A monarch butterfly in Mexico
Media playback is unsupported on your device

Drought reduces number of monarch butterflies migrating to Mexico

22 November 2011 Last updated at 16:51 GMT

Millions of monarch butterflies migrate from Canada and the US to Mexico every year.

But this year the sanctuary expects fewer winged visitors as the prolonged drought in the US and Mexico has affected their numbers.

Liliet Heredero reports.