Adaptive Characteristics Of Herons Plumage For Their Way Of Life
Ð. I. Koshelev, V. Ð. Koshelev, V. I. Furmanova, L. V. Peresadko
Feather cover of each bird species reflects spectra of species, age, sex and environmental attributes defined the phylogeny of taxa, habitat and life patterns. In turn, many ecological phenomena in the birds’ life patterns are directly dependent on the state of plumage (e.g., time of breeding, seasonal migration, roost flights). For the first time the quantitative characterization of six heron species' plumage were done as well as the description of powder down feathers. The adaptive features of feathers and various types of heron’s plumages were discussed. The structure of contour feathers of herons is related to the peculiarities of species life pattern. All the species have a relatively small number of contour feathers, despite their large body size. According to this index the herons are more similar to typical wading birds (gulls, sandpipers) than for waterfowl. The total number of heron feathers slightly increase in winter, because they are migratory species. Structure of contour feathers of herons corresponds to that of other waterbirds. The rod is not bent, the feathers are large, and the mounting angle to the surface of the body is little. The cores of abdominal feather fracts reduce heat transfer and can be regarded as an adaptation factor to aquatic environment. Buoyancy is provided by heron’s feathers insignificantly, in contrast to the typical waterfowl species. Significant subcutaneous fat stores are typical for herons in spring, autumn and winter, increased buoyancy and being the energy reserves provide thermoregulation in cold environment. Our data indicate weak adaptation of herons’ plumage to aquatic environments, but also confirm its insulating properties, which is prove the herons semi-aquatic rather than aquatic life patterns. Due to color of plumage some three groups of herons were considered: white, mottled and camouflaged. Coloration of second and third group performs a protective function. We didn’t found a clear connection between the color of feathers and aquatic life pattern; only motley herons have aqueous two-color sign: the belly is lighter than the back.