monarch-esa-petition-final_61585

Figure 8. Western monarch collection records across the calendar year. Dots represent monarch
specimens. Shaded regions are areas of high elevation (>2000 m). Figure 1 from Dingle et al.
2005, original caption omitted.
HABITAT
In general, butterfly habitat requirements include host plants for larvae, adult nectar sources, and
sites for roosting, thermoregulation, mating, hibernation, and predator escape (Zalucki and
Lammers 2010). In addition to these, the monarch butterfly requires conditions and resources for
initiating and completing migration both to and from winter roosting areas, making them
vulnerable to habitat degradation across wide areas. Because monarchs are host-plant specific,
they are entirely dependent on the abundance of milkweeds, and threats to milkweed thus
threaten their survival, as do threats to the specific forested areas that provide the microclimatic
conditions they need to survive the winter. Monarchs and their habitat are also highly vulnerable
Monarch ESA Petition 27