Millions of birds travel between their breeding and wintering grounds during spring and autumn migration, creating one of the greatest spectacles of the natural world. These journeys often span incredible distances. For example, the Blackpoll Warbler, which weighs less than half an ounce, may travel up to 1,500 miles between its nesting grounds in Canada and its wintering grounds in the Caribbean and South America.
Click here for original story, Cities can help migrating birds on their way by planting more trees and turning lights off at night
Source: Phys.org