▁that ▁are ▁found ▁in ▁the ▁South ▁Hills ▁and ▁Alb ion ▁Mountains ▁region . ▁A ▁primary ▁reason ▁why ▁this ▁species ▁of ▁cross b ill ▁can ▁exist ▁in ▁such ▁a ▁small ▁area ▁and ▁on ▁a ▁singular ▁food ▁source ▁is ▁due ▁to ▁the ▁lack ▁of ▁squ ir rel s , ▁the ▁usual ▁primary ▁seed ▁dispers al ▁of ▁the ▁l odge pole ▁p ine . ▁As ▁a ▁result , ▁ser ot in ous ▁con es ▁are ▁especially ▁abund ant ▁in ▁this ▁region , ▁which ▁allows ▁con es ▁with ▁se eds ▁to ▁accum ulate ▁in ▁high ▁quantities ▁that ▁will ▁last ▁for ▁dec ades . ▁This ▁has ▁led ▁to ▁a ▁co e volution ary ▁arms ▁race ▁between ▁the ▁cross b ill ▁and ▁l odge pole ▁p ine , ▁as ▁the ▁Cass ia ▁cross b ill ▁is ▁the ▁primary ▁select ive ▁agent . ▁In ▁result , ▁the ▁l odge pole ▁p ine ▁are ▁creating ▁con es ▁with ▁thick - scale d ▁con es , ▁whilst ▁the ▁cross b ills ▁have ▁evol ved ▁deeper ▁b ills ▁to ▁counter ▁this . ▁The ▁se eds ▁of ▁younger ▁ser ot in ous ▁con es ▁( 1 – 1 0 ▁years ) ▁are ▁harder ▁for ▁the ▁cross b ill ▁to ▁pr y ▁open ▁due ▁to ▁them ▁being ▁strongly ▁bond ed ▁together . ▁It ▁is ▁the ▁older ▁and ▁weather ed ▁con es ▁that ▁are ▁more ▁readily ▁accessible ▁as ▁the ▁scales ▁begin ▁to ▁separate . ▁The ▁Cass ia ▁cross b ill ▁will ▁mainly ▁eat ▁se eds ▁from ▁con es ▁on ▁the ▁p ine ▁tree ▁itself , ▁but