Seen most often in North America, the beautiful winged insects have long fascinated scientists with their migratory abilities as they travel up to 3000 miles to Michoacán, Central Mexico for the winter and make a northward return journey in spring.

Neurobiologists at the University of Massachusetts Medical School in the USA have discovered that these amazing insects have inbuilt biological compasses, which are not only sensitive to light but can also sense the direction of the Earth's magnetic field.

Their most recent study Found that the Monarch butterflies seem to primarily use the sun to navigate, with the magnetic compass serving as a backup system on cloudy or overcast days.
Furthermore, their magnetic directional guides are activated by certain wavelengths of ultraviolet and blue light, which peak during summer and signal to the butterflies that it is time for southward bound flight.

What a remarkable and precise ability! Many thanks, University of Massachusetts scientists, for these fascinating insights.May the world of animal intelligence inspire us toward ever greater appreciation and respect for the wondrous butterflies and other myriad creations of Nature.

http://www.telegraph.co.uk/earth/wildlife/7855868/Monarch-butterflies-use-internal-compass-to-find-their-
way.html
http://scienceblogs.com/grrlscientist/2010/01/migratory_monarch_butterflies.php
http://www.sciencedaily.com/releases/2010/01/100125094645.htm