Monday, May 16, 2011

Winged Wonders of Metchosin - Butterflies of Metchosin

Two-banded Checkered Skipper

Flamboyantly garbed or mutely camoflauged, butterflies evoke a sense of delight…..Butterflies have become an pleasurable interest of mine over the past few years, although learning their identification has been a challenge. Understanding their complex life cycles, their needs and preferences, has broadened my understanding of the interrelationships between plants and animals and our place in their ability to survive.
James Miskelly, biologist and entomologist (bug guy), was the guest speaker at the April Talk and Walk, presenting beautiful photographs of our local Lepidoptera (butterflies and moths), while informing us of their multiple stages of life and the difficulties they must overcome in order to successfully produce succeeding generations of these lovely creatures..
There are sixty-eight species of butterflies on Vancouver Island, fifty-five of which are resident, three non-native and seven migratory. Thirty species have been recorded at my home on Camas Hill, although I have only seen twenty-six myself. Three other species are termed accidental, meaning they have arrived here by accident and soon left. Monarchs are one of these, they don’t naturally occur here, as their host plants, members of the milkweed family, are absent from Vancouver Island. Monarchs do occasionally show up, the result of a faulty guidance system, a severe storm or perhaps just an individual butterfly with a sense of adventure….
In 1884, George W. Taylor remarked on the extreme abundance of butterflies in the Victoria area, writing that “nearly forty species may be recorded as abundant”. Dr. James Fletcher noted in 1901 “the dead butterflies may be seen in vast numbers, floating on the sea around Vancouver Island (probably Pine Whites) or thrown up along the beach in windrows sometimes an inch or two deep”.
What has changed to bring us to the severely reduced numbers and species we have today? One of the reasons is likely the change in the landscape, the conversion of  grasslands and forests to urban, industrial and agricultural uses and the loss of micro and macro habitats; climate change might be having an impact as well.
Most adult butterflies have short lives. Once they emerge from their cocoons they generally have only a week or two to find a partner and reproduce. The temperature at which they can fly must be at least 10-12ºc and they don’t do rain-they are fair weather fliers. The female has to find just the right host plant on which to deposit her eggs. Host plants are the (often very specific) plant on which the young caterpillars feed and there must be enough of these plants, growing in the right conditions, in the sun, to ensure sufficient food for the caterpillars, until they are ready to pupate. Often with a late spring or early heat wave, the host plants are not in sync with the butterflies’ needs., they emerge late, dry up early, have poor bloom or sparse numbers. Nectar plants, the ones the adult butterflies use as a food source face the same requirements, they must be available at the right season with enough nectar to supply a butterfly’s nutritional needs. It’s a wonder any butterflies make it at all.. Rare butterflies, already struggling with low population numbers, can succumb to extinction rather quickly if there are a few bad years in succession. On top of all these factors, many, many other species think butterflies are a lovely meal. Birds eat them as both caterpillars and as adults; many butterflies have bits of their wings missing, showing near misses with a hungry bird. There are wasps who lay their eggs on living caterpillars, who will serve as meals to new generations of wasps. It’s a tough world out there for these gossamer winged beauties.
If you’re thinking that our cold, wet, grey springs lately might be hard on the early butterflies, you would be correct.
Moss' Elfin

