Monday, July 7, 2014

Edwards' Hairstreaks 2014

The first week of July seems to be the peak flight period for Edwards’ Hairstreak Butterflies at Blue Jay Barrens.  Because of this, it has become a Fourth of July Holiday tradition for me to take a little time to survey the Edwards’ Hairstreak population.  Of course, I also look at many other things, but for this one outing my priority is to find the hairstreaks.

I had plenty to look at.  There were dozens of Edwards’ Hairstreaks nectaring on the Butterfly Weed.  I’ve never before found so many occurrences of multiple hairstreaks on the same flower clusters.

In order to have Edwards’ Hairstreak butterflies, a site must have young oak trees to provide food for the larvae and it must have Allegheny Mound Ants, an ant species that acts as guardians for the butterflies during their early developmental stages.  Click here for more details on Edwards’ Hairstreaks at Blue Jay Barrens.

When I first discovered Edwards’ Hairstreaks at Blue Jay Barrens twenty years ago, they were located in only one small area near the center of the property.  Since that time, I’ve been encouraging oaks to colonize areas near the large ant mounds.  Young Black Jack Oaks seem to be the preferred host species, so these trees are given priority in all management activities.

I was particularly impressed by the butterfly numbers at this site.  It was nearly ten years ago when I discovered a single Edwards’ Hairstreak in this small opening.  Now there is a thriving population.  Oaks and anthills indicate that the hairstreaks are a possibility.  Add in a clump of Butterfly Weed and you have the perfect opportunity to observe this butterfly.

I’m not sure how to sex these butterflies, but I would think eggs each time I saw an individual with such a robust abdomen.  I felt like shooing her off the flower and sending her over to the tree to deposit those eggs before one of the many flower lurking predators made a meal of her.  I always have to remind myself that wild animals probably know more than I do about what they should be doing to insure future generations of their species.

A few of the hairstreaks looked like they were freshly emerged, but most had lost some of their luster and were looking slightly worn.  Damaged wings suggested probable encounters with predators.

A couple just looked downright battered.  It looks like this one has had quite a time, but it proved to be a strong flier despite the wing damage.

It’s always encouraging to see positive results from your management efforts.  I’m hoping that the Edwards’ Hairstreak population at Blue Jay Barrens continues its expansion.


  1. Hi Steve.... I love this post , with those gorgeous colors of the butterfly and the flowers ...very well coordinated : )
    Could you send on of those robust abdomen one's my way, I have plenty of young oaks around!!


  2. Hi Grace. The butterflies are moving north-east of a rate of about 100 feet per year. They should reach Maine within 400 centuries if they don't have trouble getting over the mountains.