The most important food resources for this species are the seeds (pine nuts) of various pines ("Pinus" sp.), principally the cold-climate (far northern and high altitude) species of white pine ("Pinus" subgenus "Strobus") with large seeds: "P. armandii", "P. bungeana", "P. cembra", "P. gerardiana", "P. koraiensis", "P. parviflora", "P. peuce", P. pumila", "P. sibirica" and "P. wallichiana". In some regions, where none of these pines occur, the seeds of spruce ("Picea" sp.) and hazel nuts ("Corylus" sp.) form an important part of the diet too. The forms that take hazel nuts have thicker bills for cracking their hard shells, with a special ridge on the inside of the bill edge near the base. If the shell is too hard, it holds the nut between its feet and hacks at it with its bill like a chisel.