Estimates of a trait heritability and repeatability can get at an idea of its usefulness for being an individual characteristic and its ability to change under selection pressure. Heritability and repeatability of energetic parameters still poorly studied in birds. The most important physiological characteristic of homoiotherms is resting metabolic rate (RMR), which, in the absence of productive processes, does not exceed basal metabolic rate (BMR). We estimated BMR repeatability in free-living pied flycatchers in Moscow Region (55 degrees 44' N, 36 degrees 51' E; 1992-2008) and Tomsk (56 degrees 20' N, 84 degrees 56' E; 2008-2009) populations over intervals from 40 days to 3 years. In Moscow Region population, BMR repeatability amounted to tau = 0.34 +/- 0.10 (n=80) if measured over 1 year interval, tau = 0.60 +/- 0.15 (n=19) if measured over 2 years interval, and tau = 0.85 +/- 0.13 (n=6) if measured over 3 years interval providing that consecutive BMR measurements were done in the same period of reproductive season. In Tomsk population, BMR repeatability, measured over 1 year interval, amounted to tau = 0.49 +/- 0.11 (n=50). Repeatability is a measure of a trait constancy and sets the upper limit of its heritability. To estimate RMR heritability, cross-fostering experiments have been conducted in 2003-2005 with flycatchers of Moscow Region population. RMR of chicks positively correlated with BMR of their biological fathers, whereas such correlation in metabolic rates between chicks and their foster fathers was absent. The RMR heritability estimate turned out to be h2 = 0.43 +/- 0.17 (n=210). The obtained estimates of heritability and repeatability of fundamental energetic traits are rather high for physiological features. This suggests the existence of a potential for direct selection on BMR and evolutionary stable diversity of avian populations with regard to basal metabolic rate.