The population of emperor penguins in one part of Antarctica appears to be declining faster than previously thought, according to a new analysis of satellite imagery released on Tuesday.

About 44 per cent of migratory species worldwide are declining in population, the report found. More than a fifth of the nearly 1,200 species monitored by the UN are threatened with extinction.

Emperor penguins, considered “near threatened” with extinction, are the world’s largest penguins. They raise their chicks in Antarctic winter on patches of frozen sea ice. But if the ice breaks up before the chicks have fledged, most will die.

For the first time, United Nations members have agreed on a unified treaty to protect biodiversity in the high seas - representing a turning point for vast stretches of the planet where conservation has previously been hampered by a confusing patchwork of laws.

In a desperate effort to save a seabird species in Hawaii from rising ocean waters, scientists are moving chicks to a new island hundreds of miles away.

Dead and dying seabirds collected on the coasts of the northern Bering and southern Chukchi seas over the past six years reveal how the Arctic's fast-changing climate is threatening the ecosystems and people who live there, according to a report released Tuesday by U.S. scientists.

A bay-breasted warbler weighs about the same as four pennies, but twice a year makes an extraordinary journey. The tiny songbird flies nearly 4,000 miles (6,437 kilometers) between Canada's spruce forests and its wintering grounds in northern South America.

After a moment when hopes dimmed that the United States could become an international leader on climate change, legislation that Congress is poised to approve could rejuvenate the country’s reputation and bolster its efforts to push other nations to reduce greenhouse gas emissions more quickly.

Concealed behind trees near Lake Michigan, two scientists remotely manipulated a robotic owl on the forest floor. As the intruder flapped its wings and hooted, a merlin guarding its nest in a nearby pine darted overhead, sounding high−pitched, rapid−fire distress calls.

“It’s just a devastating decline,” said Stuart Pimm, an ecologist at Duke University who was not involved in the new listing. “This is one of the most recognizable butterflies in the world.”