A migrating herd of wildebeest is seen in Masai Mara, Kenya. DEPMICRO/Newscom
A flock of Snow Geese are seen migrating at Bombay Hook National Wildlife Reserve in Delaware. PTS/Newscom/File
Migrating pelicans from the Gulf of Mexico swarm the pond at the Holiday Mobile Home Community off Horseshoe Lake Road in Pontoon Beach, Ill. in 2001. David Y. Lee/SHNS/Newscom/File
Each year, some 250 million monarch butterflies arrive to the luscious volcanic highlands of central Mexico, guided to the area by an inexplicable internal clock known scientifically as circadian. The monarch butterflies travel up to 3,000 miles to the state of Michoacan, which becomes the butterflies' winter getaway. Zuma/Newscom/File
Swans rest at the Yellow River wetland in Pinglu County of Yuncheng City, in northern China's Shanxi Province, on Jan. 16. Many swans migrate to the wetland in winter as the result of environmental and ecological protection efforts. PTS/Newscom
Every year, North Atlantic Humpback Whales migrate south to the Silver Banks, a small area 80 miles southeast of Grand Turk, to breed and give birth to their calves. January through March, the Warm tropical waters of the Banks come alive with constant displays of breaching, finning, lobtailing and spyhopping. DBC/Newscom/File
Black-headed gulls fly at the Dian Lake in Kunming, Yunnan province, China on Jan. 14, 2007. Lots of black-headed gulls migrated from Siberia to spend the winter at Dian Lake in Kunming. The Black-headed Gull is a small gull which breeds in much of Europe and Asia, and also in coastal eastern Canada. Most of the population is migratory, wintering further south. Leon Ma/ColorChinaPhot/Newscom/File
A flock of birds flies in the sunset. DEPP/Newscom/File
A herd of wildebeest is seen migrating across the African savannah. PTS/Newscom/File
Hundreds of migratory swallows take a rest on electrical wires in Shanghai, China. The birds are making the long journey East to seek warmer climates over the winter months. Phototex/WENN/Newscom/File
Sockeye Salmon leap upstream at Brooks Falls in Katmai National Park in Alaska. PTS/Newscom/File
A migrating herd of zebra crosses a river in Masai Mara, Kenya. DEP/Newscom
A large flock of starling birds fly over an Algiers park at sunset, seeking an area to land on the evening Feb. 15, 2006. Hundreds of millions of birds migrate in the spring from Africa to Europe. Fayez Nureldine/AFP/Getty Images/Newscom
A Robin, after gorging on berries from trees in a Clearwater, Fla. neighborhood, wades into a puddle to take a bath. Robins, which migrate south for the winter, have been moving through the area. Jim Damaske/Times/Zuma/Newscom
Iran and five world powers agreed last week to extend by four months a deadline for reaching a final deal aimed at preventing Iran from acquiring a nuclear bomb. But a yawning gulf still has to be bridged.
Though diplomats from Iran and six world powers are talking up the “substantial progress” that led to an extension of nuclear talks until November, crucial differences still threaten a final deal to ensure Iran can never produce a bomb.