Monarch TrackerSightings & migration journal

Learn about monarchs

A short field primer to help you record what you see accurately and observe with care.

1.Egg
A single cream-coloured egg, about 1 mm tall, laid on the underside of a milkweed leaf. It hatches in roughly 3 to 5 days.
2.Caterpillar (larva)
Striped black, yellow and white, growing through five instars over about two weeks while eating milkweed almost constantly.
3.Chrysalis (pupa)
A jade-green case with gold flecks, hanging from a leaf, stem or ledge. Transformation takes roughly 8 to 14 days.
4.Adult butterfly
Orange wings with black veins and white-spotted borders. Summer adults live 2 to 6 weeks; the migratory generation lives many months.
The annual migration

Monarchs east of the Rocky Mountains spend the winter clustered in oyamel fir forests in central Mexico. In spring they move north, laying eggs on emerging milkweed; several short-lived generations continue the journey through the United States and into Canada.

The generation that emerges in late summer is different: it delays breeding, stores fat from nectar and travels south, sometimes thousands of kilometres, to the same wintering groves. Western monarchs follow a shorter route, overwintering along the California coast.

This is why the date of a sighting matters as much as the place. Records of first arrivals, larvae on milkweed and autumn roosts together sketch the shape of a season.

Observing responsibly