Rare Butterflies of Salt Spring Island

Dun Skipper by Mike Yip

For more information contact : Salt Spring Island Conservancyinfo@saltspringconservancy.ca

250-538-0318265 Blackburn Road, SSI, BC, V8K 2B8

Mail to: PO Box 722 Ganges, SSI, BC V8K 2W3Text by J. Miskelly. All images © 2016

Dun Skipper by Mike Yip

Common Woodnymph by Mike Yip

Zerene Fritillary by Laura Matthias

What Can You Do?•learn about your local species and their habitat needs•support habitat protection and management for rare butterfly species•include native plants, especially host plants, around your home•leave some dead plant material around your yard or garden•leave an area of your yard wild and messy•participate in a Broom Bash or other invasive species control program and work to eliminate invasive species from your prop-erty.

Status and ThreatsSoutheastern Vancouver Island and the Gulf Islands have by far the highest butterfly diversity in coastal BC. Many species and varieties found in this area occur nowhere else in Canada, and several are endangered throughout their ranges. Unfortunately, local butterflies have declined greatly. The Victoria area has lost roughly twenty species, about half of its original number, since record keeping began in the late 1800’s. Most of this loss is due to historic conversion of native meadows and woodlands, first to farmland and then to residential and commercial uses. More subtle threats come from habitat change. There are several reasons for this. Many local meadows and woodlands were historically maintained by fire. In the absence of fire, these open ecosystems become closed forests and shrub thickets. Almost all of the butterflies that have disappeared from the region have herbaceous host plants, while most species whose larvae feed on shrubs and trees have persisted. Other threats include inva-sive plants like Scotch Broom, which trans-form mead-ows into shrublands; trampling, which can harm larvae or reduce host plant populations; and over-abundant deer, which can reduce host plant populations or ingest the larvae incidentally while eating leaves.

Biologists searching for rare butterfiles on Salt Spring Island, Photo by Laura Matthias.

What is SSIC Doing?Protecting habitat – we acquire conservation covenants and land acquisitions to protect ecologically significant habitat in perpetuity.Enhancing habitat – we restore habitat by planting native plants required by rare butterfly species, increase habitat for rare butterflies, maintain key habitat features in our nature reserves for butterflies.Surveying –we work with experts to increase our understand-ing of the status and distribution of butterflies on Salt Spring Island Outreach – we work to build knowledge of local butterflies and their habitat needs in the community to encourage other land-owners to enhance habitat on their own properties.Mitigate Threats – we work with partners and user groups to restrict habitat damage in sensitive areas.

Rare Butterfly Species on Salt Spring Island

Moss’ Elfin (Callophrys mossii mossii) Blue listRange: Moss’ Elfin ranges from southern BC to southern Califor-nia, east to the Rocky Mountains. The local subspecies (subspe-cies mossii) is found only in the region from southwestern BC to Oregon. Wingspan: 2.5 cm, Habitat: Rocky outcrops, cliffs, and hilltops, Host plant: Broad-leaved StonecropLifecycle: Adults are on the wing from mid-March to early May . They nectar from a variety of spring flowers, such as Spring Gold and lay eggs on stonecrop. Eggs hatch soon after laying and larvae feed on stonecrop buds, flowers, and leaves. Larvae pupate by late spring and the pupae remain dormant until the following spring. Threats: residential/commercial development; trampling on rocky hilltops; excessive deer grazing on stonecrop.

Common Woodnymph (Cercyonis pegala incana) Red listRange: Across southern Canada from Pacific to Atlantic, south to the southern United States. The local subspecies (incana) is restricted to south-western BC, western Washington, and north-western Oregon. Wingspan: 5 cm, Habitat: open woodlands, meadows, forest edges, Host plant: unknown grasses. Lifecycle: Adults have been recorded from late June to mid-September, but most are seen in July and August. Eggs are laid in grassy areas, mostly late in the flight season. As soon as the eggs hatch, the larvae become dormant without feeding until spring. They feed mostly at night, and spend the day hiding on the ground. Pupa-tion occurs by early summer and adults emerge after approx. one month. Threats: habitat loss

