Thursday, July 12, 2018

Edwards' Hairstreak Butterfly Census 2018

Since I don’t actually count the butterflies or produce any type of tally, my annual observations of the Edwards’ Hairstreak Butterfly can’t really be called a census.  What I do is search appropriate habitat at Blue Jay Barrens to get an idea of current size and distribution of this uncommon butterfly.

Each year, I find butterflies in new locations and in concentrations larger than the year before.

Edwards’ Hairstreak Butterflies were quite rare when I first surveyed this property 33 years ago.  It took years before I found my first specimen.  Subsequent annual searches resulted in sightings of just a few individuals or, in some years, no sightings at all.  Now I can find that many or more sharing a single flower cluster.

One of my first management projects was to make the property more suitable to Edwards’ Hairstreaks.  I cleared Eastern Red Cedar from the fields to promote prairie like habitat, and encouraged the growth of Blackjack Oak, the Edwards’ Hairstreak preferred larval food. 

As habitat improved, the number of butterflies increased.  Nectar plants also responded to the management efforts and increased in number.  Butterfly Weed, a favorite of the hairstreaks, is now common in most areas containing butterfly colonies.

A few years ago it was uncommon to see more than a single Edwards’ Hairstreak on a clump of Butterfly Weed flowers.  Now the butterflies visit the blooms in masses.  There are 10 butterflies clearly visible nectaring on Butterfly Weed in the above photo.  There are still suitable areas not yet being utilized by the butterflies, so butterfly numbers have the potential to increase for many years yet.

The above video shows some Edwards’ Hairstreak nectaring action.  A few Honeybees are also trying grab some of the nectar.  Near the end of the video, one butterfly appears to headbutt another away from his flower cluster.  This video can be viewed on YouTube by clicking HERE.


  1. Hello, your blog is cool, thank you for taking the time to do this! I stumbled upon it trying to figure out if I had happened upon a vole/mole/mice nest and ended up reading your most recent post about the Edward Hairstreak. I Googled it after to learn more and could not find it being labeled as endangered. So, I was just curious, why did you make your property more suitable to this butterfly? Funny enough, I just got back from a talk on the Monarch and planned to put some plants in my yard for them and now I'm reading about the Edwards. Thank you from Massachusetts!

    1. Edwards' Hairstreak Butterflies are not endangered in Ohio, but they are uncommon and are associated with the barrens and dry prairies I am managing here. Clearing trees from the prairie openings would have occurred regardless of the presence of the Edwards' Hairstreaks. Leaving the oaks in the fields was the key management change resulting from the discovery of Edwards' Hairstreak populations being found here. Scroll down and click on Edwards' Hairstreak in the index list on the lower right side of the page to see earlier posts about this species.

    2. I see! Thank you for your response!

  2. Steve. It is always heartening to learn that your appropriate land management has a positive effect on certain species. You are to be congratulated on the expansion of the delightful Edwards' Hairstreak.

    Interestingly my weekly transect walks this year through ancient oak woodland has produced the highest volume of sightings of our Purple Hairstreak in any of the past four years; no doubt attributable to the recent long spell of higher temperatures. If the recording criteria permitted me to count much earlier in the morning I'm guessing the numbers would have been 'off the scale'.

    Many thanks for your recent comments and for continuing to keep a watchful eye on my blog activities.

    1. Thanks, Frank. Let's hope our butterfly populations continue to grow.