Pigeon Bird Wallpaper Biography
Harris' Sparrows assemble in flocks of mixed ages in the winter. Individuals within the flocks show a great deal of variation in their plumage characteristics, especially in the amount of darkness on their heads and "bibs." In a series of experiments Rohwer darkened relatively light first-year birds with dye to make them look like adults. He found, for example, that dyed first-year birds are initially avoided by undyed "control" first-year birds. Then the dyed birds began actively to dominate the controls. Rohwer thus concluded that the dominance status of a Harris' Sparrow can be communicated by a badge, a dark head and bib. The alternate explanation (that the dye in some way actually enhanced the combat ability of dyed birds) is too unlikely to merit serious consideration.
Differences in darkness do not, however, always correlate with status, as behaviorist Doris Watt has shown. In experiments Watt showed that within age classes, at least in small groups, darker birds are not always dominant over lighter individuals. She believes the darkness to be basically a badge of age, which signals to first-year birds the potential dominance of adults. Apparently among both young and adults, variation in breast spot patterns (as opposed to overall breast darkness) aids individuals in recognizing one another, but does not indicate status.
Harris' Sparrows assemble in flocks of mixed ages in the winter. Individuals within the flocks show a great deal of variation in their plumage characteristics, especially in the amount of darkness on their heads and "bibs." In a series of experiments Rohwer darkened relatively light first-year birds with dye to make them look like adults. He found, for example, that dyed first-year birds are initially avoided by undyed "control" first-year birds. Then the dyed birds began actively to dominate the controls. Rohwer thus concluded that the dominance status of a Harris' Sparrow can be communicated by a badge, a dark head and bib. The alternate explanation (that the dye in some way actually enhanced the combat ability of dyed birds) is too unlikely to merit serious consideration.
Differences in darkness do not, however, always correlate with status, as behaviorist Doris Watt has shown. In experiments Watt showed that within age classes, at least in small groups, darker birds are not always dominant over lighter individuals. She believes the darkness to be basically a badge of age, which signals to first-year birds the potential dominance of adults. Apparently among both young and adults, variation in breast spot patterns (as opposed to overall breast darkness) aids individuals in recognizing one another, but does not indicate status.
Pigeon Bird Wallpaper
Pigeon Bird Wallpaper
Pigeon Bird Wallpaper
Pigeon Bird Wallpaper
Pigeon Bird Wallpaper
Pigeon Bird Wallpaper
Pigeon Bird Wallpaper
Pigeon Bird Wallpaper
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