U.S.-Mexico border fence may harm animal migration A plan to fence off a third of the U.S. border to stop illegal immigration from Mexico may harm migration routes used by animals including rare birds and jaguars, environmentalists and U.S. authorities warn. The House of Representatives passed a bill this month authorizing the construction of about 700 miles (1,120km) of double fencing along the 2,000-mile (3,200-km) border, which was crossed by more than one million illegal immigrants last year. The proposal, which the Senate is expected to vote on in coming days, seeks to build continuous barriers separated by an access...