Propertius Duskywing by Laura Matthias

Moss’s Elfin by James Miskelly Common Woodnymph by James Miskelly

General InformationAll butterflies have a four-part life cycle, which includes egg, larva (or caterpillar), pupa (or chrysalis) and adult. In most local species the egg hatches one to two weeks after being laid. Only a few local species overwinter in the egg stage. All local butterfly larvae feed heavily on plant parts. Most species are quite host specific, and will feed only on a small selection of related plants, sometimes just a single species. When a larva has completed its task of feeding and growing, it often wanders a short distance and finds a hiding place before becoming a pupa. Pupae are unable to move around and are usually attached to a substrate. The adult butterflies emerge from the pupae and must stretch and dry their wings before they can fly. Males usually emerge first, and spend their time searching for females. Females are less active than males and spend their time looking for suitable egg-laying sites. Most butterfly species feed on nectar from flowers. Some species may prefer other sources of nutrients and energy, including tree sap, rotten fruit, animal droppings, or carrion. Depending on the species, the lifespan of the adult butterflies may range from only a week to several months. A few local species pass the winter hibernating as adults.

Butterflies of Salt Spring IslandIn the early 1900’s, several prominent butterfly researchers doc-umented the butterflies of the Victoria area and Cowichan Valley, but historic information on the butterflies of Salt Spring Island is almost non-existent. Visiting an area at different times of year and over a multi-year period is the best way to see all the butterflies that may occur there. To date, thirty species have been recorded from Salt Spring Island, including a few that haven’t been seen in decades.

Propertius Duskywing (Erynnis propertius) Red ListRange: The Propertius Duskywing is found from south-western BC to Baja California. Wingspan: 3.5 – 4 cm, Habitat: open areas with oak, Hostplant: Garry Oak, Adults are seen mainly April and May, but sometimes as late as July. They nectar on a variety of spring flowers. Eggs are laid on the leaves of Garry Oak and hatch after one week. Larvae construct shelters out of silk, sometimes folding leaves over the shelter, feeding on oak leaves mainly at night. In summer, the fully-grown larvae become dormant inside their silk shelters. The leaves fall in autumn with shelters and larvae still attached. In early spring, larvae ‘wake up’ in the leaf litter and pupate, with adults emerging a few weeks later. Threats: residen-tial/commercial development; succession of open woodlands to closed forest or shrub thickets; removal of oak litter.

Dun Skipper (Euphyes vestris) Red List; ThreatenedRange: The local population occurs from southwestern BC to California. Wingspan: 2.5 – 3 cm, Habitat: wetlands, ditches, disturbed areas, Lifecycle: Adults are on the wing from late May to early August, with most observations coming from June and July. They nectar on a variety of flowers. The larval hostplants are believed to be sedges. Eggs hatch soon after laying, and larvae construct shelters by tying sedge blades together with silk. After a period of feeding and growing, they become dormant inside silk chambers lined with wax. These are thought to protect the larvae from winter flooding. Larvae resume feeding in spring, pupate in late spring or early summer, and emerge as adults a few weeks later. Threats: draining and filling of wetlands; culverting of streams and

ditches. Zerene Fritillary (Speyeria zerene bremneri) Red ListRange: The Zerene Fritillary is highly variable species with many varieties. The species as a whole is found from southern BC and Alberta south to California and New Mexico. The local subspe-cies (subspecies bremneri) is found only in south-western BC and western Washington, having been extirpated from western Oregon. The current range in BC is unclear. Some experts believe it is confined to southern Salt Spring Island. Others believe that unusual fritillaries found on northern Vancouver Island may also be subspecies bremneri. Either way, it has disappeared from all of southern Vancouver Island. Wingspan: 5.5 – 6 cm Habitat: meadows, Hostplant: violets, Lifecycle: Adults fly from late June to early September. They nectar on whatever flowers are available in their dry habitats, including Bull and Canada Thistle, Yarrow, and Yampah. Eggs are scattered in dry vegetation, wherever the females can detect the scent of violet leaves. Upon hatching, the larvae become dormant without feeding. In spring, larvae locate violet plants. They feed on violet leaves during the night and hide on the ground during the day. They pupate in early summer and emerge as adults a few weeks later. Threats: Succes-sion of native meadows and open woodlands to Douglas-fir forest.

Dun Skipper by James Miskelly

Zerene Fritillary by James Miskelly

Zerene Fritillary by Laura Matthias

Common Woodnymph by Laura Matthias