{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,20]],"date-time":"2026-04-20T08:51:22Z","timestamp":1776675082947,"version":"3.51.2"},"reference-count":137,"publisher":"Oxford University Press (OUP)","issue":"1","license":[{"start":{"date-parts":[[2026,4,2]],"date-time":"2026-04-02T00:00:00Z","timestamp":1775088000000},"content-version":"vor","delay-in-days":91,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000001","name":"National Science Foundation","doi-asserted-by":"publisher","award":["IOS-1755128"],"award-info":[{"award-number":["IOS-1755128"]}],"id":[{"id":"10.13039\/100000001","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,1,14]]},"abstract":"<jats:title>Synopsis<\/jats:title>\n                  <jats:p>Organisms in natural environments often undergo life history stage transitions that optimize behaviors (i.e., migration, reproduction, and foraging) with environmental conditions. These changes in behavior are facilitated by changes in physiology such as metabolism and energy production. Previous work on seasonally breeding songbirds observed that elevated levels of sex steroids during reproduction are accompanied by increases in basal metabolic rate (BMR), the minimum energy required to live for an adult organism. This increase in BMR is also associated with increasing daylengths in long-day seasonally breeding animals. Whether, and to what extent, the seasonal increase in BMR is a direct result of testosterone or in response to increases in duration and amount of activity occurring during longer days is not fully known. Experimental studies indicate that testosterone is capable of modulating mitochondrial function through activation of androgen and estrogen receptors within the mitochondria. However, whether testosterone directly influences BMR, and if it is related to changes in mitochondrial abundance remains unclear. Mitochondrial abundance can be quantified by assessing mitochondrial DNA copy number (mtDNAcn) which has been positively correlated with oxidative capacity and ATP production. Here, we assessed BMR of individual male house sparrows (Passer domesticus) during three experimental treatment periods: non-breeding short day photoperiods prior to hormonal manipulation (SD), followed by testosterone implants while still on non-breeding short days (SD\u00a0+\u00a0T), and then photostimulated on long days (LD) after implant removal, mimicking natural breeding conditions. We also collected blood samples to quantify testosterone and mtDNAcn of red blood cells (RBC mtDNAcn). Our results indicate testosterone did not directly alter BMR and that BMR was only elevated under longer daylengths associated with longer active periods. The total minutes of the day the birds were active increased under LD, thus indicating activity, and not increases in sex hormones, is likely responsible for the increases in BMR. We also observed no effect of treatment period on RBC mtDNAcn. Combined, the results from this study indicate that testosterone is not affecting BMR through changes in mitochondrial density (mtDNAcn) in red blood cells. However, changes in photoperiod affected BMR by either increasing daily activity or by stimulating the growth of reproductive tissues in seasonally breeding birds.<\/jats:p>","DOI":"10.1093\/iob\/obag013","type":"journal-article","created":{"date-parts":[[2026,3,31]],"date-time":"2026-03-31T11:30:44Z","timestamp":1774956644000},"source":"Crossref","is-referenced-by-count":0,"title":["Photoperiod, but not testosterone, increases basal metabolic rate in house sparrows"],"prefix":"10.1093","volume":"8","author":[{"ORCID":"https:\/\/orcid.org\/0009-0009-5435-5513","authenticated-orcid":false,"given":"H","family":"Galante","sequence":"first","affiliation":[{"name":"North Dakota State University Department of Biological Sciences, , Fargo, ND 58108 ,","place":["USA"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"S J","family":"Lane","sequence":"additional","affiliation":[{"name":"North Dakota State University Department of Biological Sciences, , Fargo, ND 58108 ,","place":["USA"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7112-9560","authenticated-orcid":false,"given":"E K","family":"Elderbrock","sequence":"additional","affiliation":[{"name":"North Dakota State University Department of Biological Sciences, , Fargo, ND 58108 ,","place":["USA"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"J D","family":"Kittilson","sequence":"additional","affiliation":[{"name":"North Dakota State University Department of Biological Sciences, , Fargo, ND 58108 ,","place":["USA"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6595-5428","authenticated-orcid":false,"given":"K J","family":"Greenlee","sequence":"additional","affiliation":[{"name":"North Dakota State University Department of Biological Sciences, , Fargo, ND 58108 ,","place":["USA"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9239-1413","authenticated-orcid":false,"given":"T J","family":"Greives","sequence":"additional","affiliation":[{"name":"North Dakota State University Department of Biological Sciences, , Fargo, ND 58108 ,","place":["USA"]}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"286","published-online":{"date-parts":[[2026,4,2]]},"reference":[{"key":"2026042004060964500_bib2","doi-asserted-by":"publisher","first-page":"S17","DOI":"10.1007\/s10336-007-0188-3","article-title":"Hormones and the development of sex differences in behavior","volume":"148","author":"Adkins-Regan","year":"2007","journal-title":"J Ornithol"},{"key":"2026042004060964500_bib3","doi-asserted-by":"publisher","first-page":"C835","DOI":"10.1152\/ajpcell.00205.2022","article-title":"Role of androgens and androgen receptor in control of mitochondrial function","volume":"323","author":"Ahmad","year":"2022","journal-title":"Am J Physiol Cell Physiol"},{"key":"2026042004060964500_bib4","doi-asserted-by":"publisher","first-page":"3571","DOI":"10.1242\/jeb.205.22.3571","article-title":"Seasonal daily, daytime and night-time field metabolic rates in Arabian babblers (Turdoides squamiceps)","volume":"22","author":"Anava","year":"2002","journal-title":"J