CVC Butterfly Blitz's News

July 12, 2019

Observation of the week – July 6-12, 2019

Our third observation of the week is this Eyed Brown seen by user @reuvenm: This observation is one of only three Eyed Browns on iNaturalist seen in the Credit River Watershed!

Reuven (aka @reuvenm) is currently in the lead for highest number of observations in the Butterfly Blitz – with 44 to date. He is an accomplished naturalist with extensive knowledge of the watershed, having previously worked for CVC doing natural areas surveys.

This Eyed Brown observation was no accident – Reuven went looking for it:
“For the butterfly blitz, I wanted to make a special effort to find some of our species that specialize in high-quality marsh habitats.

“I've previously encountered mostly small remaining areas of such habitat at Erindale Park in Mississauga and some sites in Caledon, but didn't know of any sizable areas within the watershed that were readily accessible to the public. Doing some research, the trails at Alton Grange looked good and last Saturday I headed out to see what I could find. Turns out that there is some excellent marsh habitat there! Despite extremely muggy, overcast weather, I was successful in finding numerous Eyed Brown among several other notable butterflies […]. I definitely intend to return to this spot very soon in better weather in search of other marsh butterflies that might be there like Baltimore Checkerspot, Silver-bordered Fritillary, Bronze Copper, Black Dash or Mulberry Wing.”

If you know where to look, the Eyed Brown can be quite locally abundant, even though it is not a particularly common or widespread butterfly in the Credit River Watershed. The caterpillars of Eyed Brown feed on native sedges, and the adults feed on nectar plants like Swamp Milkweed and Joe-Pye Weed. Many of the wetlands that supported these species have been lost from southern Ontario.

The conservation status of the Eyed Brown has been assessed as secure both provincially and nationally; however, this species may be a local species of conservation concern. A quick look at the Ontario Butterfly Atlas shows that there were many more observations of the Eyed Brown in our area in earlier decades, when wetland habitat was more abundant: Currently, it seems restricted to the few high-quality patches that remain.

With the help of all the wonderful citizen scientists participating in the Butterfly Blitz, we aim to collect the data necessary to complete local conservation status assessments for all butterflies in the watershed within the next few years. So, please continue getting out there and looking for butterflies – your efforts will be put to good use!

Posted on July 12, 2019 17:43 by lltimms lltimms | 0 comments | Leave a comment

July 09, 2019

Observation of the week – June 29 to July 5, 2019

Our second observation of the week is this lovely shot of a Hobomok Skipper feeding on bladder campion by user @bob15noble:

I love how you can see the proboscis ("tongue”) of the butterfly extended into the flower, and all of the little details on the wings and body. It’s no surprise that this picture is such a good one; Bob (aka @bob15noble) is known for his excellent macrophotography skills and has contributed over 2600 observations to iNaturalist.

Bob saw this skipper during the one-day butterfly count on June 29th, on the Elora Cataract Trail just west of Shaw’s Creek Road. About the observation, Bob says: “I originally thought that it was some kind of Duskywing but wasn't sure of the ID, so I wanted to be sure that I got a picture. It was feeding so it wasn't as skittish as it could be. When it did settle on the Campion I managed to get a couple of good shots from a low angle.”

Later on, Bob was able to use his picture to refine his identification, saying “I realized that it was a dark form of the Hobomok Skipper known as Pocahontas that only occurs in females”.

This colour variation is relatively uncommon. To see how different the two forms are, check out this observation of a Hobomok Skipper with the more common colouring, also seen by Bob in the same area:

The one-day butterfly count was a resounding success. Eighteen butterfly blitzers went out and visited nine different sites. In total, they observed 476 butterflies from 26 different species – including a few that have not been seen (yet) by our iNaturalist users. The data will be contributed to the North American Butterfly Association butterfly count program ( With replication over time, it will provide useful information on population trends in our area.

Thanks to everyone who participated in the one-day count, and to all that continue to add observations to our project. Happy blitzing!

