It’s a dazzling display: every year, monarch butterflies swarm back to their over-winter grounds in Mexico in the millions. But like so many things, this may soon be a relic of the past.  Butterfly numbers are at an all time low and illegal logging in Mexico is the main culprit.

The World Wildlife Fund - Mexico conducted the supporting study that can be found in Spanish here.

The monarchs are so thick on the ground that it would be impossible to count them, so when the WWF conducts its annual census, they document the area of forest that is covered by the butterflies (as in the above video).  This year there were so few of them that the area hit an all-time low at 1.92 hectares (or 4.74 acres), not even a tenth of the all-time high of 21.0 hectares (52 acres).

According to butterfly-Conservation.org, illegal logging is the main reason for the downfall of the monarch:

Illegal logging

The likely reduced winter survival during December 2008 to March 2009 is almost certainly a consequence of illegal logging over the past decade that has either destroyed overwintering forests or degraded them so that they can no longer provide adequate protection for the butterflies.

Logging encroachments range from petty tree theft to the clear cutting of hundreds of hectares. Encroachments have occurred on and adjacent to the La Mesa, Chincua, Pelon, Rosario, Contepec and other overwintering areas.

Microclimate being destroyed

It is likely that the microclimate protection of all the colonies is becoming increasingly precarious. We can only hope that a storms in the US do not impact this year’s small colonies between now and the end of March. If they have another killer storm such as occurred in January 2002, it could degrade this migratory phenomenon to a possibly unrecoverable level.

American forests are also quickly disappearing which may have added to the distress of the monarch.  If you would like to do something about this problem then TAKE ACTION!