▁to ▁reproduce , ▁causing ▁the ▁population ▁to ▁have ▁a ▁female ▁bi ased ▁OS R . ▁Another ▁example ▁would ▁be ▁if , ▁in ▁a ▁certain ▁species , ▁males ▁provided ▁care ▁for ▁off spring ▁and ▁a ▁nest . ▁If ▁the ▁avail ability ▁of ▁nest ing ▁sites ▁decre ased , ▁we ▁would ▁see ▁the ▁population ▁tr end ▁towards ▁a ▁more ▁female ▁bi ased ▁OS R ▁because ▁only ▁a ▁small ▁number ▁of ▁males ▁actually ▁have ▁a ▁nest ▁while ▁all ▁the ▁females , ▁regardless ▁of ▁a ▁nest ▁or ▁not , ▁are ▁still ▁producing ▁eggs . ▁ ▁Some ▁factors ▁that ▁OS R ▁predict s ▁A ▁major ▁factor ▁that ▁OS R ▁can ▁predict ▁is ▁the ▁opportunity ▁for ▁sexual ▁selection . ▁As ▁the ▁OS R ▁becomes ▁more ▁bi ased , ▁the ▁sex ▁that ▁is ▁in ▁excess ▁will ▁tend ▁to ▁under go ▁more ▁competition ▁for ▁m ates ▁and ▁therefore ▁under go ▁strong ▁sexual ▁selection . ▁Int ens ity ▁of ▁competition ▁is ▁also ▁a ▁factor ▁that ▁can ▁be ▁predicted ▁by ▁OS R . ▁According ▁to ▁sexual ▁selection ▁theory , ▁wh iche ver ▁sex ▁is ▁more ▁abund ant ▁is ▁expected ▁to ▁comp ete ▁more ▁strongly ▁and ▁the ▁sex ▁that ▁is ▁less ▁abund ant ▁is ▁expected ▁to ▁be ▁" cho os ier " ▁in ▁who ▁they ▁decide ▁to ▁mate ▁with . ▁It ▁would ▁be ▁expected ▁that ▁when ▁an ▁OS R ▁is ▁more ▁bi ased ▁to ▁one ▁sex ▁than ▁the ▁other , ▁that ▁one ▁would ▁observe ▁more ▁interaction ▁and ▁competition ▁from ▁the ▁sex ▁that ▁is ▁more ▁available ▁to ▁mate . ▁When ▁the ▁population ▁is ▁more ▁female