Fall Migration Starts this Month

By mid-month, the first members of the migratory generation will emerge in the north.

Monarch butterfly nectaring on swamp milkweed. Photo: Darlene in Leamington, ON

Here Comes the Migratory Generation

By mid-month, the first members of the migratory generation will emerge in the north. These butterflies are the great-great-grandchildren of the monarchs that left Mexico last spring. They have a long and challenging life ahead: they will migrate to Mexico this fall, survive the winter, and return in spring 2021 to begin the breeding season anew.

Monarch numbers reach their peak by fall migration. At no other time of year is the population larger. Monarchs produce four generations during the typical breeding season and the population grows with each new generation.

Report All Sightings

When you see a monarch, we want to know. Please report your sightings of monarch adults, eggs and larvae. Start now — and continue to report until you see your last monarchs of the season. Fall migration is about to begin!