نتایج جستجو برای: feathers
تعداد نتایج: 2568 فیلتر نتایج به سال:
Studies of avian migration increasingly use stable isotope analysis to provide vital trophic and spatial markers. However, when interpreting differences in stable isotope values of feathers, many studies are forced to make assumptions about the timing of moult. A fundamental question remains about the consistency of these values within and between feathers from the same individual. In this stud...
1. Recent studies in Scotland suggest that the outermost tail feathers of Barn Swallows ( Hirundo rustica Linnaeus) may be around 10–12 mm longer than the aerodynamic optimum, with sexual selection for long tails accounting for this extra length. 2. To test this hypothesis, we shortened the outermost tail feathers in male and female Barn Swallows in southern Spain by cutting 1, 11 or 21 mm from...
T H E foot of developing embryos of scalefooted varieties of the common domestic fowl (Silver Campine, White Leghorn and others) frequently exhibits feather primordia emerging from the scales of various regions. Many of the feather germs are rudimentary and disappear by the time of hatching, but some persist and differentiate into normal feathers. Such feathers are often inconspicuous and easil...
The flight feathers and their coverts of a European kestrel Falco tinnunculus have been tested for their air transmissivity. The transmissivity was measured in both directions, i.e. from ventral to dorsal and vice versa; the mean difference between the two directions was less than 10 %. However, the transmissivity of the inner versus outer vanes of the remiges and coverts differed significantly...
Feather waste is generated in large amounts as a by-product of commercial poultry processing. This residue is almost pure keratin, which is not easily degradable by common proteolytic enzymes. Eight strains of Bacillus, isolated from decomposing feathers were tested for the hydrolysis of feather wastes in the laboratory. Among these strains, Bacillus cereus KB043 was the best feather degrading ...
Birds in the cormorant (Phalacrocoracidae) family dive tens of metres into water to prey on fish while entraining a thin layer of air (a plastron film) within the microstructures of their feathers. In addition, many species within the family spread their wings for long periods of time upon emerging from water. To investigate whether wetting and wing-spreading are related to feather structure, m...
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