Effects of endurance flight on mitochondrial physiology, lean mass dynamics and flight muscle morphology in blackpoll warblers

Migratory birds are physiologically challenged by intense exercise while fasting during flights that may last hours to days. Exercise-induced oxidative stress could compromise flight performance by inducing mitochondrial dysfunction in the flight muscle. Endurance flight is partially fuelled by the catabolism of lean tissues, but how this catabolism is partitioned between different organs and muscles has not been previously studied under controlled conditions. We hypothesized that simulated migratory flight would result in dysfunction of flight muscle mitochondria, and selective catabolism of lean tissues. We predicted that simulated migratory flight would cause reduced mitochondrial oxidative phosphorylation capacity while increasing emission of reactive oxygen species (ROS) and that lean tissue mass catabolism would preferentially occur in digestive organs not needed in flight. We measured mitochondrial function, muscle morphology and the wet masses of organs and muscles following 8-h..., , , # Effects of endurance flight on mitochondrial physiology, lean mass dynamics and flight muscle morphology in blackpoll warblers

[https://doi.org/10.5061/dryad.s4mw6m9hc](https://doi.org/10.5061/dryad.s4mw6m9hc)

## Description of the data and file structure

Blackpoll warblers (*Setophaga striata*) were split into three experimental groups and each was fasted for one hour prior to each group's intervention:

1. Flown: birds were sampled after being flown 7.5-8 hours in a wind tunnel
2. Fasted: birds were sampled after being fasted from food and water for 7.5-8 hours in the wind tunnel antechamber
3. Pre-flight: birds were sampled following the 1 hour fast

Body composition for flown and fasted birds was measured before and after flight/fasting using quantitive magnetic resonance imaging. After euthanasia, multiple tissues were harvested and weighed. Some flight muscle was embedded for histological analyses, while remaining muscle was used to isolate mitochondria. High-resolution respi...