An exploratory comparison of region-specific feather microstructure in two Eurasian tree sparrow populations across altitudes
- 1Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
- 2Hebei Collaborative Innovation Center for Eco-Environment, Hebei Normal University, Shijiazhuang, China
- 3Cangzhou Normal University College of Life Science, Cangzhou, China
Abstract
High-altitude environments impose simultaneous challenges to avian flight and thermoregulation, potentially shaping variation in feather microstructure. We conducted an exploratory comparison of feather microstructural traits across feather regions, sexes, and altitudinal populations in the Eurasian tree sparrow ( Passer montanus ). Using scanning electron microscopy, we quantified vane- and downy- feather traits, including barbule length and density, hamuli number, cilia number, ventral teeth number, and internode length and width. We further complemented these analyses with thermogravimetric and calorimetric measurements of breast feathers. Our results showed that feather microstructure was strongly region-specific: tail and wing feathers consistently exhibited interlocking structures (similar hamuli, cilia, and ventral teeth), whereas back and breast feathers showed nodal features. In contrast, population- and sex-associated variation appeared limited and localized to body-feather nodal architecture: high-altitude (HA) females had longer breast internodes than low-altitude (LA) females, and breast internodes were narrower than back internodes in LA birds but not in HA birds. Thermogravimetric and calorimetric analyses revealed similar breast-feather decomposition profiles between populations, consistent with no major difference in keratin thermal decomposition. Our results suggest that feather microstructure in this widespread species is primarily dominated by feather-region specialization, with preliminary evidence of localized population- and sex-associated variation.
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BibTeX
@article{liu2026exploratory,
title = {{An exploratory comparison of region-specific feather microstructure in two Eurasian tree sparrow populations across altitudes}},
author = {Fangyuan Liu and Tonghe Zhang and Xu Liu and Qian Zhang and Tiantian Zhang and Juyong Li and Minghui Zhao and Guanqun Kou and Limin Wang and Yang Wang and Dongming Li},
journal = {PeerJ},
year = {2026},
month = oct,
doi = {10.7717/peerj.21803},
url = {https://peerj.com/articles/21803},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - An exploratory comparison of region-specific feather microstructure in two Eurasian tree sparrow populations across altitudes
AU - Fangyuan Liu
AU - Tonghe Zhang
AU - Xu Liu
AU - Qian Zhang
AU - Tiantian Zhang
AU - Juyong Li
AU - Minghui Zhao
AU - Guanqun Kou
AU - Limin Wang
AU - Yang Wang
AU - Dongming Li
PY - 2026
DA - 2026/10/22
JO - PeerJ
DO - 10.7717/peerj.21803
UR - https://peerj.com/articles/21803
AB - High-altitude environments impose simultaneous challenges to avian flight and thermoregulation, potentially shaping variation in feather microstructure. We conducted an exploratory comparison of feather microstructural traits across feather regions, sexes, and altitudinal populations in the Eurasian tree sparrow ( Passer montanus ). Using scanning electron microscopy, we quantified vane- and downy- feather traits, including barbule length and density, hamuli number, cilia number, ventral teeth number, and internode length and width. We further complemented these analyses with thermogravimetric and calorimetric measurements of breast feathers. Our results showed that feather microstructure was strongly region-specific: tail and wing feathers consistently exhibited interlocking structures (similar hamuli, cilia, and ventral teeth), whereas back and breast feathers showed nodal features. In contrast, population- and sex-associated variation appeared limited and localized to body-feather nodal architecture: high-altitude (HA) females had longer breast internodes than low-altitude (LA) females, and breast internodes were narrower than back internodes in LA birds but not in HA birds. Thermogravimetric and calorimetric analyses revealed similar breast-feather decomposition profiles between populations, consistent with no major difference in keratin thermal decomposition. Our results suggest that feather microstructure in this widespread species is primarily dominated by feather-region specialization, with preliminary evidence of localized population- and sex-associated variation.
SN - 2167-8359
ER -