Participants – Bill Gee
Time in 0915, time out 1815.
This was the annual bat census trip in Carroll Cave. We run this trip near the end of October every year. This year, besides counting bats, we had an additional task to exchange batteries and memory card in the bat roost detector in the Mountain Room. We also moved the bat roost detector to a new position that gives it a better view of the passage to the natural entrance.
I drove to the camping site Friday afternoon, arriving about 1615. Even though it had rained about 3 inches in the previous 7 days, the field was not soggy at all. I found two of the lawn mowers were completely upside-down, and the third had obviously been moved from where we parked them. I turned the mowers over and parked them inside of the windbreak. I found a jug of gasoline laying on its side by the silo with no cap on it. It is almost certainly no good anymore. I did not try to run the red mower, since having been upside-down it probably has been drained of its oil.
I had some trouble getting the padlock on the silo to unlock. The temperature was not low enough to freeze it, and there is no obvious damage to it. Eventually I got it to open.
Matthew arrived sometime after I went to bed. Everyone else arrived in the morning. John Roth brought a crock-pot of chili for us to enjoy after the trip. We put it in my camper and turned it on. Two other people were supposed to have made the trip. We had a message from one that she would not make it. We heard nothing from the other. She did not show up at the appointed time (0900), so we proceeded without her.
All of us have been in Carroll Cave, so it was a matter of gearing up and hitting the rope. The first person down the shaft went about 0915, and we were all in the cave by 0940. We took a group photo in the cave, then set off.
On the way down Carroll Passage I placed one of the cave intrusion detectors I have been working on for a while. I had placed one over the spring, but it did not work well. This one is an 8mhz part with newer software and better batteries. I will pick it up perhaps in March when we visit the bat roost detector again.
We went straight through the Water Barrier to the isopod test site just beyond. In spite of three inches of rain in the last seven days, the water level in the Water Barrier was no higher than usual. We counted and measured isopods for about 10 or 15 minutes, then continued on to the guano piles.
The guano piles showed the usual pattern of usage. The two biggest piles had somewhat less guano on the gauges than I have seen in the past. Normally the guages on pile 15 are completely covered to 4 or 5mm depth. This trip they were only about 80 or 90 percent covered.
We saw a lot of bat carcasses that looked fairly fresh. I took photos of some. We saw a lot of grotto salamanders around guano pile 6.
We got to the Lunch Room shortly before noon, which is 40 minutes or so earlier than usual. We stopped for a heavy snack break, then moved on to start the bat counts. We left the Lunch Room about 1215.
As has become usual, we saw almost no bats until reaching the 500 foot marker. Instead we saw sculpins in quantity! Last year (2020) we also saw quite a few sculpins in the stream. Before that, there were almost none except right around the Mountain Room. Our bat census trip turned into a sculpin census trip. We also saw quite a few larval size (2 to 3 centimeters) salamanders.
We saw one small section of the stream where the stream bed was black with guano. The area was about 6 feet long and two feet wide at the widest. I don’t remember exactly where this was. I seem to remember it being around the 3000 foot marker.
There is usually a cluster of bats just upstream of the 500 foot marker. We saw a cluster there, but it was much smaller than last year. We estimated no more than 200 (probably less) individuals. In past years this cluster has been closer to 1000 individuals. Besides this cluster, we only saw one other bat over the entire length of cave from the Lunch Room to the Mountain Room.
We arrived at the Mountain Room about 1500. After another snack break, we proceeded with more tasks. I went around and documented the state of all the guano gauges. They were, as usual, empty. John, Martin and Matthew did a concentrated critter count in the stream from one end of the Mountain Room to the other. In addition to many frogs and sculpins, we saw several trout. They ranged from about 8 to 20 centimeters in length. We have never seen trout in the cave before.
The bank of the stream in the Mountain Room had a lot of animal footprints, probably either racoon or muskrat. After the trip Martin did some searching but was unable to find an exact match. We also noticed a lot of animal scratches in the mud banks as we were doing the bat count.
Kristen and I, with some help from Matthew, placed a PVC mount bracket for the bat roost detector. We stuck it in a firm mud pile right at the stream edge. I changed batteries and memory card in the roost detector. I had to fiddle with it for ten minutes or so before it started. I suspect it might have been working, except that I was not patient enough to wait for it to complete its bootup. Once it was running, we fastened it to the platform on top of the PVC supports and aimed it at the passage to the natural entrance.
