TABLE 1.

Results of recent studies (since 2010) of natural seasonal or migratory acclimatization, temperature acclimation, or experimental flight training effects on pectoralis/flight muscle mass or size and metabolic rates (BMR or M_sum) in birds.

Species	Acclimatization or acclimation condition	Trend in pectoralis muscle mass or size	Trend in metabolic Rates	Reference
Black-capped chickadee	Seasonal acclimatization to cold winter	Dry mass increase by 10%	Msum increase by 22%	Petit et al. (2014)
Poecile atricapillus
Snow bunting	Outdoor captive all year in winter range	Ultrasound thickness increase by 8%	Msum increase by 23%	Le Pogam et al. (2020)
Plectrophenax nivalis
Chinese bulbul	Seasonal acclimatization to cool winter	Dry mass increase by 12%	BMR increase by 21%	Zheng et al. (2014)
Pycnonotus sinensis
Chinese hwamei	Acclimated to 15 and 35°C	Dry mass increase by 20%	BMR increase by 40%	Zhou et al. (2016)
Garrulax canorus
Eurasian tree sparrow	Acclimated to 10 and 30°C; varying photoperiod	No sig. change in dry mass of skeletal muscle	BMR increase by 45%	Li et al. (2020)
Passer montanus
Chinese bulbul	Seasonal acclimatization to cool winter	No sig. change in dry mass	BMR increase by 42%	Wang et al. (2019)
Pycnonotus sinensis
Chinese hwamei	Acclimated to 10 and 30°C; varying photoperiod	No sig. change in dry mass	BMR increase by 18%	Hu et al. (2017)
Garrulax canorus
Dark-eyed junco	Acclimated to 3 and 24°C; varying photoperiod	No significant change in wet mass	Msum increase by 18%	Swanson et al. (2014a)
Junco hyemalis
White-throated sparrow	Acclimated to -8 and 28°C	No sig. change in dry mass	Msum increase by 19%	Barcelo et al. (2017)
Zonotrichia albicollis			BMR increase by 15%
Black-capped chickadee	Acclimated to -10 and 27°C	No sig. change in dry mass	Msum increase by 20%	Milbergue et al. (2018)
Poecile atricapillus			BMR increase by 5%
Snow bunting	Seasonal acclimatization cold winter, Arctic summer	Winter ultrasound thickness increase by 3.1%	No significant change in Msum	Le Pogam et al. (2021)
Plectrophenax nivalis
White-browed sparrow-weaver	Seasonal acclimatization to mild winter	Dry mass increase by 5%	Msum decrease by 26%	Noakes et al. (2020)
Plocepasser mahali
House sparrow	Acute, repeated exposure to severe cold	Wet mass increase by 5%	Msum increase by 14.6%	Zhang et al. (2015)
Passer domesticus			BMR increase by 10.3%
Gray catbird	Natural migratory acclimatization	Wet mass increase by 8.7% in migrants	Msum increase by 19-29%	DeMoranville et al. (2019)
Dumetella carolinensis
Warbling vireo	Natural migratory acclimatization	Wet mass increase by 10.3% in spring	Msum increase by 18.3%	King et al. (2015)
Vireo gilvus				Swanson (1995)
Yellow warbler	Natural migratory acclimatization	Wet mass increase by 14.7% in spring	Msum increase by 23.3%	King et al. (2015)
Setophaga petechia				Swanson and Dean (1999)
Yellow-rumped warbler	Natural migratory acclimatization	No significant seasonal change in wet mass	Msum increase by 19.8% in spring vs. fall	King et al. (2015)
Setophaga coronata				Swanson and Dean (1999)
Black-capped chickadee	Feather clipping to increase flight costs	Muscle score increase	Msum increase by 17%	Petit and Vézina (2014a)
Poecile atricapillus
House sparrow	Experimental flight training	Wet mass increase by 7%	Msum increase by 15.5%	Zhang et al. (2015)
Passer domesticus			BMR decrease by 37.9%