Spring Migration

There is nothing more exciting than finding a field full of native Milkweed plants. Even more exhilarating is when you discover Monarch butterfly eggs on the leaves of those plants!

Looking for Monarch butterfly eggs on young milkweed plants.

Monarchs are leaving a trail of eggs as they travel north. The first generation departing overwintering sites in central Mexico only migrates as far north as Texas and Oklahoma. The second, third, and fourth generations return to their northern breeding locations in the United States and Canada as spring progresses.

Female Monarchs find milkweed on their journey north through a combination of visual and chemical cues. When they land on a plant that might be Milkweed, they drum their forelegs on the surface to release chemicals. Then, sensors on their legs and antennae called chemoreceptors to identify if it’s Milkweed and the quality of the plant. They like placing their eggs on tender new leaves of the Milkweed plant, probably making it easier for the young larva to feed on.

Female Monarch depositing eggs on Tropical Milkweed (Asclepias curassavica). Purchase Tropical Milkweed seeds here: https://amzn.to/2xU5M1c

You can report your sightings at Journey North

Spring migratory routes are considerably more difficult to identify and study than fall routes because in the spring Monarchs are dispersed and consequently less noticeable than the fall migrants, which form roosts. Scientists are still learning about the Monarchs’ spring migration thanks to the help of citizen scientists from every US state and seven Canadian provinces. They report their first sightings of Monarch butterflies every spring. Through these reports, we can learn about when and where Monarchs travel as they migrate north in the spring.

Generation 1 monarchs are the offspring of the monarchs who overwintered in Mexico. Each successive generation travels farther north. It will take 3-4 generations to reach the northern United States and Canada.

High-quality habitat with abundant Milkweed is critical for Monarchs at this stage of their annual cycle. Explore Monarch Watch’s Milkweed Market and Monarch Joint Venture’s Milkweed & Wildflower Vendor Map. Plan and plant your pollinator garden today!

Young Common Milkweed (Asclepias syriaca). Purchase seeds here: https://amzn.to/3cK8ANe

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