Monarch Migration

Farewell to the monarchs, beautiful kings and queens of the insect world.  

Monarch butterfly stocks up on nectar for the long flight south.

Monarch butterflies are fluttering and feeding all over eastern Long Island right now. They’re in the garden, by the roadside, and over the fields, preparing for fall migration to Mexico.

Monarch Watch, a website devoted to monarch conservation, estimates the peak days in “monarch abundance” to be September 8-20, so we’re right on schedule.

The monarch life cycle is extraordinary, as it takes several generations to complete a year’s cycle. Every fall, eastern monarchs migrate thousands of miles to spend the winter in Mexico’s Sierra Nevada. In March or April the butterflies return to the southern United States, seeking milkweed plants on which to lay their eggs.  The migrant generation will die before reaching the northern states.  Further colonization depends on the next generation.

After four days or so, the caterpillars hatch. They live on milkweed for about two weeks until fully grown.  Then they spin a chrysalis, inside which they metamorphose from caterpillar to butterfly. They emerge after about 10 days, and continue their parents’ journey north, laying eggs as they go.  The next generation of eggs will hatch in May and June, the third in July or August.  These butterflies will live just two to six weeks.

But the fourth generation of monarchs, emerging in late summer or early fall, will live as long as eight or nine months. These are the migrants that complete the cycle, flying south in early fall and returning in the spring.

They must survive wind, weather, and automobile windshields. Hungry birds are less of a threat since the caterpillar’s milkweed diet makes the monarchs poisonous to most birds or, at least, bad-tasting. The biggest threats to the monarch’s existence are climate change and illegal logging in Mexico, although recent reports from the World Wildlife Fund indicate that logging within the butterfly sanctuary has ceased.

To help scientists learn more about monarchs, you can participate in a citizen science project at Monarch Watch, tracking butterfly sightings and even tagging the insects with tiny tags.

Explore posts in the same categories: 2012, Fall, In the Country, insects, Seasons, Summer, Wildlife/Natural History

Tags: monarch butterflies, monarch butterflies Long Island, monarch butterfly climate change, monarch butterfly life cycle, monarch migration, threats to monarch butterfly

You can comment below, or link to this permanent URL from your own site.