Bald eagles are in the midst of record population growth in northern New England, where America’s national bird could soon find itself removed from all state endangered lists. The eagle was once completely gone from Vermont and New Hampshire and down to just 21 pairs in Maine. But wildlife officials and conservationists in the three states said the bird is repopulating fast, to the point where it has become a threat to rarer species in some areas. Wildlife officials attributed the bird’s comeback to habitat and environmental protection measures, such as the ban on the pesticide DDT, a change that made it easier for birds of prey like eagles to reproduce successfully. The bald eagles’ comeback in northern New England tracks in line with their population growth elsewhere in North America.