http://www.bclocalnews.com:80/vancouver ... 86349.html
Cool spring hurts butterfly population
June 26, 2008 |
Every spring butterfly enthusiasts rush outdoors with camera or binoculars in hand to document the soaring colourful insects that represent spring.
But the unseasonal cold spells and unpredictable weather patterns over the past few years have played havoc on Vancouver Island’s butterfly population.
James Miskelly, an expert on habitat restoration for endangered butterflies on Vancouver Island, said because the past few springs have been cooler it’s difficult for butterfly species that live in early spring to survive, mate and lay eggs for next year’s population.
“Adult butterflies are only active in warm, sunny weather. A butterfly that’s in a pupa since last spring, emerges on a sunny day, spreads it wings and flies around with a lifespan of only seven to 10 days, may live out its entire life cycle living under a rock because the weather is too cold,” said Miskelly. “This means that some species won’t mate and lay eggs as expected.”
The result? A smaller number of butterflies hatching the next year.
Seasonal temperatures also affect the host plants that butterflies live off: if there is nothing for them to eat, they die.
The Natural History Society has been conducting butterfly counts since the early 1990s. From April to September, more than 50 volunteers look for different species of butterflies and report their findings back to Miskelly, who has been the co-ordinator for the last four years.
The statistics show the species that are most active in early spring have been steadily declining. In 2005 by the end of March, 11 different species had been seen on Vancouver Island as compared to only four this year.
Miskelly also attributes habitat destruction created by urban growth as another major problem affecting the butterfly population.
Jeremy Tatum, 73, a retired University of Victoria physics professor, is on the committee conducting the butterfly count. Tatum has been a butterfly enthusiast for 71 years.
He said this year is the worst he’s seen in the butterfly population.
Tatum went out walking in search of butterflies Tuesday for three hours and didn’t see a single one.
He blames the cold spring, but also the gypsy moth pesticide that was sprayed last year.
“The spraying for the gypsy moth can only be harmful as the bacterium is harmful for all butterflies,” said Tatum.
Annie Pang frequents Seymour Hill, Mount Tolmie, Swan Lake, Esquimalt Gorge Park, Beaver Lake and countless other parks in search of her passion – photographing butterflies.
She has lent a photographic butterfly display to the Swan Lake Nature Sanctuary House to help educate children and visitors about the different species of butterflies that live on Vancouver Island. The display is unique because Pang accompanies her photos with poetry she writes about the butterflies.
Pang said the pale swallowtails, sara orange tips, western tiger swallowtail and the blue azure were all late this year.
“When you see a butterfly with wings open, they are trying to warm up their wings before flying. If they can’t fly they are easy targets for birds,” she said.
She found a western tiger swallowtail, Vancouver Island’s largest butterfly, on her back porch. It was cold and windy so she covered it with a pot and a rock and waited for the sun to warm it sufficiently until she could release the pot and let it safely flutter away.
“I’m taking as many pictures as I can and saving them on a hard drive because I’m worried the day will come when there aren’t any more butterflies,” said Pang.
“I’m upset because there is nothing like seeing the real thing alive and moving, butterflies are poetry in motion and are irreplaceable,” said Pang.