They’re not here yet, but in a scant few weeks Monarch butterflies will make it to our area as they reach the northern part of their migration pattern. We all know that they head to Mexico for the Winter, but their migration is more complicated than most folks realize. Let’s take a look at what really happens and learn a bit more about these fascinating butterflies.

The primary food source of Monarch butterflies (and the only food for their caterpillars) is milkweed. There are five types of milkweed in our area. The most common is called Common milkweed (hey, even botanists can have a sense of humor). The other four are Butterfly milkweed, Purple milkweed, Swamp milkweed and Whorled milkweed. The stuff we see around the edges of our dairy farm fields is Common milkweed.

The Monarch butterflies that we see in the middle of May are called Third Generation Monarchs. The females lay eggs on the underside of milkweed leaves. When the eggs hatch, the caterpillars eat the milkweed which contains toxins called cardenolides. Another example of Nature’s amazing adaptations, being able to eat these toxins has two benefits for the Monarchs. First, there are very few competitors for this food source. Second, the Monarchs and their caterpillars retain some of the toxins, causing predators to avoid eating them.

This Third Generation of monarchs only lives for a few weeks. The Fourth Generation grows up here in the North during the Summer. Once they become butterflies, the adults will fatten up on heavy nectar from certain plants other than milkweed. This last of the four generations lives the longest and makes the amazing journey down south to Mexico.

The Monarchs go all the way to the Oyamel fir forests in the high elevations of central Mexico. Oyamel (a.k.a., Sacred) fir trees grow in the mountains between 8,000 and 13,500 feet above sea level and provide the perfect conditions for Monarchs to spend the Winter until March.

The migration cycle starts with the First Generation of Monarchs that are born in Mexico. Those Monarchs start the return trip to the United States and Canada, arriving in the South in late March or early April. This generation is also fairly short lived, only lasting 2-6 weeks but give birth to the Second Generation.

The Second Generation is also short lived and migrate further north up to the middle of the Atlantic Coast. They give birth to the Third Generation which returns to the North. And then the whole cycle repeats.

It’s kind of amazing that none of the generations ever know anything about what the others do. Yet the whole thing works. And yes, those tiny little butterflies of the Fourth Generation really do fly 2500 miles to central Mexico!

Monarch butterflies are considered rare in New York and are listed as endangered in many other states. Their population has seen a tremendous decline during my lifetime. What can we do to help? Plant some milkweed. Don’t cut down milkweed that is already growing wild on your property. Use less weed killers.

There is milkweed growing alongside the southern side of my house, and a small patch in the backyard that my father and sister planted decades ago, specifically for the Monarch butterflies. I’m glad it’s there. I enjoy watching the butterflies on it and watching their striped caterpillars eating it.

I’ve just scratched the surface. Read more about it and get involved. Together, we can save the Monarchs.

Let’s all enjoy the outdoors!

John S. Van Etten is the current president of the Federation of Sportsmen’s Clubs of Sullivan County, Inc.