The number of monarch butterflies spending the winter in the western United States dropped dramatically this year even as ...

The monarch butterfly population spending the winter in the western United States has declined to its second-lowest level in nearly three decades.

Overwintering populations of monarch butterflies in California have reached a near all-time low since records began, conservationists announced on Thursday. The ...

The number of monarch butterflies spending winter in the western U.S. dropped dramatically this year, despite moves to extend ...

We know small populations are especially vulnerable to environmental fluctuations, and we think that’s what happened this ...

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