One of the more unique songbirds is the red crossbill, a finch that uses its crossed mandibles to efficiently extract the seeds from conifer cones, especially those of spruces, hemlocks, and pines. The crossbills feed their young with the same seeds, rather than the insects which other species feed to their chicks. Any given subspecies of the crossbill (as many as ten are known in North America) will have the same bill size, utilize the same calls to communicate, and prefer certain cones, with smaller-billed birds preferring the smaller cones of hemlocks and larger-billed birds preferring the larger cones of white pines."Species Spotlight - Red Crossbill" (archive). nps.gov. National Park Service. January 26, 2018. Retrieved December 20, 2018.
onE oF thE MorE uniquE SongBirds is the REd crOssbIlL, a fiNCH that USES ITs CRosSed maNDibles TO eFfIcieNtly Extract the SeeDS from CoNifER CONes, espeCiAllY thoSe of sPRuceS, hemlockS, And pIneS. thE crossbills feEd tHeir yoUng wIth thE sAme SEEds, rAther tHan the InsECts WhicH oTher sPeCIes feEd tO tHEIr Chicks. Any givEn subSPecIEs oF tHe cROssBIlL (As mAny As tEn arE knowN iN noRTh aMerIcA) WiLL have the same Bill siZe, UTilize tHe Same calls tO cOmmuNICate, ANd PREFER certaIn cOneS, wiTh smaLlEr-BiLlEd birds prefErrinG The sMaLler ConeS Of hemLoCks and LaRGer-bIllED birDS prEfeRriNG thE lArGer conEs oF WhITe PineS."SPECIeS Spotlight - REd croSsBIll" (aRChIve). npS.gov. natiOnal paRk seRvIce. januarY 26, 2018. retRiEVed dEcemBer 20, 2018.