Drift fence predator!

Usually I am very excited to find mammals visiting our drift fences.  We frequently deer mice and shrews in our pit fall traps and it's always fun to have something other than the expected amphibian.  A few weeks ago we even had a flying squirrel in a bucket.  Very cool.  I also like finding mammal tracks in the area, having studied gray foxes and fox squirrels for several years I especially like getting to see those, or signs of those.  But, unfortunately, the most common mammal experience we have at the drift fence is when we find toads and salamanders that have been killed by raccoons.  I love and respect raccoons, but their behavior at the drift fence just drives me nuts.  They go from bucket to bucket and bite the heads off of marbled salamanders, but don't eat them--presumably because their skins secretions make them distasteful.  Same goes for southern toads, they puncture them and maybe take some eggs out if it's a gravid female, but for the most part they just kill them.  I wouldn't mind so much (it is just part of the normalcy of nature) but they just don't seem to learn that they don't like the taste so they just keep killing a few per bucket.  So when we find that we have a raccoon "running the fence" we set traps.  Got a coon last week, and took some photos when we released it.  We just take them away from our sites and let them go in suitable coon habitat. This one was fun to watch, it ran quickly then went right up a tree, almost to the top, and just watched us for a while.  Then while leaving that area we came across a bunch of wild pigs so I'll share some photos of those next time.

Toad time

Well, the toads have been more cooperative than the leopard frogs so far.  I wouldn't exactly say they are doing just what we want, but they are at least laying eggs.  We have two separate groups doing ecotoxicology projects on southern toads right now.  A few of us are setting up a huge experiment to look at copper as I've talked about before.  Brian Metts is setting up some studies to look at coal fly ash.  Brian is wrapping up his PhD examining the effects of fly ash on amphibians and this will make the final chapter.  With the work we all are doing right now I could really relate to an article I read yesterday about being a scientist.  One quote: "My job, in essence, is to move small amounts of liquid from one place to another. That's it"can ring true when I'm doing a ton of lab work.  It's odd that I can convince myself it is more interesting to move liquid when it's DNA from a really cool species, or even more when it's RNA, but the truth is it all looks like water and I move tiny amounts of it from tube to tube.  That actually may be more exciting than what Brian gets to do right now.  For his work one of the things he needs to measure is clutch size (number of eggs a female lays) of toads.  Clutch size is one thing that can be strongly affected by exposure to contaminants so it's an important variable to measure. But measuring it really sucks.  Toads lay a lot of eggs, seriously, a lot of eggs.  Trying to count them all in one sitting you'd never keep track so he separates the clutch into 5 of more bins and takes pictures.  Toads lay their eggs in long strings so in a bin you can kind of spread them out in a way that there is just one layer of eggs, then with a photo you can count at your leisure and keep track of which you've counted.  He has to measure a lot of clutches so this will take some time.  The two pictures show two such bins.  The top one is pretty good, but counting the bottom one will be annoying b/c their not spread out into one even layer.  So, sometimes being a scientist means counting all day long for many days.  I only had to count eggs from 78 small containers today, with only about 20-30 eggs per container so no so bad!

Leopard frogs are stubborn!

Sorry for the incredibly long delay in posting.  After blogging about doing ecotox studies on amphibians the ecotox project we were trying to get started kind of took over our lives.  Thought I'd explain today how some of the best laid plans can still completely backfire.  Our goal was to set up an enormous study on southern leopard frogs.  We would have experiments in the field (the H02 constructed wetlands), nearly 400 tadpoles being reared in the lab, and 42 outdoor mesocosms too.  It's incredibly ambitious, but also a pretty cool study.  Anyway, to make this work it was critical to be able to pair a male and female together, get them to breed, and collect some of their eggs for the study.  We needed several pairs from two different locations to breed and they needed to all breed on the same night so we could start the experiments at the same time.  With many species this isn't so hard.  With leopard frogs it is a royal pain in the arse.  We knew from experience that leopard frogs could be a bit stubborn so this year we tried setting up 20 bins (each with a pair) right on the banks of one wetland where they could hear the large chorus of calling male frogs to get in the mood.  This was a pretty big undertaking, measured all of our frogs, injected them with some hormones to enhance the chance of egg laying, and got them into pairs.  then we lugged 4 50L carboys of "lab water" down to Ellenton bay, filled the bins, put the pairs in, carried them to the bank, duct taped and bungee corded the lids down to prevent raccoon predation, covered them with shade cloth and hoped for the best (the bins are pictured here).  Well, the next morning we got skunked: 0 for 20.  Gave them another night and got skunked again.  Had to make an on the fly decision and we decided to punt on the main plan, grab some fresh egg masses from the wetland at large, do a small scale study on the leopard frogs and regroup for the southern toad season.  We finished the leopard frog egg study and now we are just waiting for a big toad movement.  We've had a couple of rainy nights but so far the toads are holding out--not sure what they are waiting for, but we hope they behave better.  They usually do---I guess they aren't so finicky about their mating partners!  So, things are hopefully returning to normal and blog posts will be more regular again!