Journey North - Monarch Butterfly and Milkweed observations by volunteer community scientists across Central and North America (1996-2020)

This data package contains monarch migration data (1996 - 2020) across North America collected by 42,518 community scientists for Journey North, a crowdsourced participatory science program of the University of Wisconsin-Madison Arboretum. The Journey North Monarch and Milkweed project is an ongoing study of monarch migration phenology conducted at broad spatial and temporal scales. Since 1996, community scientists have tracked first arrival dates and breeding and feeding behavior as well as the onset of fall migration, fall roosts, and peak migration events. Community scientists have also tracked the first emergence of milkweed in the spring and the presence of milkweed across the landscape during the summer, fall-winter months. The focal species is the Monarch Butterfly, Danaus plexippus. Community scientists indicate when known milkweed species in submitted comments.
Journey North data is observational and often opportunistic in nature. Observers do provide estimates of the number of adult monarch butterflies sighted during an observation. However, observers do not follow standardized methods for counting species observed. Observers do not observe at set times of the day; do not repeat observations regularly, and are not required to provide the length of time during which a specified number of species observed were counted. Therefore, it is recommended that this dataset be analyzed to indicate presence, not abundance. Additional contextual information is provided as text in the comments field of the dataset. The Journey North Monarch and Milkweed project dataset is hosted by the University of Wisconsin-Madison Shared Web Hosting Service.