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Riegner, Mark F. "Parallel Evolution of Plumage Pattern and Coloration in Birds: Implications for Defining Avian Morphospace." The Condor. 110.4 (2008): 599-614. Print. This article focuses on whether or not birds of brightly colors or patterns are contributed to morphological features such as size or anterior emphasis. Have these colors and patterns stayed the same through generations or were there changes. The methods that were used in this study were, examining plumage patterns in over 3600 species in 98 non-passerine families and of over 4700 species in 82 passerine families. Along with plumage, body size and weight were compared. Results for this study showed that streaks were often associated with birds of a small compact or slender-bodied. While bars were shown to be more frequent in large-bodied species, with some exceptions. The conclusion that can be taken away is pattern element in birds may change from taxon to taxon and has led to understatement of a parallel evolution. Not all species fit with this study and along the way mutations has occurred in some species leading to changes over generations. This article will be helpful when I begin to discuss how different species of birds have either bright colors or certain patterns, whether or not these colors and patterns have always been that way for that particular species or have there been events or changes over time that have led to differences within a particular species.

Stoddard, Mary C, and Richard O. Prum. "How Colorful Are Birds? Evolution of the Avian Plumage Color Gamut." Behavioral Ecology. 22.5 (2011): 1042-1052. Print. Study is looking at the evolution of bright colors in bird plumage. They want to know if the colors have evolved out of sensory reasons such as signal use. They also want to know if physical, developmental or physiological constraints make a difference. They also look at the flowers and vegetation around these species and see that plays a part. They know they want to know how birds see color and weather they are able to see more color than humans. For the methods of this study the use a wide variety of plumage patches of male specimens of 111 species. They used a special optics spectrometer to read the colors of the specimens. The colors were split into subgroups: melanins, carotenoids, porphyrins, psittacofulvins, structural, white or combination. They tested each bird’s vision cones and how they take in the color and how many colors they can actually see. The results, of this study show that out of the 965 plummage colors measured only occupied about 26% of the total available to the VS cone-type avian color space. They found that the cone that sees and processes color in bird’s eyes did not evolve specifically to broaden diversity of plumage. The conclusion is that plumage color is not uniformly distributed in color space but instead forms distinct areas that are separated by unoccupied hue regions. Feather color only makes up a small volume of avian plumage gamut. This study will help me with the whys of birds having brightly colored plumage and how birds take in bright colors. All the information in this study won’t be useful but it does bring new information that I haven’t really considered, such as do birds coloring have anything to do with plant species around them.

Dunn, Peter O, Linda A. Whittingham, and Trevor E. Pitcher. "Mating Systems, Sperm Competition, and the Evolution of Sexual Dimorphism in Birds." Evolution. 55.1 (2001): 161-175. Print. This study is looking at sexual dimorphism in birds and how different factors such as bright colors and size. They are looking at different mechanisms my produce different types of sexual dimorphism. The method for this study includes collecting data on size and plumage from both museum specimens and literature. They scored the plumage dimorphism on a scale from 0 (monomorphic)-10 (maximum dimorphism), they scored over five regions of the body. For type of morphisms they classified them such as seasonal, yearly-round…they also examined social mating systems and testis mass. They found that plumage dimorphism was associated with social mating systems. They found that plumage was greatest in Lek species and smaller in polygnous species and smallest among all types of other mating systems. They also found that plumage was related to nest height and geographic area. The overall is that they found that sexual dimorphisms in size and plumage are related to traditional classification of mating systems. More recent studies found that sperm competition is more important to the evolution of sexual dimorphism in birds. This information is useful, since most of the times we think that birds brightly colored feathers are to do with sexual reproduction. This study not only discusses but also looks at other related issues to sexual dimorphism. This will help me when talking about the importance of colors for mating and how evolution has helped with that.

Coyne, Jerry A, Emily H. Kay, Stephen Pruett-Jones, and J True. "The Genetic Basis of Sexual Dimorphism in Birds." Evolution. 62.1 (2008): 214-219. Print. For this study they are examining how sexual dimorphism in color of plumage becomes most dominate in males. They also take a look at how alleles could become male-specific over time. They also bring up the how hybridization between species and sexes happens. For the methods they searched for hybrid females in books and talked to ornithologists and bird curators. They narrowed the search down to hybrid females between sexually dimorphic species with males that have different ornamental traits. The results of this study found that F1 female hybrids do not show sexual dimorphic traits seen in the males of the parental species. They concluded that male-limited traits evolved in either or two ways. 1. Alleles responsible for traits from their initial appearance expressed only in males. 2. Alleles responsible for such traits were expressed both sexes but were either suppressed in females or are limited to males. This study is helpful, because when looking at bird species, not all males are the only ones to have bright colored plumage; some females of some species also display color. This will help in understanding why these species would have females just as colorful as the males.

GLUCKMAN, T.-L, and G C. CARDOSO. "The Dual Function of Barred Plumage in Birds: Camouflage and Communication." Journal of Evolutionary Biology. 23.11 (2010): 2501-2506. Print. This study looks at how birds feathers especially barred plumage is a common trait in birds. They want to know how important this trait is to communication and camouflage. While colors are not always the same throughout species, barred plumage is more highly regular. Has the barred plumage evolved because of camouflage or signaling functions. For this study they examined over 90% of all avian species for pigmentation patterns, they looked at adult male, females and juveniles. They used mottled patterns as a control for comparison. They looked to see if the barred patterns were shown ventrally or dorsally. The results of this study showed that families where multiple species have barred plumage ventrally are predominantly present in both sexes. Species with barred females was more frequent than in males, they concluded that camouflage is the most common function for barred plumage. While the mottled feathers, were more for signaling. This study was useful for why certain patterns are used in birds, this is showing that not all birds use bright colors and other patterns were developed to help with certain species needs.