Night Flood

Mid-April Flood in Crabhaul Swamp and the Vernal Pool

Hobcaw Barony

Georgetown SC.

April 13, 2024

7:00 PM, 65° F

Clear, no breeze

We didn’t need to go far to find some good wet spots- the road out to Crabhaul swamp was more of a stream most of the way. The swamps have been holding a lot of water this spring, seemingly more than I remember from previous years. Has it been a particularly wet spring? Let’s look at the data…

Monthly rain totals so far this spring compared to the 15 year-average.

The 15-year averages for November through March, as recorded at the Georgetown County Airport (USC00383470), are shown in the line above. The bars show the monthly totals for 2024. Data are from the NOAA National Centers for Environmental Information U.S. Climate Normals Quick Access tool which provides graphs and tables of average temperature, precipitation, and snowfall at more than 15,000 U.S. observation stations. The giant bar for December is due to mostly one day, December 18th, when we had 11.75 inches of rain. That was followed by a slightly dry January, then an about average February, but March was much wetter. I suspect that the ground water in the swamps had not receded from the December event when we got the rain in March. It will be interesting to see what the rest of the spring holds.

Southern cricket frog, Acris gryllus, in Crabhaul swamp.

Maybe it will be a good year for frogs with all this rain. There we lots of these ridiculously cute little guys singing in Crabhaul swamp. It is amazing how such a little creature can make such a big sound. Does it sound like a cricket? I think it has an acoustic sound like someone hitting two sticks together.

This was about knee deep water in the swamp, but these guys can float on rafts of grasses. They are very small, only 0.5 to 1.5 inches long, and sometime impossible to find, even when you here them calling close by. They have a Y pattern on their back, and are fairly ‘bumpy’. They eat mainly flies, spiders, beetles and other small insects.

Pine Woods Treefrog, Hyla femoralis, at Crabhaul Swamp

At first glance I called this guy a Cope’s Grey Treefrog, but upon review (with guidance from iNaturalist) I am thinking it is actually a Pine Woods Treefrog. I did not have a chance to take a peek at the insides of the thighs to see if there were distinctive orange (or whitish yellow) spots. I need to remember to look at the thighs first, as this seems to be often the needed clue for identification in frogs. The tininess of this frog (he is on a fingertip in this image), the lack of a conspicuous white patch under the eye (as a Cope’s Grey would have) and the distinct line through the eye are making me lean towards Pine Woods.

Oak Woodlouse, Porcellionides virgatus

It was mostly a night of invertebrate finds. This Oak Woodlouse (pillbug) looks like a beetle, but actually woodlice are not insects but crustaceans and are related to crabs and lobsters. Although the term ‘louse’ generally refers to something being parasitic, they are not, although they do like wood. They eat rotting plants, fungi, and, yes, sometimes their own feces. But look how intricate that pattern on the shell is!

A beetle.

Here is an actual beetle, although I don’t know which one. There are a lot of them, after all, about 400,000 described species. This is 40% of described insects, and 25% of all known animal species. Beetles can generally be identified from other insects by their front pair of wings which are hardened into wing-cases, called elytra.

Uhler's Giant Water Bug, Lethocerus uhleri

This one is not a beetle, but a true bug. In Entomology-world, the term ‘bug’ refers only to the order Hemiptera, and shall not be applied to other arthropods or insects of other orders such as ants, bees, beetles, or butterflies. This is one of the giant water bugs, commonly referred to as toe-biters, alligator ticks, or alligator flea (in Florida). Note we did not pick him up from the net for photographing. One description I found states, “The frontal legs are modified into raptorial appendages…” (emphasis mine). Furthermore, “Once caught, the prey are stabbed with their proboscis and a powerful proteolytic saliva is injected, allowing the Belostomatid to suck out the liquefied remains..” We’ll just put him back now.

Cattail Toothpick Grasshopper, Leptysma marginicollis

Here is a different life strategy. Rather than being big and scary, this grasshopper tries to…well, look like a piece of grass.

Stretch Spiders, Genus Tetragnatha

At the vernal pool I saw some drama play out. These two spiders were engaged in fierce battle, ending with one dropping into the water. I’m not sure of the species, but I believe these are in the genus of ‘stretch spiders’ which seems an apt description. According to Wikipedia, “Tetragnatha species are hard to separate from each other without a microscope to scrutinize the genitalia of a mature individual.” I’m not going to go that far to get an ID. I have seen them do the thing where they hide on blades of grass by stretching their front legs forward and the others behind them. There are tons of them in the swamp, so no wonder there are neighborhood disputes.

Six-spotted Fishing Spider Dolomedes triton

There is always a fishing spider to be found in the swamp. Just shine your light down into any pool of water, or at the base of a tree or piling, and look for the eyes. Eight of them. The better to see their prey with, which includes terrestrial insects that have fallen into the water, tadpoles, frogs, and small fish up to five times their body size. They are one of the few spider species known to feed on vertebrate species

Not a spider, but it does have kind of a ‘spidery’ look. Just to end on a pretty note, here is an iris in the night.