Exp Biol"},{"key":"2026042004060964500_bib5","doi-asserted-by":"crossref","DOI":"10.1093\/acprof:oso\/9780195304114.001.0001","volume-title":"Biology of the Ubiquitous House Sparrow: from Genes to Populations","author":"Anderson","year":"2006"},{"key":"2026042004060964500_bib6","doi-asserted-by":"crossref","first-page":"433","DOI":"10.1093\/condor\/107.2.433","article-title":"Seasonal and diurnal variation in metabolism and ventilation in house sparrows","volume":"107","author":"Arens","year":"2005","journal-title":"Condor"},{"key":"2026042004060964500_bib7","doi-asserted-by":"publisher","first-page":"631","DOI":"10.1242\/jeb.133678","article-title":"Repeatability of metabolic rate is lower for animals living under field versus laboratory conditions","volume":"219","author":"Auer","year":"2016","journal-title":"J Exp Biol"},{"key":"2026042004060964500_bib8","doi-asserted-by":"publisher","first-page":"185","DOI":"10.1080\/11250008009440335","article-title":"Effects of sex steroids on testosterone metabolism, plasma gonadotropins, cloacal gland growth and reproductive behaviour in the Japanese quail","volume":"47","author":"Balthazart","year":"1980","journal-title":"Ital J Zool"},{"key":"2026042004060964500_bib9","volume-title":"lme4: Mixed-effects Modeling with R Springer","author":"Bates","year":"2010"},{"key":"2026042004060964500_bib10","doi-asserted-by":"publisher","first-page":"1","DOI":"10.18637\/jss.v067.i01","article-title":"Fitting linear mixed-effects models using lme4","volume":"67","author":"Bates","year":"2015","journal-title":"J Stat Softw"},{"key":"2026042004060964500_bib11","doi-asserted-by":"publisher","first-page":"109","DOI":"10.14715\/cmb\/2016.62.12.19","article-title":"The effects of mitochondrial DNA deletion and copy number variations on different exercise intensities in highly trained swimmers","volume":"62","author":"Baykara","year":"2016","journal-title":"Cell Mol Biol (Noisy-le-grand)"},{"key":"2026042004060964500_bib12","doi-asserted-by":"publisher","first-page":"2161","DOI":"10.1098\/rspb.1999.0903","article-title":"Repeatability of basal metabolism in breeding female kittiwakes Rissa tridactyla","volume":"266","author":"Bech","year":"1999","journal-title":"Proc R Soc London, Ser B"},{"key":"2026042004060964500_bib14","doi-asserted-by":"publisher","first-page":"276","DOI":"10.1006\/gcen.1996.6829","article-title":"Photoperiodic condition modulates the effects of testosterone on song control nuclei volumes in male European starlings","volume":"105","author":"Bernard","year":"1997","journal-title":"Gen Comp Endocrinol"},{"key":"2026042004060964500_bib15","doi-asserted-by":"publisher","first-page":"189","DOI":"10.1016\/S0303-7207(01)00427-0","article-title":"Photoperiod-dependent capability of androgen aromatization and the role of estrogens in the bank vole testis visualized by means of immunohistochemistry","volume":"178","author":"Bilinska","year":"2001","journal-title":"Mol Cell Endocrinol"},{"key":"2026042004060964500_bib16","doi-asserted-by":"publisher","first-page":"357","DOI":"10.2307\/1937540","article-title":"Activity-specific metabolic rates of free-living Northern gannets and other seabirds","volume":"70","author":"Birt-Friesen","year":"1989","journal-title":"Ecol Soc Am"},{"key":"2026042004060964500_bib17","doi-asserted-by":"publisher","first-page":"1679","DOI":"10.1098\/rspb.2008.1817","article-title":"Telomere dynamics rather than age predict life expectancy in the wild","volume":"276","author":"Bize","year":"2009","journal-title":"Proc R Soc B Biol Sci"},{"key":"2026042004060964500_bib18","doi-asserted-by":"publisher","first-page":"779","DOI":"10.1093\/auk\/104.4.779","article-title":"Sexing monomorphic birds by vent measurements","volume":"104","author":"Boersma","year":"1987","journal-title":"Auk"},{"key":"2026042004060964500_bib19","doi-asserted-by":"publisher","first-page":"642","DOI":"10.1101\/721779","article-title":"Metabolic rate is negatively linked to adult survival but does not explain latitudinal differences in songbirds","volume":"23","author":"Boyce","year":"2020","journal-title":"Ecol Lett"},{"key":"2026042004060964500_bib1a","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1101\/cshperspect.a019000","article-title":"Neurogenesis in the adult avian song-control system","volume":"7","author":"Brenowitz","year":"2015","journal-title":"Cold Spring Harb Perspect Biol"},{"key":"2026042004060964500_bib20","doi-asserted-by":"publisher","first-page":"768","DOI":"10.1111\/j.1365-2435.2009.01561.x","article-title":"Long-term repeatability of winter basal metabolic rate and mass in a wild passerine","volume":"23","author":"Broggi","year":"2009","journal-title":"Source Funct Ecol"},{"key":"2026042004060964500_bib21","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1186\/s40317-023-00327-0","article-title":"An open-source platform for sub- g, sub- \u03bc A data loggers","volume":"11","author":"Brown","year":"2023","journal-title":"Anim Biotelemetry"},{"key":"2026042004060964500_bib22","doi-asserted-by":"publisher","first-page":"261","DOI":"10.1016\/0016-6480(77)90251-9","article-title":"Effects of androgens on the testes of intact and hypophysectomized Japanese quail","volume":"33","author":"Brown","year":"1977","journal-title":"Geneal Compar"},{"key":"2026042004060964500_bib23","doi-asserted-by":"publisher","first-page":"1337","DOI":"10.1098\/rspb.2001.1669","article-title":"Testosterone influences basal metabolic rate in male house sparrows: a new cost of dominance signalling?","volume":"268","author":"Buchanan","year":"2001","journal-title":"Proc R Soc B Biol Sci"},{"key":"2026042004060964500_bib24","doi-asserted-by":"publisher","first-page":"479","DOI":"10.1034\/j.1600-048X.2000.310407.x","article-title":"Testosterone does not affect basal metabolic rate or blood parasite load in captive male white-plumed Honeyeaters Lichenostomus penicillatus","volume":"31","author":"Buttemer","year":"2000","journal-title":"J Avian Biol"},{"key":"2026042004060964500_bib25","doi-asserted-by":"publisher","DOI":"10.1098\/rsbl.2022.0036","article-title":"No evidence of metabolic costs