Departure: Slow, Gradual, Uncertain

February 28, 2019 by Team Journey North

Gradual departure is underway from the sanctuaries along the California coast but what's happening in Mexico is uncertain. Why do monarchs migrate in the spring? Where do they go - and why?

“Activity levels continue to be really high and mating is happening meter after meter!” reported Estela Romero from El Rosario Sanctuary on Sunday, February 24, 2019.

Are They Really Leaving?

Monarchs are moving from the core sanctuary sites, reports Estela from Mexico, but it’s unclear where they’re going.  Have they moved elsewhere on the mountains, have they begun spring migration, or some of both?

“We continue to wonder if an early signal of departure is gradually happening, right under our noses. On Sunday afternoon around 5 pm many, many monarchs were overflying the downtown area as if gliding downhill from Sierra Chincua and El Rosario Sanctuaries.” More…

Also on Sunday, February 24th an observer witnessed a flight of northbound butterflies outside of the sanctuaries near the town of Zitacuaro:

“All butterflies were headed north and we definitely saw over 1000.”

So people are continuing to speculate: Are the butterflies abandoning the sanctuaries early this year and heading north? If they migrate early to the breeding grounds will milkweeds be ready?

Why Migrate North in the Spring?

A reader wrote to ask:

“Why do monarchs leave Mexico in the spring and migrate north? Is it because it gets too hot in Mexico during the summer? Does milkweed not grow in Mexico?” More…

Western Monarchs: Where will they go?

As Western monarchs slowly leave the safety of their groves along the California coast on their spring migration, where will they go? Knowing where they came from last fall may give us a clue.  Let’s look where monarchs tagged by citizen scientists in the West were spotted at the California overwintering sites. More…