Scientists may soon be able to monitor whole ecosystems in real time.

"In 1804, a young naturalist named John James Audubon tied silver threads to the legs of the eastern phoebes, tiny white-and-brown songbirds, that lived in a nest near his home near Philadelphia. The birds soon flew away for the winter. The following spring, two returned with threads still attached. The experiment marked the first recorded use of bird banding in America, a technique for studying migration patterns.

More than two centuries later, technology, particularly the wonder of GPS, has turned silver threads into tags, sensors, and other devices capable of tracking all kinds of species around the world. Today, researchers get text-message alerts from collars worn by elephants in Kenya...

Scientists may soon be able to monitor whole ecosystems in real time.

"In 1804, a young naturalist named John James Audubon tied silver threads to the legs of the eastern phoebes, tiny white-and-brown songbirds, that lived in a nest near his home near Philadelphia. The birds soon flew away for the winter. The following spring, two returned with threads still attached. The experiment marked the first recorded use of bird banding in America, a technique for studying migration patterns.

More than two centuries later, technology, particularly the wonder of GPS, has turned silver threads into tags, sensors, and other devices capable of tracking all kinds of species around the world. Today, researchers get text-message alerts from collars worn by elephants in Kenya...