following adaptive immune activation or reactivation in house sparrows","volume":"18","author":"Buttemer","year":"2022","journal-title":"Biol Lett"},{"key":"2026042004060964500_bib26","doi-asserted-by":"publisher","first-page":"204","DOI":"10.1016\/j.cbpa.2006.06.047","article-title":"Testosterone effects on avian basal metabolic rate and aerobic performance: facts and artefacts","volume":"150","author":"Buttemer","year":"2008","journal-title":"Compar Biochem Physiol Mol Integr Physiol"},{"key":"2026042004060964500_bib27","doi-asserted-by":"publisher","first-page":"108321","DOI":"10.1016\/j.isci.2023.108321","article-title":"Mitochondrial metabolism in blood more reliably predicts whole-animal energy needs compared to other tissues","volume":"26","author":"Casagrande","year":"2023","journal-title":"iScience"},{"key":"2026042004060964500_bib28","doi-asserted-by":"publisher","first-page":"2269","DOI":"10.1242\/jeb.202.17.2269","article-title":"The relationship of central and peripheral organ masses to aerobic performance variation in house sparrows","volume":"202","author":"Chappell","year":"1999","journal-title":"J Exp Biol"},{"key":"2026042004060964500_bib29","doi-asserted-by":"publisher","first-page":"358","DOI":"10.1002\/jcb.20178","article-title":"Binding of MCF-7 cell mitochondrial proteins and recombinant human estrogen receptors \u03b1 and \u03b2 to human mitochondrial DNA estrogen response elements","volume":"93","author":"Chen","year":"2004","journal-title":"J Cell Biochem"},{"key":"2026042004060964500_bib30","doi-asserted-by":"publisher","first-page":"2362","DOI":"10.1139\/z87-357","article-title":"Sex and seasonal differences in metabolism in the red-sided garter snake, Thamnophis sirtalis parietalis","volume":"65","author":"Crews","year":"1987","journal-title":"Can J Zool"},{"key":"2026042004060964500_bib31","doi-asserted-by":"publisher","first-page":"94","DOI":"10.1016\/j.theriogenology.2017.02.015","article-title":"The relationship between mitochondrial DNA copy number and stallion sperm function","volume":"94","author":"Darr","year":"2017","journal-title":"Theriogenology"},{"key":"2026042004060964500_bib32","doi-asserted-by":"publisher","first-page":"365","DOI":"10.1177\/074873001129002079","article-title":"Photoperiodic control of seasonality in birds","volume":"16","author":"Dawson","year":"2001","journal-title":"J Biol Rhythms"},{"key":"2026042004060964500_bib33","doi-asserted-by":"publisher","first-page":"167","DOI":"10.1016\/j.ygcen.2005.12.024","article-title":"Testosterone induces testicular development but reduces GnRH-I fiber density in the brain of the House Finch, Carpodacus mexicanus","volume":"147","author":"Deviche","year":"2006","journal-title":"Gen Comp Endocrinol"},{"key":"2026042004060964500_bib2a","doi-asserted-by":"publisher","first-page":"2398","DOI":"10.1126\/science.1077780","article-title":"Rates of behavior and aging specified by mitochondrial function during development","volume":"298","author":"Dillin","year":"2002","journal-title":"Science"},{"key":"2026042004060964500_bib35","doi-asserted-by":"publisher","first-page":"67","DOI":"10.2307\/1539953","article-title":"A quantitative examination of ovarian growth in the white-crowned sparrow","volume":"130","author":"Farner","year":"1966","journal-title":"Biol Bull"},{"key":"2026042004060964500_bib36","doi-asserted-by":"publisher","first-page":"269","DOI":"10.1034\/j.1600-048X.2002.330309.x","article-title":"The natural plasma testosterone profile of male blue tits during the breeding season and its relation to song output","volume":"33","author":"Foerster","year":"2002","journal-title":"J Avian Biol"},{"key":"2026042004060964500_bib37","doi-asserted-by":"publisher","first-page":"66","DOI":"10.1016\/j.ygcen.2009.08.001","article-title":"Seasonal changes in androgen receptor mRNA in the brain of the white-crowned sparrow","volume":"166","author":"Fraley","year":"2010","journal-title":"Gen Comp Endocrinol"},{"key":"2026042004060964500_bib38","doi-asserted-by":"publisher","first-page":"111","DOI":"10.1007\/978-1-61779-998-3_9","article-title":"Analysis of DNA damage and repair in nuclear and mitochondrial DNA of animal cells using quantitative PCR","volume":"920","author":"Furda","year":"2012","journal-title":"Methods Mol Biol"},{"key":"2026042004060964500_bib3a","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1002\/jez.2871","article-title":"Experimentally elevated levels of testosterone advance daily onset of activity in short-day housed male house sparrows (Passer domesticus)","author":"Galante","year":"2024","journal-title":"J Exp Zool Part A Ecol Integr Physiol"},{"key":"2026042004060964500_bib40","doi-asserted-by":"publisher","first-page":"173","DOI":"10.1079\/bjn19820025","article-title":"The effects of physical exercise on metabolic rate and dietary-induced thermogenesis","volume":"47","author":"Gleeson","year":"1982","journal-title":"Br J Nutr"},{"key":"2026042004060964500_bib41","doi-asserted-by":"publisher","first-page":"1726","DOI":"10.1242\/jeb.085092","article-title":"An increase in minimum metabolic rate and not activity explains field metabolic rate changes in a breeding seabird","volume":"216","author":"Green","year":"2013","journal-title":"J Exp Biol"},{"key":"2026042004060964500_bib42","doi-asserted-by":"publisher","first-page":"113861","DOI":"10.1016\/j.ygcen.2021.113861","article-title":"Early nighttime testosterone peaks are correlated with GnRH-induced testosterone in a diurnal songbird","volume":"312","author":"Greives","year":"2021","journal-title":"Gen Comp Endocrinol"},{"key":"2026042004060964500_bib43","doi-asserted-by":"crossref","first-page":"1552","DOI":"10.1016\/S0021-9258(18)91795-3","article-title":"Apparent turnover of mitochondrial deoxyribonucleic acid and mitochondrial phospholipids in the tissues of the rat","volume":"244","author":"Gross","year":"1969","journal-title":"J Biol Chem"},{"key":"2026042004060964500_bib44","doi-asserted-by":"publisher","first-page":"66","DOI":"10.1016\/0016-6480(84)90062-5","article-title":"Role of thyroid and testicular hormones in the regulation of basal metabolic rate, gonad