One way trip to Mexico for monarchs as cooler months approach Canada and the United States.

SIERRA CHINCUA, Mexico (Reuters) - From a distance, they appear like autumn foliage: millions of endangered monarch butterflies blanketing trees in a kaleidoscope of brown, orange and black. As the ...

The number of monarch butterflies wintering in the mountains of central Mexico dropped 22% from the previous year, and the number of trees lost from their favored wintering grounds tripled. Frost and ...

MEXICO CITYMEXICO CITY — The number of monarch butterflies at their wintering areas in Mexico dropped by 59% this year to the second lowest level since record keeping began, experts said Wednesday, ...

After flying some 3,000 miles from the northern U.S. and Canada to a remote forest in Central Mexico for the winter, tens of millions of monarch butterflies are making their way back north. These are ...

The first monarch butterflies have appeared in the mountaintop forests of central Mexico where they spend the winter, Mexico's Environment Department said Saturday. The first butterflies have been ...

A key monarch butterfly population is showing signs of improvement this year, but scientists warn the species remains in long-term decline-especially in the western United States. New data released by ...

Every autumn, millions of eastern North American monarch butterflies embark on a journey to their overwintering grounds in ...

The number of monarch butterflies at their wintering areas in Mexico dropped by 59% this year to the second lowest level since record keeping began, experts said Wednesday, blaming heat, drought and ...

correctionA previous version of this article misstated the nature of the eastern monarch butterfly's population decline in the past 25 years. The population declined but did not do so steadily. The ...