Guided by an internal compass, Monarch butterflies can determine the position of the sun and the time of day. With this data, the graceful beauties are guided in an annual migration unlike any other. The Monarch's migration sees some of them travel over 4,000 kilometers, from Southern parts of Canada to Mexico. Researchers have studied these insects for decades and have noted alarming changes in both the Eastern and Western populations, with an estimated 80% decline in just 20 years.

Offering some sign of hope - there are optimistic results from a recent butterfly migration count conducted by the Xerces Society, an international non-profit conservation group. The survey has revealed almost 250,000 Western Monarchs in California, compared to historic lows of just a few thousand in previous years. “It is great to see this rebound, it gives us a breath of time to do more planning and get more efforts on the ground, but we are not out of the woods yet,” says Professor Cheryl Schultz from the School of Biological Sciences, Washington State University.

Fly with us on this episode of The Big Blue Marble as we take to the skies to examine the threats impacting the two main migrating populations of Monarchs, why their protection is so important and how you may be able to help from your own home.