development, and body weight of spotted munia, Lonchura punctulata","volume":"56","author":"Gupta","year":"1984","journal-title":"Gen Comp Endocrinol"},{"key":"2026042004060964500_bib45","doi-asserted-by":"publisher","first-page":"211","DOI":"10.2307\/1934450","article-title":"The photorefractory period of the House Finch","volume":"49","author":"Hamner","year":"1968","journal-title":"Ecology"},{"key":"2026042004060964500_bib46","doi-asserted-by":"publisher","first-page":"509","DOI":"10.1007\/BF01922736","article-title":"The influence of the sex-hormone testosterone on body temperature and metabolism of the male Japanese quail (Coturnix coturnix japonica)","volume":"35","author":"Hanssler","year":"1979","journal-title":"Experientia"},{"key":"2026042004060964500_bib47","doi-asserted-by":"publisher","first-page":"224","DOI":"10.1086\/physzool.35.3.30152807","article-title":"Seasonal acclimatization in four species of small wild birds","volume":"35","author":"Hart","year":"1962","journal-title":"Physiol Zool"},{"key":"2026042004060964500_bib48","doi-asserted-by":"publisher","first-page":"165","DOI":"10.1016\/j.yhbeh.2004.02.007","article-title":"Testosterone reduces responsiveness to nociceptive stimuli in a wild bird","volume":"46","author":"Hau","year":"2004","journal-title":"Horm Behav"},{"key":"2026042004060964500_bib49","doi-asserted-by":"publisher","first-page":"1743","DOI":"10.1073\/pnas.1113306109","article-title":"Telomere length in early life predicts lifespan","volume":"109","author":"Heidinger","year":"2012","journal-title":"Proc Nat Acad Sci USA"},{"key":"2026042004060964500_bib50","doi-asserted-by":"publisher","first-page":"20210560","DOI":"10.1098\/rspb.2021.0560","article-title":"Longer telomeres during early life predict higher lifetime reproductive success in females but not males","volume":"288","author":"Heidinger","year":"2021","journal-title":"Proc R Soc B Biol Sci"},{"key":"2026042004060964500_bib51","doi-asserted-by":"publisher","first-page":"321","DOI":"10.1016\/0031-9384(84)90119-7","article-title":"Dietary obesity and exercise in young rats","volume":"33","author":"Hill","year":"1984","journal-title":"Physiol Behav"},{"key":"2026042004060964500_bib52","doi-asserted-by":"publisher","first-page":"R433","DOI":"10.1152\/ajpregu.00179.2002","article-title":"Artificial selection for high activity favors mighty mini-muscles in house mice","volume":"284","author":"Houle-leroy","year":"2003","journal-title":"Am J Physiol-Regul Integr Comp Physiol"},{"key":"2026042004060964500_bib53","doi-asserted-by":"publisher","first-page":"203","DOI":"10.1016\/0010-406X(66)90021-1","article-title":"Temperature regulation and metabolic rhythms in populations of the house sparrow, Passer domesticus","volume-title":"Comp Biochem Physiol","author":"Hudson","year":"1966"},{"key":"2026042004060964500_bib54","doi-asserted-by":"publisher","first-page":"869","DOI":"10.1086\/422768","article-title":"Basal metabolic rate: history, composition, regulation, and usefulness A brief history of Basal metabolic rate: from where did BMR come?","volume":"77","author":"Hulbert","year":"2004","journal-title":"Physiol Biochem Zool"},{"key":"2026042004060964500_bib55","doi-asserted-by":"publisher","first-page":"23","DOI":"10.1016\/S0047-6374(99)00093-7","article-title":"Effects of long-term, light exercise under restricted feeding on age-related changes in physiological and metabolic variables in male Wistar rats","volume":"113","author":"Ichikawa","year":"2000","journal-title":"Mech Ageing Dev"},{"key":"2026042004060964500_bib56","doi-asserted-by":"publisher","first-page":"1402","DOI":"10.1096\/fj.10-169029","article-title":"Tamoxifen increases nuclear respiratory factor 1 transcription by activating estrogen receptor \u03b2 and AP-1 recruitment to adjacent promoter binding sites","volume":"25","author":"Ivanova","year":"2011","journal-title":"FASEB J"},{"key":"2026042004060964500_bib57","doi-asserted-by":"publisher","first-page":"762","DOI":"10.1086\/676933","article-title":"Experimental sources of variation in avian energetics: estimated basal metabolic rate decreases with successive measurements","volume":"87","author":"Jacobs","year":"2014","journal-title":"Physiol Biochem Zool"},{"key":"2026042004060964500_bib58","doi-asserted-by":"publisher","first-page":"602","DOI":"10.1139\/Z2012-026","article-title":"Variation in basal metabolic rate and activity in relation to reproductive condition and photoperiod in white-footed mice (Peromyscus leucopus)","volume":"90","author":"Kaseloo","year":"2012","journal-title":"Can J Zool"},{"key":"2026042004060964500_bib59","first-page":"12","article-title":"Energy responses of birds to their thermal environments","volume":"81","author":"Kendeigh","year":"1969","journal-title":"Wilson Bulletin"},{"key":"2026042004060964500_bib59a","doi-asserted-by":"publisher","first-page":"182","DOI":"10.1016\/j.cbpa.2008.09.011","article-title":"Seasonal metabolic changes in a year-round reproductively active subtropical tree-frog (Hypsiboas prasinus)","volume":"152","author":"Kiss","year":"2009","journal-title":"Comparative Biochemistry and Physiology\u2014A Molecular and Integrative Physiology"},{"key":"2026042004060964500_bib60","doi-asserted-by":"publisher","first-page":"195","DOI":"10.1002\/jez.2557","article-title":"The positive relationship between androgens and hematocrit levels in the Japanese quail (Coturnix japonica)","volume":"337","author":"Kobayashi","year":"2022","journal-title":"J Exp Zool Part A Ecol Integr Physiol"},{"key":"2026042004060964500_bib61","doi-asserted-by":"publisher","first-page":"321","DOI":"10.1016\/j.tree.2020.12.006","article-title":"Integrating mitochondrial aerobic metabolism into ecology and evolution","volume":"36","author":"Koch","year":"2021","journal-title":"Trends Ecol Evol"},{"key":"2026042004060964500_bib63","doi-asserted-by":"publisher","first-page":"64","DOI":"10.1016\/0016-6480(87)90061-X","article-title":"Annual reproductive cycle in the male red-sided garter snake, thamnophis sirtalis parietalis: field and Laboratory Studies","volume":"68","author":"Krohmer","year":"1987","journal-title":"Gen