References
University of Minnesota (2018) University of Minnesota [Online]. Available at https://monarchlab.org/ ?/ biology-and-research/ biology-and-natural-history/ migration [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)] (Accessed 15 August 2019).
Arboretum University (1997) JourneyNorth [Online]. Available at https://journeynorth.org/ sightings/ (Accessed 15 August 2019).
Monarch Watch (2019) MonarchWatch.org [Online]. Available at https://monarchwatch.org/ tagging/ (Accessed 15 August 2019).
USGS (2012) Citizen Science Light Trapping in Grand Canyon [Online]. Available at www.usgs.gov/ centers/ sbsc/ science/ citizen-science-light-trapping-grand-canyon?qt-science_center_objects=0#qt-science_center_objects (Accessed 15 August 2019)