Wesley W. Weathers

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Metabolism and insulation of monk parakeets were determined in summer and compared with previously reported winter values. Fasting levels of metabolism were the same in winter and summer during the daytime: nighttime values were significantly lower in winter (6.11 versus 8.20 Wkg-1). Evaporative water loss at 20–30° C was significantly lower in winter (2.24(More)
Plasma testosterone (T) levels in male dark-eyed juncos peak early in the breeding season, then decline. If T enhances opportunities for reproductive success, as suggested by previous experiments, why does elevated T not occur naturally? To address this question, we prolonged the early peak level throughout the breeding season and explored potential(More)
WEATHERS, WESLEY W., AND FRED N. WHITE. Physiological thermoregulafion in turtles. Am. J. Physiol. 22 l(3) : 704-7 10. 17 I. .The physiological capacity of turtles for altering rates of heat exchange was partially assessed by measuring rates of change of body temperature (Tb) during heating from 10 C to 30 C, and during cooling from 30 C to 10 C, in both(More)
We have experimentally validated a single-sample variant of the doubly labeled water method for measuring metabolic rate and water turnover in a very small passerine bird, the verdin (Auriparus flaviceps). We measured CO2 production using the Haldane gravimetric technique and compared these values with estimates derived from isotopic data. Doubly labeled(More)
We measured resting metabolic rates at air temperatures between ca. −5 and 30 °C in snow petrels (Pagodroma nivea), cape petrels (Daption capense), Antarctic petrels (Thalassoica antarctica), and Antarctic fulmars (Fulmarus glacialoides). We measured seven age classes for each species: adults, and nestlings that were 3, 8, 15, 28, 35, and 42 days old. Basal(More)
We used the doubly labeled water technique to measure daily energy expenditure (DEE) during the incubation and feeding nestling stages in two populations of white-crowned sparrows (Zonotrichia leucophrys) - one montane and migratory, the other coastal and sedentary - that differ in thermal environment and clutch size. We assessed the birds' thermal(More)
Monk parakeets have been introduced into North America within the past 15 years and are apparently becoming established in several geographical regions. Several physiological responses of monk parakeets related to climatic tolerance were examined, and it is concluded that the species is equipped physiologically to occupy most climatic situations with the(More)
Short-term heat stress can occur when chicks are transported from the hatchery to growing facilities. Two experiments were conducted to determine the possible effects of short-term heat stress on growth and feed conversion of broiler (Hubbard X Hubbard) chicks. The heat stress was accomplished by placing chicks in Jamesway 252 incubators at dry bulb(More)