We were all getting a bit chilled, so we left for a flying trip back to the ladder. We left the Mountain Room about 1600 and arrived at the Turnpike ladder about 1620. The trip through the Turnpike took about 25 minutes. By then we were all warmed up. Continuing on, we arrived at the ladder about 1745.
Several attempts at another group photo did not work because the camera flash did not go off. We gave it up and started climbing out. Everyone was out of the cave by 1815. We pulled up the rope, locked the hatch and changed to clean clothes. John had set out a black bag of water for showers which was used by a couple of people.
The chili crock pot gave my camper a very nice smell! It was tight, but all five of us were able to get seated in my camper for a chili feast. Thanks, John! The chili hit the spot.
Martin and Matthew had things to do, so they left after dinner. John, Kristen and I camped overnight. The overnight low temperature was 36F according to my camper’s thermometer. Kristen and I got up early and were on the road before 0600.
=================== Data Section ==============
Lunch Room to 6000: count is zero for everything.
6000 – 5000: Bat count is zero. One sculpin. 3 larval salamanders, 3 to 4 cm. One cave fish.
5000 – 4500: Bat count is zero. Sixteen sculpins, 15 salamanders, one abandoned boot. An eight inch depression in the stream bed that looks like something dug it up.
4500 – 4000: Bat count is zero. Six sculpins, one salamander.
4000 – 3500: 1:45pm. One bat. Three sculpins, three adult and one larval salamander.
3500 – 3000: Zero bats, two sculpins, zero salamanders.
3000 – 2500: Zero bats, zero sculpins, zero salamanders.
2500 – 2000: Zero bats, zero sculpins, zero salamanders.
2000 – 1500: Zero bats, three sculpins, zero salamanders, one cave fish.
1500 – 1000: 2:26pm Zero bats, two sculpins, zero salamanders.
1000 – 500: Cluster of bats perhaps 100 to 200 individuals. Two sculpins, zero salamanders. The cluster has been seen in prior years, but is much smaller this year.
500 – Mountain Room: Zero bats, sculpins, salamanders.
At the Mountain Room: 3:00pm. 40 frogs in two groups. 16 sculpins, 3 trout at 25, 15 and 8 centimeters. No salamanders. No crayfish. Two bats flying. Bunch of tracks, perhaps muskrat.
All five tiles in the riffle were blank. One larval salamander
2mm = 4
3mm = 3
4mm = 1
5mm = 2
10mm = 2
Guano gauge 1 = 60% 2mm fresh fungus on both gauge and pile
Guano gauge 2 = 30% 1mm
Guano gauge 3 = Completely clean. Some fresh fungus on the overhang near the guage.
Guano gauge 4a = Completely clean
Guano gauge 4b = 80% 3mm fresh fungus on both gauge and pile, gnats on the guano. A fresh patch about 4ft by 2ft.
A dozen or so bat carcasses that look fairly fresh.
Guano gauge 5 = Completely clean
Guano gauge 6 = 30% 2mm on one side to dusting on the other. Gnats on the pile. Fresh guano on pile about 5 or 6 feet diameter.
8 grotto salamanders near pile 6. Length ranging 10 to 12 cm. One was clost to 15 cm.
More bat carcasses. One is fresh enough that the bones are still articulated.
Guano gauge 7 = Completely clean
Guano gauge 8 = Completely clean
Guano gauge 11 = Completely clean.
Guano gauge 12a = 95% 3mm fungus and fresh guano on the pile
Guano gauge 12b = 90% 3mm to about 1mm. Fresh fungus and guano about 6ft diameter
Gauno gauge 13 = 10% dusting.
Guano gauge 14a = 30% 2mm
Guano gauge 14b = 10% – a few good-size turds
Guano gauge 15a = 80% 3mm fungus and fresh guano around most of pile 15.
Guano gauge 15b = 50% 2mm
Guano gauge 16 = 20% 1mm. The first activity we have seen on this gauge in several years.
Guano gauge 30 = Completely clean
Guano gauge 31 = Completely clean
Guano gauge 32 = Light dusting of guano.
Guano gauge 33 = One turd plus a dusting. A bit of fresh guano on the pile around it. Also one bat carcass.