Millions of black and orange wings will flutter across the U.S. this spring, as the monarch butterflies make their annual ...

The population wintering in central Mexico's forests occupied 4.42 acres, up from 2.22 acres during the previous winter.

US butterfly populations are declining because of insecticides, climate change and habitat loss, with the number of the ...

As summer comes to an end and temperatures start to drop, the butterfly migration season begins. The first few weeks of ...

A new study, involving researchers from the Institute of Science and Technology Austria (ISTA), suggests that the butterflies’ varying migration distances are influenced by environmental factors ...

Colony estimates at central Mexico overwintering sites indicate that monarch butterfly (Danaus plexippus) populations have declined over the past two decades. Among the leading causes of this ...

and is seen in species as varied as monarch butterflies, caribou, and baleen whales. The main source of energy used for migration is fat. Fat stores about 8–10 times more energy than the ...

The journey is the most evolutionarily advanced migration of any known butterfly, perhaps of any known insect. But climate change and habitat loss, both in the forest (photographed here in ...

The natural phenomenon of the iconic monarch butterflies migrating south for the winter is a fascinating one - and it's one ...

Monarch butterflies -- including western monarchs ... their chrysalises when conditions are no longer suitable for fall migration. Though the field survey showed that monarch arrival times ...

Monarch butterflies—including western monarchs ... their chrysalises when conditions are no longer suitable for fall migration. Though the field survey showed that monarch arrival times did ...