Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: > 300
Comments: This refers to global occurrences for the species as a whole and includes introduced populations in Hawaii, Australia etc., as well as central and South America. In these places and where non-migratory native populations occur, habitat may be more or less used all year. North American populations also have a lot of breeding habitat, most of it patchy and suboptimally managed for Monarch survival, but still producing millions of adults each summer. These face an annual bottleneck in terms of dependence on a few dozen overwintering areas. Western North American populations may also be under pressure from scarcity of good breeding sites, especially in dry years, and incompatible management.