29 April 2012

A "tidal wave" of Red Admiral butterflies


Much of eastern North America is experiencing a sudden abundance of a particular butterfly - the Red Admiral (Vanessa atalanta).  Population "explosions" have been reported in the past, but the current one is awesome in its size.  Here's a report by a knowledgeable observer in southeastern Wisconsin:
I looked down Hwy 14 with 8.5x binoculars (50 degree field) to a sign that was 1/5 mile away. I counted 61 Red Admirals crossing the road, heading north, in 60 seconds! Calculations are precarious but fun: that's 305 butterflies per mile per minute. Wisconsin's south. boundary is 149 miles wide. That's 45,563 butterflies streaming into the state each minute, or 2.7 million Red Admirals per hour.
The extrapolation is, of course, tongue-in-cheek, but his report has been echoed by observers all across Wisconsin.  And today I found this report from Canada:
Eastern Canada is in the midst of what’s believed to be the biggest springtime butterfly migration in history. Hundreds of thousands of butterflies have made their way north — many more than usual and much earlier than expected...

Glenn Richardson, president of the Toronto Entomologists’ Association who’s been observing butterflies since the late 1960s, called it “the largest migration that I’ve ever seen.” He estimates the population is 20 times higher than usual...

Although it’s difficult to pin down exact numbers, Kerr said there could be millions of butterflies across Eastern Canada. Larrivée said one man found an estimated 20,000 butterflies in the backyard of his London, Ont. home and there are other reports of butterfly-covered trees. 

14 comments:

  1. If you have to have an "infestation" of some kind, I suppose this is one of the best!

    ReplyDelete
    Replies
    1. Not only that - their favored host plant is stinging nettles, so that's what their caterpillars eat, and no one complains about that.

      Delete
  2. That top one looks for all the world like someone set a flame in the center and the ember is working its way slowly out to engulf the wing tips, leaving ash behind. Nature's designs are amazing.

    ReplyDelete
  3. I've noticed the explosion of Admirals here in Tx too.
    On a huge blooming privit hedge I happened to be standing beside for an hour I lost count of the admerals and over 15 buckeyes. I also noted the lack of honeybees (only 3 or 4) 1 bumblebee, very, very few hairstreaks (2 or 3) or skippers (1), and a decent smattering of hackberry butterflies and sulphers. I can only compare it to the snout nosed butterfly explosion in the Austin area in '98 ('99?)

    ReplyDelete
    Replies
    1. Snouts are hard to find up here; I can remember spotting only one in the past three years. You are blessed with a wide variety of microenvironments in Texas, which is probably one reason NABA built their National Butterfly Center there.

      http://www.nationalbutterflycenter.org/

      Delete
  4. Ah Ha! Don't know much about butterflies (but thanks to TYWKIWDBI, learning more) but we have seen a lot of these beautiful butterflies here in the Lansing MI area as of late. Moreso than usual - a nice treat!

    ReplyDelete
  5. Large migration here in Northwest Penna. also! Really cool! I'm talkin' hundreds throughout the day....not thousands or millions but that is way, way more than I have ever seen any other spring. All are headed south to north.

    ReplyDelete
  6. There are about six red admirals in my courtyard (a brick condo building in Oak Park IL) where I've never seen any before, and in particular, one couple that land on the side of the building about the second floor and rise to the top of the 4 story tree, then back down and around during their chase. Fascinating!

    ReplyDelete
    Replies
    1. That's probably their mating dance, if they're spiraling around each other in flight.

      Delete
  7. Here in Ashville New York the weather got up into the eighty's and tens of thousands of Red Admirls were visiting my Blueberry farm. First time we ever noticed the butterfly in such great numbers

    The Blueberry Patch
    Dave Smith

    ReplyDelete
  8. Saw one today in NE Ohio. I knew what it was because of this blog. :)

    ReplyDelete
    Replies
    1. Good. Now, next time you have an over-ripe black banana, set it out. but it open, and see what happens...

      Delete
  9. Traveling by car from upstate NY (Lake Ontario) to Philadelphia today we encountered a surprising number of red admirals. Quite a few adorned our windshield but many more survived to wing their way north. We noticed the number of butterflies declined as we passed Allentown. Thanks to this blog I could identify the species and marvel at the migration with a bit more understanding. Thanks.

    ReplyDelete
  10. Thank God I found this site...they have landed and are hanging on the front stones of my tudor home! We were not sure if it was the new plants we planted or something else. They are all over our property and hang everywhere! Beautiful but scary to see if you are not used to it! We are in Westchester county...1/2 hour outside NYC...

    ReplyDelete

Related Posts Plugin for WordPress, Blogger...