Comp Endocrinol"},{"key":"2026042004060964500_bib64","doi-asserted-by":"publisher","first-page":"1","DOI":"10.18637\/jss.v069.i01","article-title":"Least-squares means: the R package lsmeans","volume":"69","author":"Lenth","year":"2016","journal-title":"J Stat Softw"},{"key":"2026042004060964500_bib65","article-title":"_emmeans: estimated Marginal means, aka least-Squares means_","author":"Lenth","year":"2023"},{"key":"2026042004060964500_bib66","first-page":"99","article-title":"Seasonal changes in the hypothalamo-pituitary-gonadal axis in birds","volume":"7","author":"Leska","year":"2007","journal-title":"Reprod Biol"},{"key":"2026042004060964500_bib67","doi-asserted-by":"publisher","first-page":"63","DOI":"10.1016\/j.ygcen.2012.07.026","article-title":"Seasonal changes in the expression of the androgen receptor in the testes of the domestic goose (Anser anser f. domestica)","volume":"179","author":"Leska","year":"2012","journal-title":"Gen Comp Endocrinol"},{"key":"2026042004060964500_bib68","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1186\/s40657-020-00222-9","article-title":"Thermogenic responses in Eurasian Tree Sparrow (Passer montanus) to seasonal acclimatization and temperature-photoperiod acclimation","volume":"11","author":"Li","year":"2020","journal-title":"Avian Res"},{"key":"2026042004060964500_bib69","doi-asserted-by":"crossref","DOI":"10.1093\/acprof:oso\/9780195310610.001.0001","volume-title":"Measuring metabolic rates: a manual for scientists","author":"Lighton","year":"2008"},{"key":"2026042004060964500_bib70","first-page":"5","article-title":"Captivity affects sperm production, testes size and beak color in House Sparrows, (Passer domesticus)","volume":"33","author":"Lombardo","year":"2009","journal-title":"Int Stud Sparrows"},{"key":"2026042004060964500_bib71","doi-asserted-by":"publisher","first-page":"3139","DOI":"10.21105\/joss.03139","article-title":"performance: an R package for assessment, comparison and testing of statistical models","volume":"6","author":"L\u00fcdecke","year":"2021","journal-title":"J Open Source Softw"},{"key":"2026042004060964500_bib72","doi-asserted-by":"publisher","first-page":"691633","DOI":"10.3389\/fphys.2021.691633","article-title":"Inferring whole-organism metabolic rate from red blood cells in birds","volume":"12","author":"Malkoc","year":"2021","journal-title":"Front Physiol"},{"key":"2026042004060964500_bib73","doi-asserted-by":"publisher","first-page":"153","DOI":"10.1098\/rspb.2002.2185","article-title":"Immune activity elevates energy expenditure of house sparrows: a link between direct and indirect costs?","volume":"270","author":"Martin","year":"2003","journal-title":"Proc R Soc B Biol Sci"},{"key":"2026042004060964500_bib74","doi-asserted-by":"publisher","first-page":"223","DOI":"10.1677\/joe.0.0840223","article-title":"Cloacal Gland of the Japanese quail: androgen dependence and metabolism of testosterone","volume":"84","author":"Massa","year":"1980","journal-title":"J Endocrinol"},{"key":"2026042004060964500_bib75","doi-asserted-by":"publisher","first-page":"609","DOI":"10.1210\/me.2007-0029","article-title":"Estradiol stimulates transcription of nuclear respiratory factor-1 and increases mitochondrial biogenesis","volume":"22","author":"Mattingly","year":"2008","journal-title":"Mol Endocrinol"},{"key":"2026042004060964500_bib76","doi-asserted-by":"publisher","first-page":"456","DOI":"10.1002\/jez.2312","article-title":"Testosterone does not mediate variation in basal metabolic rate and activity in relation to reproductive condition and photoperiod in white-footed mice (Peromyscus leucopus)","volume":"331","author":"McDonnell","year":"2019","journal-title":"J Exp Zool Part A Ecol Integr Physiol"},{"key":"2026042004060964500_bib77","doi-asserted-by":"publisher","first-page":"367","DOI":"10.1007\/s10336-015-1186-5","article-title":"Global patterns of seasonal acclimatization in avian resting metabolic rates","volume":"156","author":"McKechnie","year":"2015","journal-title":"J Ornithol"},{"key":"2026042004060964500_bib78","doi-asserted-by":"publisher","first-page":"741","DOI":"10.1093\/czoolo\/56.6.741","article-title":"Sources and significance of variation in basal, summit and maximal metabolic rates in birds","volume":"56","author":"Mckechnie","year":"2010","journal-title":"Curr Zool"},{"key":"2026042004060964500_bib79","doi-asserted-by":"publisher","first-page":"362","DOI":"10.1086\/639616","article-title":"Basal metabolic rate in relation to body composition and daily energy expenditure in the field vole, microtus agrestis","volume":"70","author":"Meerlo","year":"1997","journal-title":"Physiol Zool"},{"key":"2026042004060964500_bib80","doi-asserted-by":"publisher","first-page":"534","DOI":"10.1093\/gerona\/61.6.534","article-title":"Effects of exercise on mitochondrial content and function in aging human skeletal muscle","volume":"61","author":"Menshikova","year":"2006","journal-title":"J Gerontol Ser A Biol Sci Med Sci"},{"key":"2026042004060964500_bib81","doi-asserted-by":"publisher","first-page":"R1321","DOI":"10.1152\/ajpregu.2000.279.4.R1321","article-title":"Treadmill running produces both positive and negative physiological adaptations in Sprague-Dawley rats","volume":"279","author":"Moraska","year":"2000","journal-title":"Am J Physiol-Regul Integr Comp Physiol"},{"key":"2026042004060964500_bib82","doi-asserted-by":"publisher","first-page":"404","DOI":"10.1111\/j.2007.0908-8857.03863.x","article-title":"An allometric function to fit leg-loop harnesses to terrestrial birds","volume":"38","author":"Naef-Daenzer","year":"2007","journal-title":"J Avian Biol"},{"key":"2026042004060964500_bib83","doi-asserted-by":"publisher","first-page":"211","DOI":"10.1016\/j.ygcen.2016.12.010","article-title":"Consistent individual variation in day, night, and GnRH-induced testosterone concentrations in house sparrows (Passer domesticus)","volume":"246","author":"Needham","year":"2016","journal-title":"Gen Comp Endocrinol"},{"key":"2026042004060964500_bib84","doi-asserted-by":"publisher","first-page":"3877","DOI":"10.1242\/jeb.013110","article-title":"Whole-animal