Monarch Butterfly Biosphere Forest
CountryMexico
Area563 km2
TypeOyamel fir forest
Key SpeciesMonarch butterfly, oyamel fir, hummingbird
About Monarch Butterfly Biosphere Forest
High altitude fir forests northwest of Mexico City where millions of monarch butterflies gather each winter after flying up to 4,000 km from Canada and the USA. The butterflies cluster so densely on oyamel branches that boughs bend under their weight. The wintering sites were found by scientists only in 1975 after a decades long search. A UNESCO World Heritage Site, still threatened by illegal logging.