Posted on July 09, 2019 17:23 by lltimms lltimms | 0 comments | Leave a comment

June 28, 2019

Observation of the week – June 22-28, 2019

Our first observation of the week is a big one – literally! This Eastern Giant Swallowtail ( was seen by user @kbann in her backyard in Erin Township.

The Eastern Giant Swallowtail is the largest butterfly species in Canada. Karen (aka @kbann) says she noticed the butterfly out of the corner of her eye as it was flying around her yard and thought at first that it was a black swallowtail, but really big – “the size of a small bird”. She wanted to get a picture to add to our Butterfly Blitz project, so began to chase the butterfly around.

Anyone who’s ever tried to get a picture of swallowtail knows that they don’t often sit still, and that they have an annoying habit of swooping up over a tree just as you catch up to them. Karen’s yard includes a mix of native trees, shrubs and pollinator plants alongside traditional garden perennials, and the swallowtail proceeded to visit almost all of them in quick succession – never stopping long enough for Karen to get a good shot.

But persistence paid off. Karen says: “I chased it into a patch of wildflowers and long grass, where it slowed down a bit”. She was then able to get a bunch of pictures, including one with its wings open.

Eastern Giant Swallowtails are uncommon in the Credit River Watershed, which is at the northern edge of its range and contains few of the host plants its larvae need – hop trees and prickly ash. However, there is some evidence that this species is becoming more common in northern areas. Perhaps sightings of this giant beauty will become a more frequent event.

Here are two short posts with more information about the Eastern Giant Swallowtail in our area:

Posted on June 28, 2019 21:36 by lltimms lltimms | 0 comments | Leave a comment

June 24, 2019

The 2019 CVC Butterfly Blitz is underway!

Hello butterfly blitzers!

We had a wonderful kick off event at Riverwood on Saturday, and the blitz is officially on. Since Saturday we’ve had 21 observations made of 16 different species – way to go!

Whether you were able to join us on Saturday or not, we are looking forward to seeing your observations throughout the summer.

You might notice that the stats for the Butterfly Blitz project include observations made as early as April 15th of this year. We have used that starting date because we wanted to capture as much of the full butterfly season in our data as possible. But rest assured, when it comes to counting observations to tally numbers for prizes and awards at the end of the summer, we will only use data from June 22nd – August 24th.

Did someone say prizes? Yes – we will be handing out prizes for several different categories at our wrap up event on August 24th. This will include prizes for the participant with the most observations, the most species, the rarest species, and others. There will also be a lucky day prize – we will choose a day between June 22nd and August 24th, and anyone who makes an observation on that day will be entered into a draw for that prize. Stay tuned for more details on our wrap up event as the summer progresses.

In the meantime, there are a few ways you can help build our butterfly blitz community online. If you see an observation with picture that you really love or a find that you think is really neat, give it a ‘fave’ (top right, under the map) or leave a comment to let the observer know. If you have questions about how someone identified a species, leave a comment to ask your question and we’ll do our best to answer. And most importantly, get outside and start taking butterfly pictures!

Thanks, and happy butterflying!

Posted on June 24, 2019 13:00 by lltimms lltimms | 0 comments | Leave a comment

May 13, 2019

Why are Butterflies Important?

Butterflies help biodiversity. As caterpillars, they feed on a single species or closely-related plants. Plants must evolve defenses to survive predators, but caterpillars will adapt to overcome them. The continuing battle causes more species variation and greater biodiversity.

Butterflies are ecological indicators and can be useful for monitoring ecosystem health and restoration success. Areas rich in butterflies are generally rich in other invertebrates. This provides a wide range of environmental benefits including pollination and natural pest control.

Butterflies are an important food source for other insects, birds, bats and other insectivorous animals (an animal that eats insects).

Butterflies have been used by ecologists as model organisms to study the impact of habitat loss, fragmentation and climate change.

Populations of butterflies and other insects face numerous threats and are declining worldwide. But, we still don’t know enough about most of them to assess the extent of the decline. We need more data!

Posted on May 13, 2019 18:47 by lchung lchung | 0 comments | Leave a comment