metabolic rate is a repeatable trait: a meta-analysis","volume":"210","author":"Nespolo","year":"2007","journal-title":"J Exp Biol"},{"key":"2026042004060964500_bib85","doi-asserted-by":"publisher","first-page":"187","DOI":"10.1007\/s004420100653","article-title":"The resting metabolic cost of egg laying and nestling feeding in great tits","volume":"128","author":"Nilsson","year":"2001","journal-title":"Oecologia"},{"key":"2026042004060964500_bib86","doi-asserted-by":"publisher","first-page":"1789","DOI":"10.1016\/s0163-1047(87)90327-x","article-title":"Seasonal changes in gonadal hormone levels of adult male canaries and their relation to song songbirds sing to defend a territory and charm a mate","volume":"47","author":"Nottebohm","year":"1987","journal-title":"Behav Neural Biol"},{"key":"2026042004060964500_bib87","doi-asserted-by":"publisher","first-page":"100","DOI":"10.1016\/j.jtherbio.2009.12.002","article-title":"Seasonal variation in the metabolism-temperature relation of House Sparrows (Passer domesticus) in KwaZulu-Natal, South Africa","volume":"35","author":"Nzama","year":"2010","journal-title":"J Therm Biol"},{"key":"2026042004060964500_bib88","doi-asserted-by":"publisher","first-page":"jeb246717","DOI":"10.1242\/jeb.246717","article-title":"What makes a great invader? Anatomical traits as predictors of locomotor performance and metabolic rate in an invasive frog","volume":"226","author":"Padilla","year":"2023","journal-title":"J Exp Biol"},{"key":"2026042004060964500_bib89","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1371\/journal.pone.0068292","article-title":"Intra-seasonal flexibility in avian metabolic performance highlights the uncoupling of basal metabolic rate and thermogenic capacity","volume":"8","author":"Petit","year":"2013","journal-title":"PLoS One"},{"key":"2026042004060964500_bib90","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1016\/j.mito.2021.06.010","article-title":"Blood mitochondrial DNA copy number: what are we counting?","volume":"60","author":"Picard","year":"2021","journal-title":"Mitochondrion"},{"key":"2026042004060964500_bib91","doi-asserted-by":"publisher","first-page":"37","DOI":"10.1007\/BF00264684","article-title":"Seasonality in basal metabolic rate and thermal conductance in a long-distance migrant shorebird, the knot (Calidris canutus)","volume":"165","author":"Piersma","year":"1995","journal-title":"J Compar Physiol B"},{"key":"2026042004060964500_bib92","first-page":"105","article-title":"Exercise induced changes in the energy expenditure of female Wistar rats","volume":"33","author":"Pinto","year":"1995","journal-title":"Indian J Exp Biol"},{"key":"2026042004060964500_bib93","doi-asserted-by":"publisher","first-page":"531","DOI":"10.1016\/j.anbehav.2005.10.022","article-title":"Early birds are sexy: male age, dawn song and extrapair paternity in blue tits, Cyanistes (formerly Parus) caeruleus","volume":"72","author":"Poesel","year":"2006","journal-title":"Anim Behav"},{"key":"2026042004060964500_bib94","doi-asserted-by":"publisher","first-page":"511","DOI":"10.1159\/000125636","article-title":"Influence of photoinhibition, photostimulation and prolactin on pituitary and hypothalamic nuclear androgen receptors in the male hamster","volume":"52","author":"Prins","year":"1990","journal-title":"Neuroendocrinology"},{"key":"2026042004060964500_bib95","doi-asserted-by":"publisher","first-page":"216.e7","DOI":"10.1016\/j.neurobiolaging.2015.10.033","article-title":"Reduced mitochondrial DNA copy number is a biomarker of Parkinson\u2019s disease","volume":"38","author":"Pyle","year":"2015","journal-title":"Neurobiol Aging"},{"key":"2026042004060964500_bib96","volume-title":"R: a Language and Environment for Statistical Computing (Version 4.2.2)","author":"R Core Team","year":"2022"},{"key":"2026042004060964500_bib97","doi-asserted-by":"publisher","first-page":"59","DOI":"10.1007\/s10863-008-9130-5","article-title":"Influence of mitochondrial DNA level on cellular energy metabolism: implications for mitochondrial diseases","volume":"40","author":"Rocher","year":"2008","journal-title":"J Bioenerg Biomembr"},{"key":"2026042004060964500_bib98","doi-asserted-by":"publisher","first-page":"4663","DOI":"10.1242\/jeb.01941","article-title":"Long-term repeatability makes basal metabolic rate a likely heritable trait in the zebra finch Taeniopygia guttata","volume":"208","author":"R\u00f8nning","year":"2005","journal-title":"J Exp Biol"},{"key":"2026042004060964500_bib99","doi-asserted-by":"publisher","first-page":"895","DOI":"10.1111\/j.1095-8649.2004.00484.x","article-title":"Androgen levels and energy metabolism in Oreochromis mossambicus","volume":"65","author":"Ros","year":"2004","journal-title":"J Fish Biol"},{"key":"2026042004060964500_bib100","doi-asserted-by":"publisher","first-page":"20122576","DOI":"10.1098\/rspb.2012.2576","article-title":"Basal metabolic rate is positively correlated with parental investment in laboratory mice","volume":"280","author":"Sadowska","year":"2013","journal-title":"Proc R Soc B"},{"key":"2026042004060964500_bib101","doi-asserted-by":"publisher","first-page":"75","DOI":"10.1016\/j.mito.2017.02.001","article-title":"Mitochondrial genotype modulates mtDNA copy number and organismal phenotype in Drosophila","volume":"34","author":"Salminen","year":"2017","journal-title":"Mitochondrion"},{"key":"2026042004060964500_bib102","doi-asserted-by":"publisher","first-page":"5618","DOI":"10.1073\/pnas.0501559102","article-title":"Decline in skeletal muscle mitochondrial function with aging in humans","volume":"102","author":"Short","year":"2005","journal-title":"Proc Nat Acad Sci USA"},{"key":"2026042004060964500_bib103","doi-asserted-by":"publisher","first-page":"110","DOI":"10.1159\/000437412","article-title":"Testosterone mediates seasonal growth of the song control nuclei in a tropical bird","volume":"86","author":"Small","year":"2015","journal-title":"Brain Behav Evol"},{"key":"2026042004060964500_bib104","doi-asserted-by":"publisher","first-page":"483","DOI":"10.1016\/j.yhbeh.2007.01.004","article-title":"Environmental regulation of the reproductive system