Each fall, monarch butterflies embark on an incredible migration to their wintering grounds. West of the Rockies, the population heads to the Pacific coast, where they gather in scattered roosts in the trees in central and southern California. The eastern population, which makes up the bulk of the monarch population in North America, travels from as far north as southern Canada down to a specific area in the mountains of Mexico called the Monarch Biosphere Reserve northwest of Mexico City. There they all gather at just a handful of roost spots at high elevation to wait out the winter.
Both populations of monarchs are in real trouble, with numbers plummeting in the last few decades by as much as 90 percent for the eastern population and by over 99 percent for the western population.
Each of us can help turn the tide for these magnificent butterflies. Here are six ways to support fall-migrating monarchs:
Plant Fall Nectar Sources
Adult monarch butterflies feed on flower nectar. You can help monarchs refuel on their long migratory journey by planting native wildflowers that bloom in the late summer into the fall. Asters and goldenrods are great choices, and there are native species of each in almost all parts of the country. The bonus is that these wildflowers will provide beauty to your yard or gardens in addition to helping out the monarchs.
These regional guides to nectar plants for monarchs and other pollinators are a great place to start.
Don’t Spray Pesticides
Monarchs are insects, so it’s no surprise that insecticides will kill them. Avoid spraying any insecticides in your yard, but especially on fall-blooming plants that monarchs are likely to visit along their migration routes. Don’t fall for marketing claims of mosquito spray companies that say their sprays will kill mosquitoes but not beneficial pollinators such as monarchs. That’s simply not true. Instead, follow organic gardening techniques that don’t rely on pesticides and these natural ways to reduce mosquito bites that won’t harm monarchs.
Avoid Pre-Treated Plants
Not all pesticides are sprays. Neonicotinoids are a class of systemic insecticides which means that when treated, a plant absorbs the insecticide into all of its tissues–including the nectar–making it toxic to any insect that feeds on it. Research has shown that neonicotinoids can harm monarch butterflies. Before purchasing plants, ask at your local nursery or garden center if they’ve been treated with neonicotinoids. Many plant growers and garden centers now label plants that have been treated. If they can’t answer or if the plants are treated, use your power as a consumer and let them know that you will shop elsewhere.
Migrating monarchs often gather in trees at night or during periods of high winds and bad weather. Planting native trees in your yard and supporting community tree-planting efforts where you live can provide this important habitat for the butterflies. Lots of other wildlife will benefit from the habitat trees provide too.
Support Monarch-Friendly Agriculture
For the eastern monarch population in particular, which migrates along a central flyway from Minnesota down through Texas on their way to Mexico, agricultural practices can have a big negative impact. This route happens to follow along America’s “corn belt” where over 90 percent of the native grassland habitat that monarchs rely on during migration is gone, much of it converted into industrial farms that offer little or no habitat. Heavy reliance on herbicides such as glyphosate and insecticides such as neonicotinoids and dicamba, an agricultural pesticide that has been shown to drift into natural areas when used, takes a further toll.
Join the National Wildlife Federation to support our work to protect America’s grasslands and to promote wildlife-friendly agricultural practices.
Take the Mayors’ Monarch Pledge
Engage your community’s leadership on monarch conservation by promoting the Mayors’ Monarch Pledge. Mayors and other municipal leaders can spearhead local monarch conservation efforts by following the recommendations of the pledge, which requires leaders to commit to taking actions that will help monarchs. Actions range from changing weed ordinances so that they accommodate monarch-friendly plants to reduction or elimination of pesticides on city property to issuing an official monarch conservation proclamation and launching education campaigns on planting for monarchs in the community.