 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.In 1991, peregrine falcons had a successful nesting in Acadia for the first time since 1956.At least one pair and as many as four pairs have produced offspring over the years since 1991, totaling more than 160 chicks.