Ruby-throated hummingbirds are lingering more often on the Carolinas coast in winter since the mid-1990s, says York County, S.C., naturalist Bill Hilton Jr., and increasing numbers are spending winters farther inland.There is a better reason for the hummingbirds to linger. It is the lack of food, not the cold which drives them south. Since more people are putting out hummingbird feeders, there is more of an incentive for the birds to stay.