Thousands of beautiful orange-black and white monarch butterflies fly a huge distance every year to get from their breeding sites in the northern U.S. and Canada to their wintering locations in Mexico and California. Colorado, especially its eastern side, lies on monarch migration routes. Butterflies usually fly along the eastern side of the Rockies. Every fall, starting from September and ending in mid-October, it's possible to witness swarms of monarchs in the gardens, parks, and open fields. After cold weather ends, monarch butterflies fly back north to lay eggs. They can only do it on the leaves of milkweed. Their spring migration takes place between March and June. However, it's usually not as massive as autumn migration.
Butterflies are looking for a place to snack on nectar so wildflower fields and gardens are their primary targets. Large numbers of monarch butterflies are reported in John Martin Reservoir State Park in the southeastern part of the state. In the north, they are often spotted in the Gardens on Spring Creek in Fort Collins. as well as in parks around Denver and especially in the Denver Botanic Gardens. It's also a great idea to stop by the Butterfly Pavilion in Denver. Not only do they have a vast pollinator garden designed to attract butterflies, but the pavilion also runs Monarch Magic days from mid to late September. During these days you can learn a lot about monarchs and see more than 200 non-migrating butterflies in their tropical conservatory.
Practical info
When can one see the largest number of monarch butterflies in Colorado?
During the fall months, from September until mid-October, visitors to Colorado can witness vast numbers of monarch butterflies in gardens, parks, and open fields. The migration during this time can be quite spectacular, with thousands of butterflies on display. While migration also occurs during the spring, between March and June, it's generally less impressive. Show more
What are some specific locations within Colorado where one can spot the most monarch butterflies?
In the state of Colorado, two places known for expansive monarch butterfly sightings are John Martin Reservoir State Park to the southeast and the Gardens on Spring Creek in Fort Collins and park areas in and around Denver further to the north. Wildflower fields and gardens are the preferred locations for monarchs, where they can feast on nectar to give them energy during migration and breeding. Show more
What is the critical resource that monarch butterflies require during their migration through Colorado?
Monarch butterflies depend immensely on nectar during their migration through Colorado, which serves as the critical energy source to fuel their journey. Milkweed is the sole host plant for monarchs, and it's rare in Colorado, making nectar sources essential to their food supply. Nectar from wildflower fields and gardens acts as a survival resource for monarch butterflies and their offspring. Show more
When is the best time to visit Denver's Butterfly Pavilion for Monarch Magic days?
Visitors looking to participate in Monarch Magic days at the Denver Butterfly Pavilion should plan their visit between mid to late September when the event usually takes place. These days are perfect for those who wish to gain a more in-depth understanding of the monarch butterfly and get up close and personal with over 200 non-migrating butterflies held in their tropical conservatory. Show more
Are monarch butterflies attracted to specific host plants, or can they lay their eggs on any plant?
Monarch butterflies are highly selective in their choice of host plants, and milkweed is the only plant capable of sustaining monarch caterpillars. With the shortage of milkweed in Colorado, it's vital to provide milkweed plants to help the declining monarch population recover. During their migration, however, monarchs primarily feed on nectar, visiting wildflower fields and gardens to replenish their fuel supply. Planting milkweed in your garden is an excellent way to draw monarchs to your backyard. Show more
