Friday, January 22, 2016

Where does an Eastern box turtle go in the winter?



Two years ago, I decided to put radio transmitters on Eastern box turtles to track their movements, and use this as an educational tool with our Science Camps.  These transmitters were leftover from a previous project and had very little battery life left in them.  So instead of throwing them away, I thought it would be a fun way to learn a little bit about box turtle home ranges.  The students use a Yagi antenna and go in search of the turtle, and if found we would weigh it, record its sex and GPS where it was found.  Following individual box turtles has been interesting to say the least.  Sometimes they would not move for over a week, then all of a sudden travel a few hundred yards in a couple days.  Most days we would find the turtle we were after, some days it would be hidden so well that a half a dozen of us could not find it, even though the receiver attached to the antenna was beeping loudly (which meant we were close).

Student using antenna to track box turtles

In the winter of 2014-2015, I was lucky enough to find a turtle (EOA-2 it was labeled, but I call him Hoffa since he is hard to find) buried in the soil in its hibernation spot.  This was great because I had never seen where a turtle chose to spend the winter.  Nor did I know how deep into the ground it would go.  I was surprised to see that not all of the shell is under soil.  It must be deep enough to stay a constant temperature, warm enough to prevent freezing.  It was burrowed in a depressed part of the ground where a tree root had rotted.  The top of its shell was exposed and only leaf litter covered that part.  I don't know how it managed to cover itself with leaves like a blanket.  I guess it was that year's leaf fall from the trees. 
EOA-2 or "Hoffa" getting a new transmitter attached and weighing in at 442 grams
 In April of 2015 Hoffa (EOA-2) came out of his hole in the ground and moved about again.  Throughout the summer, Science Camp students tracked him again, giving us an idea of his home range.   One day, they went in search of Hoffa but they could not hear his "beep".  Each turtle has a frequency number associated with its transmitter that will beep when its number is plugged into the receiver.  And if it gets too far away, over a big hill or the battery dies, you will not hear a beep.  After weeks of searching and listening for the beep, we figured our time with Hoffa was over.  The battery must have died and I figured one day we will stumble upon him and take off the dead receiver.  Months went by and this did not happen.  So goes nature.
 
Some points where EOA-2 traveled in 2 years. Green tacks show where turtle was found.  Range measures 1500 ft. X 500 ft.
A few weeks ago, In December, I was thinking about Hoffa, and where he would hibernate this winter.  Some reptiles, like many snakes, hibernate in the same place each year, could Hoffa do the same?  How specific are box turtles to their winter burrows?  When I got to work, I went to the area he was hibernating in last winter. I re-found a tree that I thought he was near last year, and it had a depressed area where a tree root had rotted.  This was the same area as before.  I raked away some leaves and unbelievably, there was about 2 inches of a turtles shell showing through the soil.  I couldn't believe it, but there was a turtle, in the exact same spot as last year.  I dug a little bit of soil out to see if there was a transmitter, and it was there, still attached.  It was Hoffa.
"Hoffa" buried in the same location as last winter
Now, this may or may not be common knowledge to Herpetologists, but I did not know a turtle would return to the same location each year to hibernate.  At least this turtle did, 2 years in a row.  This March I will put a new transmitter on Hoffa, and hopefully we will get to track him for a third year, and just maybe, he will go back to this same root hole to hibernate.

Posted by: Mark Zloba


Thursday, January 7, 2016

Spiny oak slug caterpillar video

 
Sometimes we find things that just don't look like the books tell us they should.  This caterpillar is usually not this color, and usually not found on lichens on a black walnut tree.  But there it was one September day.
  If you feel like sitting back and enjoying life at a caterpillar's pace you might enjoy this video of the spiny oak slug.
 
video

Posted by: Mark Zloba