Friday, May 4, 2012

A Million Butterflies Per Hour

[Red Admiral on my truck hood, Del Haven, NJ yesterday.]

Bear with me while we do some math.

I handed Tiffany Kersten a clicker on the way home from work today, to click butterflies along the Garden State Parkway from the exit for Forsythe NWR where we work (mile 40) to mile 6, our exit. There's been an amazing movement of butterflies, primarily Red Admirals, and it should be quantified. The butterflies have been apparently flying up from the south, coming in off the ocean, and flying in a generally west-northwest direction.

Tiff clicked 652 butterflies in the 34 miles, or 19 per mile. Let's say 20 to keep the math simple.

We figure we had a 3 second window to count individual butterflies from a vehicle moving at 70 mph. In other words, a car 3 seconds behind us would be counting new butterflies. In other words, 400 butterflies per minute per mile were crossing the parkway.

Let's say this movement extended from Forsythe to Cape May, about 40 miles. That's 16,000 butterflies per minute, 960,000 per hour.

Okay, it's not quite a million. But if the movement lasted three hours (or more, as it apparently did) several million butterflies passed through southern NJ today!

Next math question: how much butterfly mass (weight) did that involve?


  1. Don,
    I found this post on Jack Conor's blog. In addition to all your other talents, I didn't know you were a mathematician too!

    I hope you don't mind, but I would like to share your info with my class. They won't get the math as they are only 4th graders, but the numbers of butterflies will blow them away! (we've been counting them in school, too)

    See you soon!

    1. Sure thing, Mary! It was an mind-boggling event, thanks for sharing the wonder with your class.