Visiting each a dozen times during optimal conditions from May through October, searchers did both visual-encounter surveys (walking, turning over rocks and logs) and artificial coverboard surveys (for which they placed boards on the ground that snakes might hide under). Despite just three sightings, social media outreach they’d done to solicit public engagement yielded considerably better returns; after parsing information received via phone and email, they logged 20 reliable sightings from across the province.

These sightings will help refine Zahavich’s habitat model for choosing further monitoring sites. That’s because “critical habitat” for a species includes a variety of features required to meet an animal’s needs. The smooth greensnake is largely insectivorous, consuming spiders, crickets, caterpillars and the like, burrowing into soft substrates as well as climbing shrubs and tall grasses in search of food. But though such opportunity is mainly found in open habitats — moist meadows and fields, wetland edges, forest clearings, open woodlands — the species has needs beyond those of foraging. Hibernation, for instance, often communal, takes place in small mammal burrows, rock crevices and ant mounds that provide refuge below the frost line. Post-mating females lay an average of seven cylindrical eggs in late summer in rotting logs, stumps, vegetation or other warm environments. These hatch rapidly in one to three weeks; hatchlings, measuring nine to 16 centimetres, are highly vulnerable until they mature in about two years. Predators include birds, small mammals and other snakes.

Zahavich notes that data are lacking on all these life-history components in P.E.I. “We just have no baseline,” she says. “Now we’ve learned what works to establish monitoring sites and hope to gather data into the future that can show whether populations are increasing or decreasing over time.”

There are many questions yet to be answered. For instance, have agricultural chemicals limited insects that would sustain larger populations? In the scientific literature, smooth greensnake deaths and population declines have been linked to insecticides, herbicides and the compounding effects of habitat loss. Small size, limited reproductive output and high rates of juvenile mortality may also make the species sensitive to environmental changes such as prey reductions resulting from the drying of meadow habitat due to climate change or groundwater depletion.

“If conservation measures are needed,” says Zahavich, “and we know there are sites important to the species — like, say, hibernacula — we’d work with landowners on a spectrum of options.”

In the meantime, Islanders can help by keeping their eyes peeled and cameras ready for this delicate green phantom.

This story was created in partnership with Environment and Climate Change Canada.