One of our earliest flying butterflies is the Moss’ Elfin. With a wingspan of only 2 cm and cryptic brown colouration, it can be easy to miss. I have recorded them as early as late February, though more often in mid-March through to early May. This year they appeared in mid-April. This elfin is considered one of our less common species. It lays its eggs on the developing flower bud of our native broad-leaved stonecrop. The caterpillar must emerge, feed and pupate before the flowers are finished. In a year like this, when the elfins have been hiding under leaves, under rocks and in cracks in trees, waiting for weather in which they can fly, there is little time to complete their lifecycle. Stonecrop itself has been impacted by development, it grows on rocky outcrops and on cliff faces, areas which have seen a good deal of development in the last few decades. Deer, too, appreciate a tasty stonecrop morsel and the increase in deer and shortages in their food sources has put more pressure on stonecrop patches. When elfin populations have been decimated and their numbers are not abundant, there is a real possibility that these charming little butterflies might disappear forever.
Propertius Duskeywing
Propertius Duskeywing is another cryptically hued brown and grey butterfly that is in flight in April and May. It is a Garry oak obligate, meaning that is the only food source for its caterpillars. These butterflies are considered threatened, with rapidly declining populations. As you look around the Victoria area you might wonder why as there are still many oak trees in yards and parks. Unfortunately for the little Propertius Duskeywing, its caterpillars like to attach their cocoons to a leaf and overwinter in the leaf fall at the base of the trees. With our propensity for tidy lawns and yards, the caterpillars are raked into piles and sent to the compost or burn pile. The adult butterflies that have been fortunate enough to survive in a natural area, untouched by rake and lawnmower, don’t realize the danger of leaving the parks and venture out to any likely Garry oak, most of which suffer the indignities of our too tidy complex. If you are so fortunate to share your home with Garry oaks, please resist the urge to rake and burn….it’s easier on you and better for the butterflies. Go read a book instead.
Anise Swallowtail
One of the more common species in Metchosin are the swallowtails. Large and strikingly coloured, they are sometimes misidentified as Monarchs, although the species are much different. We have three species of swallowtails in Metchosin and the Anise can be distinguished from the others by the wide, dark band of scales across their upper wings. Flying in early April, it can be found in open, rocky areas, searching for springold, Indian consumption plants and cow parsnip, three native members of the carrot family. The Anise can have another generation during the summer, and as the rocky outcrops dry and the plants wither, they will seek out fennel and a variety of cultivated carrot family species on which to lay their eggs. Most gardeners remove them as pests, not realizing the beautiful Anise butterfly waits inside it’s less lovely young. 
2nd Instar Anise Swallowtail
The very juvenile, small caterpillars look like bird droppings, as they mature, they exhibit yellow spots, in their final stage they are a large green caterpillar with black bands in which there are yellow markings. Perhaps you can find it in your heart to reserve some of your carrots or fennel for these stunning butterflies (they only eat the leaves–not the roots).
Western Tiger Swallowtail
Pale Swallowtail
The large (7.6 cm) Western Tiger Swallowtails and their very similar Pale Swallowtail (9 cm) cousins can be seen in relative abundance from May through the summer and Westerns can be seen as late as September. The Tigers use native willows, bitter cherry and poplar while the Pales lay their eggs on red alders, Saskatoon, oceanspray and bitter cherry and both species use cultivated apple trees.
Spring Azure
Spring Azures are a small (2 cm), gloriously hued blue butterfly although it can be a rare experience to actually see the blue while the butterfly is at rest. Often their wings are held folded together above their body, with only the grey dotted undersides on display. They are common from April through early June and you can sometimes find a congregation of them sipping their mineral supplements at a mud puddle, hence the term mudpuddling. They lay their eggs on the buds of oceanspray, blueberry, spirea and red osier dogwood. According to Peterson’s First Guide to Caterpillars, the young are termed slug-like and are tended by ants for their honeydew. Having ants concerned about your welfare is a good strategy to keep predators at bay.
Lorquin's Admiral
