Linking performance to powerhouse: Mitochondria functions in blood cells reflect flight endurance of a songbird

Identifying the physiological mechanisms underpinning inter-individual differences in performance and fitness remains a key challenge in organismal biology. Variation in mitochondrial aerobic metabolism has been suggested to underlie inter-individual variation in performance, but this remains seldom tested, partly because of the need to use terminal sampling for assessing mitochondrial parameters. To fill this knowledge gap, we investigated whether inter-individual variation in mitochondrial aerobic parameters measured from less-invasively taken samples (i.e., blood cells) would correlate with both anaerobic and aerobic metrics of flight performance in house sparrows (Passer domesticus). We predicted that mitochondrial aerobic metabolism should correlate with aerobic but not anaerobic metrics of flight performance. As expected, we found no evidence for a relationship between mitochondrial metabolism and the energy required to take-off (i.e., anaerobic), but flight duration to exhaustion..., , # Linking performance to powerhouse: Mitochondria functions in blood cells reflect flight endurance of a songbird

Dataset DOI: [10.5061/dryad.bnzs7h4nr](10.5061/dryad.bnzs7h4nr)

## Description of the data and file structure

We captured a total of 53 wild female adult house sparrows using mist nets in the three Australian cities/towns of Broken Hill (n = 34) Denman (n = 6), and Branxton (n = 13), in New South Wales, between the 20th and the 26th of May 2023 (Macquarie University Animal Ethics Committee ARA #2020/011). We used adult females to avoid introducing variation in mitochondrial aerobic metabolism related due to sex and age. Groups of three females were housed together in 18 indoor cages 60´80´46 cm (height ´ width ´ depth). All the cages were in the same climate-controlled room kept at a mean ± SD 23.34 ± 0.57 ºC and exposed to an 11:13 hour cycle of light and darkness. Each cage contained at least one subject from each location when possible (Broken Hill, Denman, and Branxto...,