The vast majority of owl species are forest dwellers. Few species live at high elevations or in very dry habitats. Most owls are sensitive to disturbance, but a few species adapt well to living among humans in suburban or urban areas. The eastern screech-owl is a good example. Members of the group called fishing owls are unusual for their habit of living near forest streams or in mangrove swamps and feeding mostly on fish. Only a few owl species undergo true migrations. Most species live in the same place year round. In winters when populations of small rodents such as lemmings or voles are low, northern owls may leave their usual home ranges and invade southern regions.