Editing Sexual selection (section)

=== In birds ===
{{Main |Sexual selection in birds}}

Birds have evolved a wide variety of mating behaviours and many types of sexual selection. These include intersexual selection (female choice) and intrasexual competition, where individuals of the more abundant sex compete with each other for the privilege to mate. Many species, notably the [[Bird-of-paradise|birds-of-paradise]], are sexually dimorphic; the differences such as in size and coloration are energetically costly attributes that signal competitive breeding. Conflicts between an individual's fitness and signalling adaptations ensure that sexually selected ornaments such as coloration of plumage and courtship behaviour are [[honest signal|honest]] traits. Signals must be costly to ensure that only good-quality individuals can present these exaggerated sexual ornaments and behaviours. Males with the brightest plumage are favoured by females of multiple species of bird.<ref name=saino2013>{{cite journal|last=Saino|first=Nicola|author2=Romano, Maria |author3=Rubolini, Diego |author4=Teplitsky, Celine |author5=Ambrosini, Roberto |author6=Caprioli, Manuela |author7=Canova, Luca |author8=Wakamatsu, Kazumasa |author9=Roulin, Alexandre |display-authors=3 |title=Sexual Dimorphism in Melanin Pigmentation, Feather Coloration and Its Heritability in the Barn Swallow (Hirundo rustica) |journal=PLOS ONE |year=2013 |volume=8 |issue=2 |pages=e58024 |doi=10.1371/journal.pone.0058024 |pmid=23469134 |pmc=3585210 |bibcode=2013PLoSO...858024S|doi-access=free}}</ref><ref name=edwards2012>{{cite journal |last=Edwards |first=D.B. |title=Immune investment is explained by sexual selection and pace-of-life, but not longevity in parrots (Psittaciformes) |journal=PLOS ONE |year=2012 |volume=7 |issue=12 |pages=e53066 |pmid=23300862 |doi=10.1371/journal.pone.0053066 |pmc=3531452 |bibcode=2012PLoSO...753066E |doi-access=free }}</ref><ref name="Doutrelant 2012">{{cite journal |last1=Doutrelant |first1=C. |last2=Grégoire |first2=A. |last3=Midamegbe |first3=A. |last4=Lambrechts |first4=M. |last5=Perret |first5=P. |title=Female plumage coloration is sensitive to the cost of reproduction. An experiment in blue tits |journal=[[Journal of Animal Ecology]] |date=January 2012 |volume=81 |issue=1 |pages=87–96 |pmid=21819397 |doi=10.1111/j.1365-2656.2011.01889.x |doi-access=free|bibcode=2012JAnEc..81...87D }}</ref>

Many bird species make use of [[mating call]]s, the females preferring [[Bird vocalization|males with songs]] that are complex and varied in amplitude, structure, and frequency. Larger males have deeper songs and increased mating success.<ref>{{cite journal |last=Hall |first=L. |author2=Kingma, S. A. |author3=Peters, A. |title=Male songbird indicates body size with low-pitched advertising songs |journal=PLOS ONE |year=2013 |volume=8 |issue=2 |pages=e56717 |pmid=23437221 |doi=10.1371/journal.pone.0056717 |pmc=3577745 |bibcode=2013PLoSO...856717H |doi-access=free}}</ref><ref name="Pfaff 2007">{{cite journal |last=Pfaff |first=J. A. |author2=Zanette, L. |author3=MacDougall-Shackleton, S. A. |author4=MacDougall-Shackleton, E. A. |title=Song repertoire size varies with HVC volume and is indicative of male quality in song sparrows (Melospiza melodia) |journal=[[Proceedings of the Royal Society B]] |date=22 August 2007 |volume=274 |issue=1621 |pages=2035–40 |pmid=17567560 |doi=10.1098/rspb.2007.0170 |pmc=2275172}}</ref><ref name="Nemeth 2012">{{cite journal |last=Nemeth |first=E. |author2=Kempenaers, B. |author3=Matessi, G. |author4=Brumm, H. |title=Rock sparrow song reflects male age and reproductive success |journal=PLOS ONE |year=2012 |volume=7 |issue=8 |pages=e43259 |pmid=22927955 |doi=10.1371/journal.pone.0043259 |pmc=3426517 |bibcode=2012PLoSO...743259N |doi-access=free}}</ref><ref>{{cite journal |author1= Mikula, P. |author2= Valcu, M. | author3= Brumm, H. | author4= Bulla, M. | author5= Forstmeier, W. | author6= Petrusková, T. | author7= Kempenaers, B. | author8= Albrecht, T | year=2021| title= A global analysis of song frequency in passerines provides no support for the acoustic adaptation hypothesis but suggests a role for sexual selection. | journal= Ecology Letters | volume= 24 | issue = 3 | pages= 477–486|doi=10.1111/ele.13662|pmid= 33314573|s2cid= 229176172 | doi-access= free |bibcode= 2021EcolL..24..477M }}</ref>{{Clear}}