in a flexibly breeding Sonoran Desert bird, the Rufous-winged Sparrow, Aimophila carpalis","volume":"51","author":"Small","year":"2007","journal-title":"Horm Behav"},{"key":"2026042004060964500_bib105","doi-asserted-by":"publisher","first-page":"330","DOI":"10.1111\/j.1365-2435.2009.01646.x","article-title":"Avian seasonal metabolic variation in a subtropical desert: basal metabolic rates are lower in winter than in summer","volume":"24","author":"Smit","year":"2010","journal-title":"Funct Ecol"},{"key":"2026042004060964500_bib7a","doi-asserted-by":"crossref","first-page":"114","DOI":"10.1002\/neu.480280110","article-title":"Seasonal changes in song nuclei and song behavior in Gambel\u2019s white-crowned sparrows","volume":"28","author":"Smith","year":"1995","journal-title":"J Neurobiol"},{"key":"2026042004060964500_bib106","doi-asserted-by":"publisher","first-page":"426","DOI":"10.1002\/(SICI)1097-4695(199704)32:4&lt;426::AID-NEU6&gt;3.0.CO;2-8","article-title":"Roles of photoperiod and testosterone in seasonal plasticity of the avian song control system","volume":"32","author":"Smith","year":"1997","journal-title":"J Neurobiol"},{"key":"2026042004060964500_bib107","doi-asserted-by":"publisher","first-page":"224","DOI":"10.1002\/(SICI)1096-9861(19990628)409:2&lt;224::AID-CNE4&gt;3.0.CO;2-V","article-title":"Seasonal changes in androgen receptor immunoreactivity in the song nucleus HVc of a wild bird","volume":"409","author":"Soma","year":"1999","journal-title":"J Comp Neurol"},{"key":"2026042004060964500_bib108","doi-asserted-by":"publisher","first-page":"621","DOI":"10.1079\/pns2003282","article-title":"Physical activity and resting metabolic rate","volume":"62","author":"Speakman","year":"2003","journal-title":"Proc Nutr Soc"},{"key":"2026042004060964500_bib109","doi-asserted-by":"publisher","first-page":"20","DOI":"10.1111\/j.1600-079X.1992.tb00050.x","article-title":"Regulation of the androgen receptors in the harderian gland of the male Syrian hamster: influence of photoperiod, castration, and chronic melatonin treatment","volume":"13","author":"Stankov","year":"1992","journal-title":"J Pineal Res"},{"key":"2026042004060964500_bib110","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1016\/j.ygcen.2012.03.013","article-title":"Variation in the gonadotrophin-releasing hormone-1 and the song control system in the tropical breeding rufous-collared sparrow (Zonotrichia capensis) is dependent on sex and reproductive state","volume":"178","author":"Stevenson","year":"2012","journal-title":"Gen Comp Endocrinol"},{"key":"2026042004060964500_bib111","doi-asserted-by":"publisher","first-page":"20190536","DOI":"10.1098\/rsbl.2019.0536","article-title":"Plastic but repeatable: rapid adjustments of mitochondrial function and density during reproduction in a wild bird species","volume":"15","author":"Stier","year":"2019","journal-title":"Biol Lett"},{"key":"2026042004060964500_bib112","doi-asserted-by":"publisher","first-page":"1172","DOI":"10.1111\/2041-210X.12724","article-title":"How to measure mitochondrial function in birds using red blood cells: a case study in the king penguin and perspectives in ecology and evolution","volume":"8","author":"Stier","year":"2017","journal-title":"Methods Ecol Evol"},{"key":"2026042004060964500_bib113","doi-asserted-by":"publisher","first-page":"1639","DOI":"10.1111\/2041-210X.12797","article-title":"rptR: repeatability estimation and variance decomposition by generalized linear mixed-effects models","volume":"8","author":"Stoffel","year":"2017","journal-title":"Methods Ecol Evol"},{"key":"2026042004060964500_bib114","doi-asserted-by":"publisher","first-page":"654","DOI":"10.1016\/j.molcel.2016.01.028","article-title":"The mitochondrial basis of aging","volume":"61","author":"Sun","year":"2016","journal-title":"Mol Cell"},{"key":"2026042004060964500_bib115","doi-asserted-by":"publisher","first-page":"75","DOI":"10.1007\/978-1-4419-6421-2_3","article-title":"Seasonal metabolic variation in birds: functional and mechanistic correlates","volume-title":"Current ornithology","author":"Swanson","year":"2010"},{"key":"2026042004060964500_bib116","doi-asserted-by":"publisher","first-page":"16302","DOI":"10.1074\/jbc.M001364200","article-title":"Modulation of estrogen receptor-\u03b1 transcriptional activity by the coactivator PGC-1","volume":"275","author":"Tcherepanova","year":"2000","journal-title":"J Biol Chem"},{"key":"2026042004060964500_bib117","doi-asserted-by":"publisher","first-page":"79","DOI":"10.1016\/j.molbrainres.2004.08.009","article-title":"Photoperiodic regulation of androgen receptor and steroid receptor coactivator-1 in Siberian hamster brain","volume":"131","author":"Tetel","year":"2004","journal-title":"Mol Brain Res"},{"key":"2026042004060964500_bib118","doi-asserted-by":"publisher","first-page":"898","DOI":"10.1095\/biolreprod56.4.898","article-title":"Photoperiod-induced changes in androgen receptor expression in testes and accessory sex glands of the bank vole, Clethrionomys glareolus","volume":"56","author":"Thaka","year":"1997","journal-title":"Biol Reprod"},{"key":"2026042004060964500_bib119","doi-asserted-by":"publisher","first-page":"444","DOI":"10.1016\/0016-6480(83)90061-8","article-title":"Thyroid and gonad in the oxidative metabolism, erythropoiesis, and light response of the migratory redheaded bunting, Emberiza bruniceps","volume":"51","author":"Thapliyal","year":"1983","journal-title":"Gen Comp Endocrinol"},{"key":"2026042004060964500_bib8a","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1007\/BF00004671","article-title":"Seasonal variation of muscle metabolic organization in rainbow trout (Oncorhynchus mykiss)","volume":"16","author":"Thibault","year":"1997","journal-title":"Fish Physiol Biochem"},{"key":"2026042004060964500_bib120","doi-asserted-by":"publisher","first-page":"bio060302","DOI":"10.1242\/bio.060302","article-title":"The relationship between mitochondrial respiration, resting metabolic rate and blood cell count in great tits","volume":"13","author":"Thoral","year":"2024","journal-title":"Biol Open"},{"key":"2026042004060964500_bib121","doi-asserted-by":"publisher","first-page":"563","DOI":"10.2307\/2389916","article-title":"Parental energy expenditure during brood rearing in the great tit (Parus major) in relation to body mass, temperature, food availability and clutch size","volume":"8","author":"Tinbergen","year":"1994","journal-title":"Ecology"},{"key":"2026042004060964500_bib122","doi-asserted-by":"publisher","first-page":"241","DOI":"10.1111\/evo.12260","article-title":"Migration, mitochondria, and the yellow-rumped warbler","volume":"68","author":"Toews","year":"2014","journal-title":"Evolution"},{"key":"2026042004060964500_bib123","doi-asserted-by":"publisher","DOI":"10.1186\/1742-9994-3-12","article-title":"Control of annual reproductive cycle in the subtropical house sparrow (Passer domesticus): evidence for conservation of photoperiodic control mechanisms in birds","volume":"3","author":"Trivedi","year":"2006","journal-title":"Front Zool"},{"key":"2026042004060964500_bib124","doi-asserted-by":"publisher","first-page":"e97334","DOI":"10.1371\/journal.pone.0097334","article-title":"Seasonal changes in plasma levels of sex hormones in the Greater Rhea (Rhea americana), a South American ratite with a complex mating system","volume":"9","author":"Valdez","year":"2014","journal-title":"PLoS One"},{"key":"2026042004060964500_bib125","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1038\/s41598-019-38535-5","article-title":"Redox-regulation and life-history trade-offs: scavenging mitochondrial ROS improves growth in a wild bird","volume":"9","author":"Velando","year":"2019","journal-title":"Sci Rep"},{"key":"2026042004060964500_bib126","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1186\/2046-2395-3-2","article-title":"Mitochondrial and sex steroid hormone crosstalk during aging","volume":"3","author":"Velarde","year":"2014","journal-title":"Longevity Healthspan"},{"key":"2026042004060964500_bib127","doi-asserted-by":"publisher","first-page":"452","DOI":"10.1016\/j.cbpa.2008.05.006","article-title":"Repeatability and individual correlates of basal metabolic rate and total evaporative water loss in birds: a case study in European stonechats","volume":"150","author":"Versteegh","year":"2008","journal-title":"Compar Biochem Physiol A Mol Integr Physiol"},{"key":"2026042004060964500_bib128","doi-asserted-by":"publisher","first-page":"716","DOI":"10.1086\/376425","article-title":"Plasticity in body composition in breeding birds: what drives the metabolic costs of egg production?","volume":"76","author":"V\u00e9zina","year":"2003","journal-title":"Physiol Biochem Zool"},{"key":"2026042004060964500_bib129","doi-asserted-by":"publisher","first-page":"186","DOI":"10.33594\/000000129","article-title":"Functional estrogen receptors of red blood cells. Do they influence intracellular signaling?","volume":"53","author":"Vona","year":"2019","journal-title":"Cell Physiol Biochem"},{"key":"2026042004060964500_bib130","doi-asserted-by":"publisher","first-page":"511","DOI":"10.1086\/physzool.66.4.30163806","article-title":"Seasonal patterns of time and energy allocation by birds","volume":"66","author":"Weathers","year":"1993","journal-title":"Physiol Zool"},{"key":"2026042004060964500_bib131","doi-asserted-by":"publisher","first-page":"481","DOI":"10.1111\/j.1600-048X.2012.05709.x","article-title":"Seasonality of peak metabolic rate in non-migrant tropical birds","volume":"43","author":"Wells","year":"2012","journal-title":"J Avian Biol"},{"key":"2026042004060964500_bib132","doi-asserted-by":"publisher","first-page":"463","DOI":"10.1007\/s003590050407","article-title":"Energy metabolism, testosterone and corticosterone in white-crowned sparrows","volume":"185","author":"Wikelski","year":"1999","journal-title":"J Compar Physiol"},{"key":"2026042004060964500_bib133","doi-asserted-by":"crossref","first-page":"376","DOI":"10.1016\/S0021-9258(17)42482-3","article-title":"Regulation of nuclear and mitochondrial gene expression by contractile activity in skeletal muscle","volume":"261","author":"Williams","year":"1986","journal-title":"J Biol Chem"},{"key":"2026042004060964500_bib134","first-page":"139","article-title":"Changes in body composition and daily energy expenditure induced in rats during eight weeks of daily swim training","volume":"17","author":"Wilterdink","year":"1993","journal-title":"Int J Obesity Related Metab Disorders J Int Assoc Study Obesity"},{"key":"2026042004060964500_bib135","doi-asserted-by":"publisher","first-page":"570","DOI":"10.2307\/1367117","article-title":"Avian endocrinology: field investigations and methods","volume":"78","author":"Wingfield","year":"1976","journal-title":"Condor"},{"key":"2026042004060964500_bib136","doi-asserted-by":"publisher","first-page":"829","DOI":"10.1086\/285134","article-title":"The \u201cchallenge hypothesis\u201d: theoretical implications for patterns of testosterone secretion, mating systems, and breeding strategies","volume":"136","author":"Wingfield","year":"1990","journal-title":"Am Nat"}],"container-title":["Integrative Organismal Biology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/academic.oup.com\/iob\/advance-article-pdf\/doi\/10.1093\/iob\/obag013\/67725545\/obag013.pdf","content-type":"application\/pdf","content-version":"am","intended-application":"syndication"},{"URL":"https:\/\/academic.oup.com\/iob\/article-pdf\/8\/1\/obag013\/67725545\/obag013.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/academic.oup.com\/iob\/article-pdf\/8\/1\/obag013\/67725545\/obag013.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,20]],"date-time":"2026-04-20T08:06:26Z","timestamp":1776672386000},"score":1,"resource":{"primary":{"URL":"https:\/\/academic.oup.com\/iob\/article\/doi\/10.1093\/iob\/obag013\/8572519"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026]]},"references-count":137,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2026,1,14]]}},"URL":"https:\/\/doi.org\/10.1093\/iob\/obag013","relation":{},"ISSN":["2517-4843"],"issn-type":[{"value":"2517-4843","type":"electronic"}],"subject":[],"published-other":{"date-parts":[[2026]]},"published":{"date-parts":[[2026]]},"article-number":"obag013"}}