The extinct Passenger Pigeon, once the most numerous bird species in the world, has had its closest living relatives identified by DNA extracted from museum specimens.The Passenger Pigeon was a forest nomad, breeding in vast colonies and following sporadic crops of acorns and chestnuts around the dense deciduous forests of the eastern and central United States. the forests were once so vast that they could support tens of millions of the birds, which were known to form flocks so huge that they darkened the sky when dispersing. This made them easy prey for hunters' guns, and the greed and over-exploitation...