Lorquin Admirals are usually found in edge habitats, often along hedgerows where they strongly defend their territory, males can be seen perched five metres apart, heroically ready to battle any and all intruders. These large (5.6-6.5 cm), striking, dark butterflies are brightly banded in white across their upper wings, with orange tips. From June through September, the females use willows, poplars and bitter cherry as well as orchard trees on which to lay their eggs. In the fall, the caterpillars (who appear a lot like bird droppings-another defensive measure) will roll a leaf around themselves, use their silk to attach the leaf to a branch (a better strategy than Propertius Duskeywings?) and prepare to spend the winter comfortably swinging in the breeze. If the days warm up sufficiently they will take the opportunity to graze. Adults will feed on nectar plants, fresh animal droppings and rotting fruit. I have observed them feeding on the few rotting plums the bears didn’t manage to eat…
Pine White
Pine Whites are a medium sized (4.5-5 cm) summer butterfly, superficially resembling the introduced Cabbage White. The Pine Whites have a dark border to the wings and are usually seen high in the canopy of Douglas-firs, their preferred host plant. One summer I spent quite a lot of time looking out a hospital window where I  enjoyed the slow, graceful ballet performed by the Pine Whites high amongst the trees.
Purplish Copper-female
Purplish Copper-male
Purplish Coppers on the other hand are small (2.5-3.5 cm), quick and known to be fearless, attacking larger butterflies that encroach on their territory. They are a widespread butterfly of the west.  Males and females have different colourations and sizes, the males are smaller and sport the purplish sheen that has given it their common name. The larger females are quite orange on their topwings and both sexes have a thin orange zigzag band across the bottom of their hindwings. Their host plants are sorrel, dock, smartweed and knotweed, many of which are weedy species. Purplish coppers can be found in a variety of habitats, preferring moist areas but also found on disturbed sites (the usual habitat of introduced and weedy species). They have two generations per year, and you can find them flying most of the summer with peaks in June and August.
Common Branded Skipper (ssp oregonia)
The Common Branded Skipper subspecies oregonia is a very rare, small, brown butterfly with white markings, known only from two remaining locations. One in Metchosin and another on the Peninsula. It’s host plant is believed to be some type of native grass, many of which have disappeared from the area, overwhelmed by invasive species such as broom, hairy cat’s ears and a multitude of introduced grasses. It generally flies in late July through early September , when nectar plants are in short supply-most having succumbed to drought. It will feed on pearly everlasting and our native asters as well as garden nectar plants.
I find butterflies a reason to get up in the morning, I wait in anticipation all winter for their return. The cold, wet springs that seem to be extending their season and the loss of habitat are reasons for concern for the survivability of even our more common butterflies, however stewardship options abound. Habitat protection is critical, preserving our remaining natural areas will allow butterflies and the plant species they use to continue to co-exist, especially important are open sunny areas, Garry oak woodlands and rocky hilltops. Restoration of habitat by removing broom and other invasive species supports biodiversity and allows the native plants that sustain butterflies to regain their hold on the landscape.
If you are a keen gardener, you could consider planting butterfly host and nectar plants. Butterflies seem to have a preference for nectar plants that are yellow or blue, save the reds for the hummingbirds. Plant in full sun, the butterflies will rarely venture into shade, and plant a succession of nectar bearing flowers, so there are always some plants for a stray butterfly to sip. Nectar plants should also supply nectar that is accessible, ones in which butterflies can reach the nectar with their proboscis (tongue), rhodos are useless to butterflies. The flowers also need to support the weight of the butterfly, very small flowers such as blue-eyed Mary are too minute even for a small butterfly. Some good nectar plants include asters, lilies and members of the pea family. If you have a lot of space and are unconcerned about being overrun by certain plants, both our native Douglas aster and pearly everlasting supply valuable summer and fall nectar for butterflies and many other species of insects. You will never be bored watching the flurry of winged activity around these flowers. 
Host plants also need to be planted in full sun and be large and dense enough to allow the development of the caterpillars, they can’t wither or be totally consumed before the larval development is complete.
Mylitta Crescent-female
Some butterflies appreciate patches of wet soil, for mudpuddling while others will welcome alternative food sources such as rotting fruit, sap, carrion and dung. A few species will overwinter as adults under shingles and loose pieces of bark.
These winged denizens of our open fields and wild lands have suffered severe reductions in their populations, for reasons beyond their control. Metchosin is fortunate to be home to some of the rarest species and with good stewardship we can hope to bring them back from the edge of extirpation (extinction on a local scale). Enjoy your summer and your butterflies!

No comments: