I hear Cricket Frogs (everywhere)

Well it’s been a while since my last post.  This research is keeping me very busy.  During the afternoon I study maps and plan out the routes we take at night, as well as searching for new places to look for frogs.   At night we usually catch the Jamestown Ferry to reach our field sites, and we drive around for sometimes 6 hours a night.   Then we get home at 2 or 3am, fall in bed, and sleep until noon.  Funny how being a college student makes this the perfect schedule.  For once I actually have a perfectly legitimate excuse to stay up very late and sleep in!

Since my last post, Jonathan acquired a brand new recorder and microphone for us.  For every site we stop at now, we take a several minute recording.  We have even re-visited many of our previous sites to get recordings for our records.  For the first few weeks of research we were covering the Penninsula–the areas between Williamsburg and Richmond.  Now we have moved south of the James River and we’re working on thoroughly covering the space in a wide diagonal transect between the Great Dismal Swamp and Petersburg.

The days have really started to blur together, so I would be hard-pressed to give you a day-by-day account of my experiences so far (at least without the notes in the field notebook).  But I will do my best to give a thorough summary.  At the end of the week before last, we drove down to Petersburg to cover some sites just south of Richmond.  We drove around areas that I have been staring at on maps for months now.  We hit some good sites with Northern Cricket Frogs near I95 before driving around Pocahontas State Park to hit a few more.  We were just about to head home after stopping near a small pond by a road when Jonathan braked hard.  I didn’t know why until he put up a hand to quiet me.  He had heard it.  A lonely Southern Cricket frog calling from among the Northern chorus.  [insert dramatic music here]

None of us had really expected to find Southern Cricket Frogs this far West.  But there he was, clear as day, calling for all he was worth.  Morphologically, Northern and Southern Cricket frogs are extremely difficult to tell apart.  There are virtually no reliable physical characteristics that can be used to distinguish one from the other.  The best you can do is go by shaky morphological tendencies that often vary from region to region.  Most people however, also can’t tell apart the calls of Acris crepitans and Acris gryllus.  The calls of the two species are similar, but they are actually entirely distinct from one another. Below is a picture of the clicks that cricket frogs emit.  The clicks of a Northern Cricket Frog are spaced out so it sounds like someone hitting marbles together, or like those magnet stones you can buy at amusement parks (you know the ones you can throw in the air and they’ll clack together).  The Southern Cricket Frog clicks are more rapid, so you can barely distinguish the individual clicks from one another, so it ends up sounding like an annoyed duck that swallowed too much helium.

Northern CF is on the left, Southern is on the right.

Northern CF is on the left, Southern is on the right.

…And that’s how we knew we’d heard our first Southern Cricket Frog of the season. To prove it, we got a recording that looks like the ones above.

That weekend we went down to Jonathan’s family farm so that we could spend two nights combing the Great Dismal Swamp for Cricket Frogs.  On Friday night we drove along the ditches West of Lake Drummond.  What we didn’t expect is the virtually nonstop Southern Cricket Frog chorus stretching from the lake all the way out to the fringes of the swamp.  We didn’t hear a single Northern Cricket Frog all night.  The next night in the Wildlife Refuge was a little slower going, but much of the same–Southern Cricket Frogs everywhere.  On a completely unrelated note, the weirdest thing happened to us as we were driving out of the Refuge.  As we drove down the road we came upon a young (very confused) buck.  When most deer get caught in the headlights on the road, they do their best to get off the road.   This one, however, took off straight down the road.  We followed it at a safe distance, waiting for it to get off the road, but it didn’t.  So we stopped, turned off the lights, and let it get a ways ahead of us before following again.  When we saw it again we realized that it had not only stopped, it had started running in the other direction–straight at us.  Then it freaked again and ran away.  This happened probably five or six times.  The last time it came at us, it didn’t stop in time and rammed the front of the car head-on.  Eventually we got it to pass us in the other direction and disappear into the bush.

The results of the Great Dismal Swamp and the Petersburg data collections are important because they tell us that somewhere in the transect between the two locations, a turnover happens between the distributions of the two species of frogs.  The past two weeks we have been working on filling in that transect.  Last week we spent three nights collecting data in Piney Grove Preserve, a pine savanna habitat that’s maintained for Red Cockaded Woodpeckers.  Most of the sites we saw in Piney Grove contained level three choruses of Southern Cricket Frogs with just a few Northerns mixed in (chorus strength is numbered 1-3, one being intermittent with few individuals, and three being hefty nonstop choruses) . We did, however, find two primarily Northern sites–a cattle pond on a pasture and a puddle in a rut on the side of the road.  On a side note, I saw my first Pinewooods Tree frog.  They sound like a car being started when they call, and they are about two inches long with a boring gray color.  But, like many other chorus frogs, if you just watch them when they stretch out their back legs, you’ll notice a brilliant stripe of color, in this case, yellow polka dots on black, on the backside of their thigh.  We got pictures 😉

This week we spent two days driving through the area between Piney Grove and Suffolk, finding mostly Southern Cricket Frogs and several mixed choruses.  The second night I finally got my picture with a frog on my face.  Cope’s Grey Tree Frogs have very sticky fingers, and they will stick right on your face if you set them there.  I also found my first Narromouth Toad, a froggy looking thing that sounds almost exactly like a Fowler’s Toad, but slightly higher pitched and more nasal.  That night we hit a raccoon halfway through the night.  Jonathan is almost always fantastic about dodging animals that get in the way.  In my weeks of working with him we have not hit anything, dodging around skunks, deer, raccoons, cats, possums, mice, and hundreds of frogs. I guess when you have so many opportunities to hit something, it’s bound to happen eventually.  🙁

Last night was our most productive night on record. We caught the 8pm ferry across the James, and fed the gulls old hamburger buns on the way.  We had our first three or four sites before 10pm.   Despite the relatively cool and dry weather, the cricket frogs were everywhere.  We heard several hefty northern cricket frog choruses in wetlands surrounded by hardwoods.  We also definitely began to notice that Northerns tend to be more dominant in areas where hardwoods are prevalent.  In piney areas, however, we always found more Southerns.  This is just a hypothesis based on loose data, but we did begin to take note of all the vegetation in all the wetlands we visited.  As a delightful double surprise, we finally found ripe blackberries and wild blueberries to guzzle at two separate sites.  We also found and photographed a fat jewel spider sitting on its net over the blackberry bushes.  We have become so efficient that last night we covered 17 new sites in less than four hours.  On a regular night we rarely break nine.  Our last site of the night on Warwick Swamp was the 100th site of the season.

One amusing side effect of this kind of work is you become very finely tuned to the sound of the frogs you are searching for.  I have begun to hear cricket frog choruses everywhere.  In fact, most machinery, such as the car, the air conditioning, etc., has a weird high-pitched overtone that sounds exactly like a distant cricket frog chorus.  Often I’m in bed at night and I know there are no frogs around but I can’t help but hear them anyways.  You also start comparing everyday sounds with the sounds of frog calls.  Fowlers toads sound like a bad fire alarm.  Cricket frogs, as i mentioned before, sound like stones or marbles being clacked together.  Green frogs sound like the release of a bowstring or a stringed instrument.  Bullfrogs sound like…..bullfrogs.

I’m just rambling now.  Enjoy the Pictures! 🙂

Green Tree Frog

Green Tree Frog

Cope's Grey Tree Frog

Cope's Grey Tree Frog

Fowler's Toad

Fowler's Toad

We are cool

We are cool

Osprey from the Ferry

Osprey from the Ferry

Pinewoods Tree Frog

Pinewoods Tree Frog

Female Cricket Frog

Female Cricket Frog

Cricket Frog

Cricket Frog