http://www.monarchnet.org/
"Monarch butterflies are one of the world's most famous insects, and in North America there are many citizen science programs where volunteers collect information on various aspects of its life.
The mission of monarchnet is to coordinate the integration of monitoring data from these programs and to make it available on this website, which serves as a resource for anyone who wants to know about monarch populations, i.e. government officials, researchers, members of the general public or NGOs. Since the partners represent the most important monitoring programs that collect data on monarchs, the collective data represent the most current and comprehensive information on the monarch biology.
We hope that by linking the data sets our efforts will foster collaboration between monitoring programs, promote the use of the data to answer scientific questions, increase participation by citizen-scientists in multiple programs and increase awareness of each monitoring program."
That map is of the flight path and not breeding locations.

