Energetics of nestling growth and parental effort in Antarctic fulmarine petrels.

Antarctic fulmarine petrels breed in some of the coldest conditions encountered by any bird and their young grow twice as fast as predicted allometrically. To examine the energetic consequences of fast growth in a cold environment, we used the doubly labeled water technique to measure field metabolic rates of adults (three species) and different-aged nestlings (four species) of Antarctic fulmarine petrels in the Rauer Islands, East Antarctica: Antarctic fulmar Fulmarus glacialoides, Antarctic petrel Thalassoica antarctica, Cape petrel Daption capense and snow petrel Pagodroma nivea. We used our data to assess parental effort and, together with literature values on nestling growth and resting metabolic rate, to construct and partition nestling energy budgets.

Altitudinal variation in parental energy expenditure by white-crowned sparrows.

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 environment by continuously monitoring (among other variables) operative temperature and wind speed both in the open and within bushes and willow thickets occupied by sparrows. From these measurements, we derived several estimates of the birds' thermal environment, including standard operative temperature (T(es)).

Effects of weather on daily body mass regulation in wintering dunlin.

We investigated the influence of changes in weather associated with winter storms on mass balance, activity and food consumption in captive dunlin (Calidris alpina) held in outdoor aviaries, and compared the aviary results with weather-related body mass differences in free-living dunlin collected at Bolinas Lagoon, California. Captive birds fed ad libitum increased their body mass at higher wind speeds and lower temperatures, suggesting regulation of energy stores, whereas free-living birds exhibited patterns suggesting thermoregulatory limits on body mass regulation. Daily energy expenditure in aviary dunlin was 2.

Climatic adaptation in Svian standard metabolic rate.

The standard metabolic rate (SMR) of birds correlates broadly with climate of origin. SMR tends to be higher in birds from cold climates and lower in tropical forms than would be expected from the bird's mass. SMR changes, on the average, 1% per degree change in latitude.

Seasonal acclimatization to temperature in monk parakeets.

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.

Temperature regulation and water requirements of the monk parakeet, Myiopsitta monachus.

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 exception of arctic and subarctic regions and waterless deserts. The standard metabolic rate, determined during the winter, was 44% lower at night (1.