In this month’s newsletter:
- learn about butterflies and caterpillars at the dunes in 2024, and
- find volunteer positions now listed on Volunteer Ottawa.
Butterflies at the Dunes in 2024
By Berit Erickson
All photos taken by Berit Erickson at the Pinhey Sand Dunes, unless otherwise stated.
In 2019, we began creating the Sanctuary for Butterflies and Pollinators at the Pinhey Sand Dunes, dune 2. We chose species suitable for this open, sandy landscape that create shelter for insects, and that provide food – flowers with nectar and pollen, and host plants for butterflies.
While adult butterflies drink nectar from flowers, their caterpillars eat leaves of their host plants. Different species of butterfly caterpillars eat different plants. As we add new species of host plants at the dunes, we can support more species of butterflies. As we create more and larger patches of host plants, we’re seeing more butterflies and caterpillars. In 2024, there was a dramatic increase in the number of caterpillars of several common butterfly species.
American Lady caterpillars
In June, we saw American Lady butterflies (Vanessa virginiensis) at the dunes drinking nectar from flowers, like Black-eyed Susans (Rudbeckia hirta), and warming up on the sand. They also laid eggs on one of their host plants, Pearly Everlasting (Anaphalis margaritacea). Later in June, we began seeing American Lady caterpillars on many of our Pearly Everlasting plants.
In 2023, volunteers counted only 6 American Lady caterpillars at the dunes. In 2024, there were approximately 400! What a success. Because birds were eating the caterpillars, we covered some Pearly Everlasting plants with mesh enclosures to protect them.
Giant Swallowtail caterpillars
In 2023, we began adding Hop Trees (Ptelea trifoliata), a host plant for the impressive Giant Swallowtail butterfly (Papilio cresphontes). Prickly Ash (Zanthoxylum americanum) is actually the local host plant for Giant Swallowtail butterflies, but it would spread too aggressively in the dune sand. Instead, we planted Hop Trees, even though they typically grow in South-western Ontario.
Two Giant Swallowtail caterpillars were found on our little Hop Tree saplings in 2023. In 2024, volunteers counted over 300! Again, we used mesh enclosures to protect the caterpillars from predators. In September and October, numerous Giant Swallowtail chrysalides were spotted attached to the inside of the enclosures.
Giant Swallowtail butterfly photo (left) taken in my residential garden.
Mid-summer Tiger Swallowtail
In July, we were also excited to see a newly identified butterfly species — the Mid-summer Tiger Swallowtail (Papilio canadensis x glaucous). For more information about the taxonomy of this species, see the Butterflies of Ontario’s Mid-summer Tiger Swallowtail page, and the Toronto Entomologists’ Association’s Tiger Swallowtails: Making Observations in 2020 page. We later found a Mid-summer Tiger Swallowtail caterpillar on one of our Hop Trees.
Other butterfly species
Every year, Monarch butterflies (Danaus plexippus) are common visitors to Dune 2 because of the large patches of Common Milkweed (Asclepias syriaca) that naturally occur here. Milkweed is the Monarchs’ host plant. We’ve also been adding Butterfly Milkweed (Asclepias tuberosa) in dry areas, Swamp Milkweed (Asclepias incarnata) to low-lying moist spots, and Whorled Milkweed (Asclepias incarnata) in a few different test locations. We hope to support more of these threatened butterflies as we grow more milkweed.
In moist areas, we’re also planting Golden Alexanders (Zizia aurea), the host plant for Black Swallowtails (Papilio polyxenes). Several species of sedges consistently attract skipper butterflies. As well, native trees growing in the surrounding forest are host plants for many other species of butterflies and moths that we see visiting dune flowers for nectar.
Throughout the spring and summer, visit or volunteer at the Pinhey Sand Dunes to see butterfly visitors and their offspring.
Friends of Pinhey Sand Dunes now on Volunteer Ottawa
By Berit Erickson
Friends of the Pinhey Sand Dunes is once again listing volunteer positions on the Volunteer Ottawa website. Since this is the central hub for volunteering in the city, we’re glad to be back. We hope to find more volunteers this year, allowing us to ‘clean’ more sand, add more native plants, and host more community education events. So far, the response has been enthusiastic.
Visit Volunteer Ottawa to read about the following positions:
- Weekly Dune 1 Maintenance
- General Dune Maintenance, Weekly or Casual
- Newsletter and Social Media Writer
- Photographer
- Butterfly Sanctuary Planting and Maintenance
To find our listings on the Volunteer Ottawa website:
- Click Volunteer on the menu bar.
- Then, click search for volunteer opportunities.
- Type Pinhey Sand Dunes in the Search box.
For more information, contact Berit Erickson, Chair of Friends of the Pinhey Sand Dunes.