Bird Energetics: Effects of Artificial Radiation

Abstract

Radiant energy reduces oxygen consumption in birds; this reduction is correlated with feather color, being greater in dark birds (26 percent reduction) than in white ones (6 percent reduction). With radiant energy (basking), the cow-bird effectively increased its insulation, thus shifting the lower end of the zone of thermal neutrality down by as much as 10 degrees C (35 degrees to 25 degrees C).

Thermal consequences of turning white in winter: a comparative study of red grouse Lagopus lagopus scoticus and Scandinavian willow grouse L. l. lagopus

“…The structure and optical properties of the plumage influence the amount of radiative heat that reaches skin level (Cena & Monteith 1975, Walsberg 1983b, 1992. This proportion of solar radiation has the capacity to influence thermal balance and metabolism (Lustick 1969, Ohmart & Lasiewski 1971, Wolf & Walsberg 1996, especially at ambient temperatures outwith the thermoneutral zone (Calder & King 1974, Walsberg 1983a, Wolf & Walsberg 1996. In cold environments any radiative heat that increases heat load on a bird would reduce the energy cost of thermoregulation.…”

“…Colouration at the plumage surface influences the reflectivity to incoming short-wave solar radiation irrespective of the environment that the bird inhabits, as well as the proportion of long-wave radiative heat that penetrates into the feather layer (Hamilton & Heppner 1967, Lustick 1969, Cena & Monteith 1975, Lustick et al 1980, Walsberg 1983b, 1988, 1992. The structure and optical properties of the plumage influence the amount of radiative heat that reaches skin level (Cena & Monteith 1975, Walsberg 1983b, 1992.…”

“…Similarly, the colour patterns of plumage are usually explained as devices for both inter-and intra-specific signalling and social recognition (Krebs 1979, Walsberg 1982, Guilford & Stamp Dawkins 1991. There is little doubt that avian colouration does have important functions in crypsis and social signalling; however, this need not be the only fitness consequence of colouration, and several studies have indicated that there may be significant thermal implications of plumage colouration for a bird in a given environment (Hamilton & Heppner 1967, Lustick 1969, Cena & Monteith 1975, Walsberg 1983b, 1988, Louw 1993.…”

Field Experiments On the Adaptive Significance of Avian Eggshell Pigmentation

“…During such circumstances dark cryptic eggshell pigmentation could be disadvantageous to the developing embryos. HAMILTON & HEP'PNER (1967;HEPPNER, 1970) and LuSTICK (1969) showed that dark and melanistic plumage can function to reduce the metabolic energy expenditure of birds when ambient temperature is below basal body temperature levels, such as at dawn and dusk. Surely a similar advantage might accrue to uncovered dark eggs at these times.…”

The screech owl : its life history and population ecology in northern Ohio /

“…The most important natural predator of the screech owl would probably be the great horned owl (Craighead and Craighead 1956), but we are doubtful that predators over a very short term could be responsible for the major change in color phase ratios in 1951. Lustick (1969) studied the effects of artificial radiation on bird energetics and concluded that radiant energy reduces oxygen consumption in birds and that the reduction is correlated with feather color, being greater in dark birds. Mosher and Henny (in press) recently conducted metabolic experiments with screech owls to attempt to ascertain.…”