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09 May 2011 @ 08:01 am
OFNC Outing to Constance Bay – Part II  
After another stop at Jeff’s house to use the facilities and retrieve our cars, we traveled to Bishop Davis Drive in a long procession that must have bewildered the locals. Bishop Davis becomes a dirt road once it leaves the village behind, and eventually comes to a large track entering Torbolton Forest. This is a prime spot to look for the regionally uncommon Olympia Marble, a beautiful butterfly related to the more familiar Mustard and Cabbage Whites.

The Olympia Marble prefers open sandy or barren areas where rock cress, its larval host plant, occurs. With the beautiful green veining on the underside of its wings, it is unmistakable and definitely worth searching for.

Torbolton Forest sign

This was one of the species I had hoped to see on the outing, and, incredibly, one of the group members found one fluttering along the edge of the road. Jeff quickly netted it, put it in a jar, and passed it around for the group to see. Once the group had finished looking at it, he let it go, and Pat Blake and I spent some time photographing it on the ground. This is my favourite photo of the Olympia Marble.  Note the bright yellowish-green eye:

Olympia Marble

We left the butterfly to recover from its ordeal, and followed the trail through the woods to a large open meadow.  This meadow is unique in Constance Bay, as it is one of the few remaining vestiges of original habitat before development and forestation altered the landscape.  We settled in to eat our lunch, although we were distracted by a Blue-headed Vireo (my first of the year!) singing in the woods, a Broad-winged Hawk soaring across the sky, and a pair of Red-shouldered Hawks circling above the clearing.  The Red-shouldered Hawk is easily identified in flight by crescent-shaped "windows" in the wings and reddish shoulder patches.  While the Red-shouldered Hawk is a forest breeder, it is always found near water where it feeds on frogs, snakes, rodents and small birds.  In the east, it is not uncommon for the Red-shouldered Hawk to share its territory with the Barred Owl. These species prefer the same moist woodlands and feed on similar animals. However, while the hawk is active during the day, the owl hunts at night, allowing these two birds to co-exist.

While we were eating and relaxing in the warm spring sunshine, Jeff was examining the willow flowers for insects.  He found a beautiful, fresh American Lady butterfly on one willow, and several bees, hover flies and assorted insects on all of them.

American Lady

One of my favourites was the Tricolored Bumble Bee, also known as the Red-banded Bumble Bee.

Tri-coloured Bumble Bee

This insect in Jeff’s hand looks like a bee but is actually a hover fly (also called a flower fly).  Hover flies belong to the Family Syrphidae, and, as members of the Order Diptera, have a single functional pair of wings (bumble bees, on the other hand, have two pairs of wings).  They are brightly colored, with black and yellow or black and orange bands, and as a result they are often mistaken for wasps or bees.  Hover flies, however, cannot sting and are completely harmless to humans.

Criorhina species

Not only are these small flies unable to sting, they are beneficial to humans as pollinators and important natural regulators of aphid populations. Some hover flies feed on the nectar and/or pollen of flowers, some feed on dead and decaying organic matter, some feed on dung, some eat fungi, some eat plants, some are predators, and some are aquatic filter feeders.  As such, hover flies fill many a valuable ecological niche.

This is another hover fly:

Criorhina species

Surprisingly, we only came across the one butterfly in the meadow. It was a beautiful, warm day – the temperature had risen to 20°C, perfect for observing butterflies – but because of the cold, wet weather we’d had earlier this spring, the butterflies were emerging later this year. Moths, too, have been affected; however, I did come across a pair of tiny moths on one of the willow flowers.  The iridescent colours intrigued me, as did the exceptionally long antennae.  I later found out it is Adela purpurea, one of the Fairy Moths.  This species flies early in the spring and is commonly found swarming at willow flowers on sunny spring days.  This one is a male, as evidenced by the long antennae; females have much shorter antennae.

Adela purpurea moth

After about an hour of soaking up the sun, sandwiches and wildlife, it was time to move on.  Jeff planned on taking us to the Bill Mason Center next, and I was looking forward to seeing what might be around there.

Next: OFNC Outing to Constance Bay – Part III

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Soul Diasporasoul_diaspora on May 14th, 2011 03:10 am (UTC)
I'm enjoying these photos--I had originally planned on going on the Constance Bay trip but wasn't able to make it, so this way I can enjoy it vicariously :-)

I like the tricolored bumblebee, I think I saw a bumblebee like that once but mistook it for a regular bumblebee loaded down with pollen.

The Olympia Marble is fascinating, I've never seen a butterfly like that before.