The are some fir tree forests in Mexico that are reputed to have butterfly populations so dense that their collective weight is sufficient to occasionally break off tree branches.
Monarchs living east of the Rocky Mountains in North America fly south each fall, gathering in central Mexico's Oyamel fir forest for the winter. Millions of Monarchs gather in the this forest area, covering the trees so densely that branches break from their weight. Scientists aren’t sure how the butterflies navigate to a place they have never been. No other population of Monarchs migrates this far.
Has this ever actually happened? If so, has it ever been photographed or captured on video?