Article Abstract:
The utility of isotopic potassium in the estimation of fat mass of birds was tested using the carcasses of 29 pigeons, Columba livia. This noninvasive technique relies on the fixed ratio between isotopic and total potassium in the body, to the presence of potassium in lean tissue and its absence from adipose tissue. Regression analyses were conducted to evaluate the utility of this method. Results reveal that the measurement of isotopic potassium cannot accurately predict fat mass in pigeons.
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Article Abstract:
A new study investigates whether the red coloring of adult male Northern Cardinals acts as a status symbol during interactions over food sources in the winter. Results show that adult male Northern Cardinals do not use red coloration as a status signal when defending food resources but redder males appear to be more dominant and coloration may be used as an indicator in other conditions, such as defending breeding territories or signaling to females.
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Article Abstract:
The body composition of Barn Owls during the nonbreeding period was examined to characterize seasonal changes. Sex, age and gender affected structural size and nutritional status. The nutritional status of Barn Owls during the nonbreeding period was based on captive birds on road-killed samples. Barn Owls revealed an accumulation of lipid reserves in preparation for a cold weather and food scarcity.
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