Implementing radio telemetry to track monarch butterflies produces robust datasets to estimate monarch movement paths, habitat utilization, and perceptual range

Habitat loss in the summer breeding range contributes to the eastern monarch butterfly (Danaus plexippus) population decline. Habitat restoration efforts include increasing native prairie plants for adult forage and milkweed (Asclepias sp.) for oviposition and larval development. Monarch butterflies are highly mobile, and females are not milkweed patch residents. Improved understanding of how monarchs move through the landscape and utilize resources can support the development of biologically relevant habitat restoration plans.
Over five years, we studied non-migratory female monarch butterfly movement using radio telemetry. Radio tagged females were tracked in areas containing different configurations of adjoining habitat classes. Movements and behaviors of approximately 275 individuals were recorded and georeferenced for up to an hour each after release in prairies, crop fields, and grass-dominated cover. Assuming straight flight paths between locations, flight step lengths and turn angles were analyzed. Habitat utilization was analyzed by the amount of time monarchs spent in each habitat classification. Based on observations of direct flight steps into a prairie, we estimate that the functional perceptual range is at least 50m. These results help inform how different habitat distributions and spatial configurations can influence monarch productivity at the landscape-scale and further illustrate how understanding animal space use, resource selection, and movement patterns can support viable conservation plans.