Monday, October 13, 2008

“Rare Creatures of Metchosin and Their Preservation.”

The Community House was packed with Metchosinites on Wed Jan. 26, when the APRM sponsored presentations on “Rare Creatures of Metchosin and Their Preservation.”

Metchosin resident Dave Nagorsen, former Curator of Small Mammals at Royal BC Museum started the evening with a talk on bats and small mammals. There are 30 mammals indigenous to Vancouver Island, of which 6 are at risk and 4 are (probably) found in Metchosin.
The provincially red-listed (our most serious category) American water shrew enjoys aquatic areas with lots of cover in the form of woody debris. It has not been found in Metchosin, but given its small size, its nocturnal behaviour, its preference for remaining under cover of woody debris on the margins of streams, it probably does inhabit relatively undisturbed parts of the Bilston system. It feeds on aquatic invertebrates and small fish.
The ermine, or short-tailed weasel is on our provincial blue-list (considered vulnerable). It is our smallest carnivore on Vancouver Island at 25-30 cm and weighs under 100 grams. It dines on small birds (including chickens), mice, and amphibians. It requires riparian habitat, rotting logs and a thick understory It has not been reported in Metchosin, but one was found dead near Sooke Road and had probably been killed by a cat.
Bats are the only mammals capable of flight. In summer, the females of most species congregate in maternity colonies while the males remain solitary. The life cycle of most of our bats during the winter season is a bit of a mystery; some hibernate in the area, while others probably migrate south. Bats need “bat” trees for roosting. These are dead, larger trees, often cedars, that are moderately decayed but with bark remaining. Woodpecker cavities also provide cover.
Townsend’s big-eared bats are blue-listed by the province. They are especially sensitive to disturbance, especially during their winter hibernation, and roost in caves or buildings. In Metchosin both summer colonies of females and hibernating winter colonies have been found at Mary Hill.
Keen’s long-eared bats have made the provincial red-list. They are sometimes found in high elevation caves. There is no record of these bats in Metchosin but someone’s cat on Tideview Rd. in East Sooke killed one, so they are likely in the vicinity.
Our native red squirrels have locally disappeared over the past 20 years and it is not clear if the culprit is the introduced gray squirrel, since the red eats conifer cones while the grays eat Garry oak acorns.
To help preserve these rare and threatened mammals we should: maintain wildlife trees, especially cedars; learn to identify species, remove bats from your home by exclusion, NOT extermination; maintain riparian habitats; “control cats” (who are devastating hunters of small mammals) and report suspected rare species to the Conservation Data Centre, Ministry of Water, Land and Air Protection.
Christian Englestoft of Alula Biological Consulting is involved in research of the red-listed sharp-tailed snake. This is a very small snake with juveniles only 10 cm in length, and adults under 35 cm; one half the size of normal garter snakes. Besides its small size, its easiest distinguishing feature is its tail. Although called sharp-tailed, the name is a bit misleading. In appearance the tail appears blunt, rather than pointed, but the tip has a sharp “hook”. They lay eggs rather than bearing live young, another point which sets them apart from garter snakes. Only 2 nests have ever been found.
These endangered snakes have been found in Metchosin, beside the Galloping Goose-near Pearson College, on Mary Hill. Besides the sharp-tailed snake, we have three species of garter snakes in Metchosin, none of which are dangerous.
Habitat that seems to appeal to sharp-tailed snakes includes south facing slopes, heat traps (gullies, forest openings) and lots of cover objects (debris, rotting logs, boulders).
Diet consists mostly slugs although they have been found eating salamanders.
These are very elusive, secretive creatures and it is easy to overlook them in the rush to develop a site. Care must be taken to ascertain if they are present and to maintain their habitat. It is crucial to leave rocks and logs and to minimize disturbance. Contact Christian Englestoft at if you think you have sighted this snake.
James Miskelly, MSc, spoke eloquently on rare and threatened butterflies of Metchosin. Southern Vancouver Island used to be world-renowned for its abundance of butterflies. In 1884 , George Taylor reported an “ extreme abundance of butterflies as one of the most noticeable features of the landscape”, of which there were over 40 species and from 1903 there was a quote about butterflies carpeting the sea and beaches.
Most butterfly species, in their caterpillar form, prefer specific types of plants to feed upon. With the conversion of the natural environment to an urban landscape, to agriculture and through forestry practices, all these food preferences have become increasingly scarce. Certain types of butterflies need woodland edges and trails, some need rocky bluffs or Garry oak woodlands and others have flourished in disturbed areas. The more varied the landscape, the more types of butterflies are likely to inhabit an area. Metchosin is special in the region because it retains a variety of natural habitats: relatively wild road-sides, some disused fields, forests, meadows, rocky knolls, wetlands, etc.
The propertius duskywing (a blue-listed species) will lay their eggs only on Garry oaks and after the caterpillars have pupated they remain in the leaf litter throughout the winter. They can only successfully survive if the leaf litter remains (hence, they are rare in Oak Bay where Garry oaks remain only in “neat” leaf litter free gardens).
Two other rare species that are found in Metchosin are the common branded skipper and Moss’ elfin. The Moss’ elfin caterpillars feed on stonecrop, which is suffering from predation by those ever hungry deer and from development of rocky bluffs. Common branded skipper caterpillars feed on native grasses, which have suffered a severe decline, especially from competition with introduced grass species.
BTK spraying for gypsy moth or in common garden practice, has been absolutely fatal where it occurred, wiping out populations of butterflies that take years to recover, if ever.
We are so fortunate to live in Metchosin, a community rich in natural landscapes, that can still provide habitat to our rarest creatures. Consider what you can do to increase the likelihood of survival for these living beings.

