the female's chroma was negatively related to the phylotypic richness of feather-degrading bacteria. Also, a seasonal change in the density of attached bact...

Eggshell colour is more strongly affected by maternal identity than by dietary antioxidants in a captive poultry system

Summary1.Biologists have long puzzled over the apparent conspicuousness of blue‐green eggshell coloration in birds. One candidate explanation is the ‘sexual signalling hypothesis’ that the blue‐green colour of eggshells can reveal an intrinsic aspect of females' physiological quality, with only high‐quality females having sufficient antioxidant capacity to pigment their eggs with large amounts of biliverdin. Subsequent work has argued instead that eggshell colour might signal condition‐dependent traits based on diet.2.Using Araucana chickens that lay blue‐green eggs, we explored (i) whether high levels of dietary antioxidants yield eggshells with greater blue‐green reflectance, (ii) whether females differ from one another in eggshell coloration despite standardized environments, diets and rearing conditions, and (iii) the relative strength with which diet vs. female identity affects eggshell coloration.3.We reared birds to maturity and then placed them on either a high‐ or low‐antioxidant diet, differing fourfold in Vitamin E acetate and Vitamin A retinol. After 8 weeks, the treatments were reversed, such that females laid eggs on both diets in an order‐balanced design. We measured the reflectance spectra of 545 eggs from 25 females.4.Diet had a very limited effect on eggshell spectral reflectance, but individual females differed strongly and consistently from one another, despite having been reared under uniform conditions. However, predictions from avian visual modelling suggest that most of the egg colour differences between females, and nearly all of the differences between diets, are unlikely to be visually discriminable.5.Our data suggest that eggshell reflectance spectra may carry information on intrinsic properties of the female that laid the eggs, but the utility of this coloration as a signal to conspecifics in this species may be limited by the sensitivity of a receiver to detect it.

THE NOT-SO-PLAIN DUET OF THE PLAIN-TAILED WREN

![][1] Among the beautiful, colourful birds inhabiting the Andean mountains of Ecuador, plain-tailed wrens seem rather underwhelming; little drab-looking birds hopping around bamboo thickets looking for the insects that will be their next meal. However, despite their dull appearance,

A photonic heterostructure produces diverse iridescent colours in duck wing patches

The colours of birds are diverse but limited relative to the colours they can perceive. This mismatch may be partially caused by the properties of their colour-production mechanisms. Aside from pigments, several classes of highly ordered nanostructures (thin films, amorphous three-dimensional arrays) can produce a range of colours. However, the variability of any single nanostructural class has rarely been explored. Dabbling ducks are a speciose clade with substantial interspecific variation in the iridescent coloration of their wing patches (specula). Here, we use electron microscopy, spectrophotometry, polarization and refractive index-matching experiments, and optical modelling to examine these colours. We show that, in all species examined, speculum colour is produced by a photonic heterostructure consisting of both a single thin-film of keratin and a two-dimensional hexagonal lattice of melanosomes in feather barbules. Although the range of possible variations of this heterostructure is theoretically broad, only relatively close-packed, energetically stable variants producing more saturated colours were observed, suggesting that ducks are either physically constrained to these configurations or are under selection for the colours that they produce. These data thus reveal a previously undescribed biophotonic structure and suggest that both physical variability and constraints within single nanostructural classes may help explain the broader patterns of colour across Aves.

Androgen receptor driven transcription in molecular apocrine breast cancer is mediated by FoxA1

Corrigendum21 March 2012free access Androgen receptor driven transcription in molecular apocrine breast cancer is mediated by FoxA1 Jessica L L Robinson Jessica L L Robinson Search for more papers by this author Stewart MacArthur Stewart MacArthur Search for more papers by this author Caryn S Ross-Innes Caryn S Ross-Innes Search for more papers by this author Wayne D Tilley Wayne D Tilley Search for more papers by this author David E Neal David E Neal Search for more papers by this author Ian G Mills Ian G Mills Search for more papers by this author Jason S Carroll Jason S Carroll Search for more papers by this author Jessica L L Robinson Jessica L L Robinson Search for more papers by this author Stewart MacArthur Stewart MacArthur Search for more papers by this author Caryn S Ross-Innes Caryn S Ross-Innes Search for more papers by this author Wayne D Tilley Wayne D Tilley Search for more papers by this author David E Neal David E Neal Search for more papers by this author Ian G Mills Ian G Mills Search for more papers by this author Jason S Carroll Jason S Carroll Search for more papers by this author Author Information Jessica L L Robinson, Stewart MacArthur, Caryn S Ross-Innes, Wayne D Tilley, David E Neal, Ian G Mills and Jason S Carroll The EMBO Journal (2012)31:1617-1617https://doi.org/10.1038/emboj.2012.59 This article corrects the following: Androgen receptor driven transcription in molecular apocrine breast cancer is mediated by FoxA124 June 2011 PDFDownload PDF of article text and main figures. ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InMendeleyWechatReddit Figures & Info Correspondence to: [email protected] Correction to: The EMBO Journal (2011) 30, 3019–3027. doi:10.1038/emboj.2011.216 Since the publication of this paper, the authors have noticed that the ArrayExpress accession numbers for the ChIP-seq and microarray data sets were not included. These are E-MTAB-986 (high-throughput sequencing experiments) and E-MTAB-987 (microarrays). The authors apologize for any inconvenience caused. Previous ArticleNext Article Read MoreAbout the coverClose modalView large imageVolume 31,Issue 6,March 21, 2012A puffin with the catch of the day, a bunch of sand eels. Several thousand pairs of these colourful birds breed on the Isle of May, a little island off the coast of Edinburgh. The photograph was taken by Ivan M. Muñoz, a Senior Research Associate of the MRC Protein Phosphorylation Unit in Dundee. Volume 31Issue 621 March 2012In this issue RelatedDetailsLoading ...

Plumage yellowness predicts foraging ability in the blue tit Cyanistes caeruleus

Carotenoid-based coloration in adult birds has been often regarded as an honest signal of individual quality. However, few studies have demonstrated a link between carotenoid display and the quantity or quality of resources provided to the offspring. The present study investigated the expression of a carotenoid-based ornament, the breast plumage yellowness of the blue tit Cyanistes caeruleus, in relation to the level of parental provisioning effort and the amount of carotenoid-rich prey provided to the young. The study was conducted in two forest types (evergreen and deciduous), which also allowed an exploration of the possible existence of habitat effects on the coloration of breeding birds. It was found that plumage colour intensity (carotenoid chroma) correlated positively with nestling provisioning rates of both males and females, supporting the good parent hypothesis. In addition, carotenoid chroma was positively related with the proportion of Lepidoptera larvae brought to the nest in both sexes. Female but not male coloration was positively linked to breeding success (proportion of fledged young). Nestling coloration did not correlate with that of their parents, nor the frequency with which they were fed. Hue and lightness of nestling’s plumage correlated positively with body mass and tarsus length, respectively. The results obtained in the present study indicate that ventral plumage coloration in blue tits may advertise the ingested carotenoids (carotenoid foraging ability) and also their overall parental quality in terms of nestling provisioning rates. This suggests that plumage yellowness can be used as an indicator of foraging ability in this species. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106, 418–429.