July 29, 2022
One of the few plants in our pasture that our sheep won’t eat is milkweed. That’s very good news for the Monarch butterfly whose caterpillar is completely dependent on milkweed as a food source. Once the caterpillar morphs into a butterfly, it can feed on the nectar of many native plants. The caterpillar, though, is not so adaptable – it needs milkweed to survive.
In the fall, all the Monarchs (butterflies - not royals) living on the east coast migrate to Mexico and spend the winter there. It’s a 1,200-to-2,800-mile journey depending on their starting point in the fall. They spend the winter together congregating in one mountainous forest doing whatever it is butterflies do to pass the time.
In the spring they start their journey northward. They mate, lay eggs (on the milkweed plant) and die only a few hundred miles from their winter home. Their offspring make the next leg of the journey northward-and their offspring’s offspring make the next leg after that. The journey north to Canada takes 3-5 generations to complete, all hatched over the course of one summer.
The northbound butterfly’s life span is only about 5 weeks long- whereas the last hatch of the season, the southbound butterfly, lives 8 months. They in fact, make the 1,200-2,800 mile journey from Canada to Mexico themselves in one generation.
When our sheep pasture at Hill-Stead was neither grazed nor mowed it turned into brush and was well on its way back to woodland. Indeed, that is the natural progression of any field unless it is grazed, mowed, or burned. When it was subsequently mowed each year – nothing grew but grass, as most plants, including milkweed, don’t tolerate being mowed more than once or twice. With the reintroduction of grazing animals, however, milkweed in our pasture has begun to make a magnificent comeback. Our sheep won’t eat it, but they keep the brush down around it, allowing the milkweed to flourish. And where there is milkweed, there are Monarchs – at least for now.
Last week, the Monarch butterfly found its way onto the endangered species list. Maybe what we really need, to keep them from going extinct, is a corridor of small farms, up and down the east coast, with grass-fed pasture raised animals. If we graze it, they will come.