Host Plants or Food for Caterpillars

We cannot have butterflies without first having caterpillars. Perhaps even more important than the nectar flowers for the adults are the food plants for their young. Like some of our children, caterpillars are very picky eaters and each species will only eat from a very limited menu. Of course, when you are choosy about your foods and your food source disappears for whatever reason, you are apt to struggle for survival. A few species have learned to appreciate introduced plants but most are committed to their native flora. Planting some of these host plants today will help ensure there are butterflies for tomorrow.

Host Plants
Stinging Nettles for Milbert’s Tortoiseshell, Satyr Anglewing and West Coast Lady
Grasses and Sedges for Woodland Skipper, Arctic Skipper, *Common Branded Skipper, *Wood Nymph
Oceanspray and Hardhack for Western Spring Azure
Oceanspray, Saskatoon, Bitter Cherry for Pale Swallowtail
Saskatoon, Cottonwood and Bitter Cherry for Lorquin’s Admiral
Alder, Willows and Bitter Cherry for Western Tiger Swallowtail
Wild Strawberry and Potentilla for *Two-Banded Checkered Skipper
Stonecrop for *Moss’ Elfin
Carrot Family: Cous, Dill, Fennel for Anise Swallowtail
Native Violets for Hydapse Fritillary
American Winter Cress and Rockcress for Sara’s Orangetip
Western Bleeding Heart for Clodius Parnassian
*uncommon butterfly

Butterfly Nectar Plants

Generally speaking, the best butterfly nectar plants are those that are sunloving, purple, pink, yellow or white in color, and single-flowered rather than double flowered.
There are four basic guiding principles in arranging your chosen plants: (1) place shorter plants in the front (or outside edges) and taller plants in the back (or center); (2) place larval food plants in hidden and less obvious areas; (3) plant in large groups of one color rather than single plants of different colors; and (4) plan for a continuous bloom through the entire growing season with spring, summer, and fall blooming plants.

Spring: flowering currant, violets, cherry, crabapple, hawthorn, lilac, nodding onion, sweet William, heliotrope, camas
Spring-Summer: bleeding heart, columbine, lupine, coreopsis, phlox, dogwood, wooly sunflower
Summer: native roses, potentilla, sedum, fireweed, lavender, bee balm, butterfly weed, cow parsnip, coneflower, dogbane, marigold, zinnia, salvia
Summer-Fall: asters, pearly everlasting, yarrow, goldenrod, sunflower, fleabane, cosmos

No comments: