(AP) -- Experts are reporting a partial recovery in the annual winter migration of Monarch butterflies to Mexico following a devastating 75 percent drop last year.
The conservation group World Wildlife Federation Mexico says the orange-and-black butterflies from the U.S. and Canada are covering an area of forests that is more than double that of last year, when their numbers dropped to historic lows.
But WWF Mexico director Omar Vidal said Monday the numbers are still well below average.
The butterflies have occupied 9.9 acres (4 hectares) of colonies thus far in the 2010-2011 winter season - more than double the 4.7 acres (1.9 hectares) they covered last year.
They covered almost 20 acres (8 hectares) in the 2008-2009 season.
Explore further: Monarchs fly south for the winter