Saturday 25 May 2019

A search for two rare butterflies

On May 17 I headed back down to Point Pelee for my last weekend of watching bird migration before my work schedule began to swing into high gear. I could have driven down to be there mid-morning on Friday but I decided to take my time and explore a few other areas on my way down. The forecast was looking sunny and warm and two rare butterfly species beckoned.

My first stop was a location in north Halton Region that is known to have a population of West Virginia Whites. This species is an uncommon resident species in Ontario, known from several widely scattered populations. It requires rich deciduous woods that contain its main footplant - Two-leaved Toothwort. West Virginia Whites only fly for a month or so in early spring and it was a species I had never searched for before since their flight period coincides with peak bird migration.

I arrived at my destination to the sound of a Yellow-throated Vireo singing from above a roadside wetland. The morning was still cool and a stubborn array of clouds just wouldn't clear away but I was hopeful that the butterflies would begin to flutter by within an hour or two as the day warmed.

Long-spurred Violet - Milton, Halton Region

Large White Trillium - Milton, Halton Region

Red Trillium - Milton, Halton Region

Downy Yellow Violet - Milton, Halton Region

Spring ephemeral wildflowers were at their peak and I thoroughly enjoyed walking along with my eyes to the ground, observing the spread of flowers in front of me. Two-leaved Toothwort, the host plant for West Virginia White, was quite common along with many other species.

Two-leaved Toothwort - Milton, Halton Region

Red Trillium - Milton, Halton Region

Canada Violet - Milton, Halton Region

Early Blue Cohosh - Milton, Halton Region

Some rustling off the path alerted me to the presence of a North American Porcupine. It took a minute before the porcupine appeared to realize that I was only six meters away, which caused it to ruffle its spines on its back and tail, and shuffle off. This was my first excellent look at a porcupine in several years. I love their spiny mohawk!

North American Porcupine - Milton, Halton Region

I walked for over two hours, enjoying the sights, sounds and smells. The clouds were long gone at this point and it was turning into one of those perfect mornings: sunny and warm (but not too warm), calm, many birds - migrant and resident species alike - singing from the canopy, flowers in bloom, no biting insects, and signs of life everywhere one looked. If only I could find a West Virginia White to make it a perfect morning.

Eastern Gartersnake - Milton, Halton Region

Unfortunately it was not to be, despite the excellent conditions, and I headed back to my car to continue on. The only butterflies I had been able to turn up were azures, an Eastern Comma and a Mourning Cloak. 

Azure sp. - Milton, Halton Region

I was about 100 meters from my car when I caught sight of a white butterfly casually flitting above a bed of wildflowers. Indeed, it was my target species. Over the next 10 minutes I followed the butterfly as it loped around, pausing periodically to rest.

West Virginia White - Milton, Halton Region

West Virginia White - Milton, Halton Region

West Virginia White looks very similar to the more widespread Mustard White, another denizen of rich deciduous woods in southern Ontario. It is best told apart from that species by the pattern of the veins on the underside of the wings. The spring form of Mustard White is quite different looking from below due to dark scaling on the veins, and shouldn't be confused with West Virginia White if one has a good look. Cabbage White, an invasive species that is one of the most common butterflies in southern Ontario, is also superficially similar to West Virginia White. The dark tips to the forewing and dark spot(s)  in the middle of the forewing on Cabbage White separate that species from West Virginia White, with its clean white wings. Cabbage White is also more likely to be found in waste areas, parklands and other open habitats.

West Virginia White - Milton, Halton Region

Spurred on by my success I returned to my car to continue my journey. I thought about heading straight to Point Pelee but decided to detour for one more special butterfly. I was feeling lucky.

For two hours I explored several tracts of land in the Long Point area, hoping to come across a rare skipper called Sleepy Duskywing. I did not have exact location information for this species but explored some general areas where I knew they were present. The day had become quite warm at this point with a breeze and butterflying was difficult. The most common species, by far, was Eastern Pine Elfin, of which I saw perhaps 15. Several American Coppers were also noted.

Eastern Pine Elfin - Norfolk County

American Copper - Norfolk County

I was not able to confirm Sleepy Duskywing but I may have seen some. White visiting one open, sandy area surrounded by oaks, I flushed at least two individual duskywings on a couple of occasions. They were both extremely skittish and difficult to stay on in flight, and I never had a confirming look through binoculars. Given the habitat and their behaviour they were likely Sleepy Duskywings. I guess I will have to return at a later date to finally nail down this species!

I watched a number of tiger beetles in a sandy patch, and took photos of several individuals. Tiger beetles are a fun group to study since they are readily observable, there is a nice variety of species in Ontario (but it is not overwhelming), and many of them have unique patterns and colors. 

Festive Tiger Beetle - Long Point area, Norfolk County

Festive Tiger Beetle - Long Point area, Norfolk County
Bronzed Tiger Beetle  - Long Point area, Norfolk County

Festive Tiger Beetle - Long Point area, Norfolk County

1 comment:

Allen Woodliffe said...

Some really cool shots of the tiger beetles, Josh....very nice to see! Also the leps, porcupine, etc. There is so much to see at this time of year!