Biology: 2007 bat census

Trip Report – Carroll Cave Biology Project

Trip date: 13 October 2007

Participants: Bill Gee (trip leader)
Andy Isbell
Jim Cooley
Craig Hines

Time in cave: 10:00am
Time out: 9:30pm

Area visited: Carroll passage to the Mountain Room
Purpose: Annual bat census


Craig Hines rode with me to the schoolhouse where we met Jim Cooley. Andy Isbell came down Saturday morning. We were all up at the silo by shortly after nine getting dressed and rigging the drop.

As we were dropping into the cave, Spike Crews and some other people who I don’t know showed up. They were planning some survey mop-up in upper Thunder River around the Second Azure Pool. Spike and I made arrangements on how to handle the ropes depending on which team came out first. My rope was already in the hole. Spike said he would anchor a second rope but not drop it. If we came out first, we could pull my rope and drop his. If he came out first, he would remove his rope.

The four of us were all in the cave by 10:00am. The first thing we did was replace the water level logger in the stream. The old one was defective. We also did data downloads on both data loggers.

Next we stopped at the first two bait sticks which are located just 30 feet from the ladder. Both bait sticks had a lot of activity on them. There were numerous very small white insects less than 0.5mm long. I think they were springtails. We saw a few brown beetles, species unknown.

The two bait sticks under the boxwork also had quite a bit of activity on them. Again there were a lot of very small white insects and some brown beetles. The small brown beetles looked a lot like seed ticks.

A few hundred feet down the cave we had to stop for a few minutes so Jim Cooley could take off his wetsuit top. He bought a 5mm 2-piece wetsuit consisting of a Farmer John bottom and a full jacket top. It was enough to get him roasting! He strapped the top to his pack and we continued caving.

Just before the Water Barrier is another pair of bait sticks. We stopped and checked them out. They had springtails and beetles, all under 1mm long. We also saw some interesting fungus on one that almost looked like roots. This pair of sticks had some larger insects in the 1 to 2 mm range. There was one millipede perhaps 25mm long.

Near the Totem Pole about 200 feet upstream from the bait sticks at the Water Barrier we saw a fish in the stream. It was a surface fish, a bit over 6 inches long. We think it was a perch, but are not sure. It was extremely emaciated and probably will not live much longer. I took several pictures of it. It has to have got in during some flooding since there are several riffles where the water is only an inch or two deep, not nearly enough for so large a fish to swim in.

At the entrance to the water barrier we saw a small salamander, probably a grotto but too young to be sure. It was only a couple of inches long. We saw two more salamanders at the downstream end of the Water Barrier.

While going through the Water Barrier we noticed that the water level is down several inches. It normally runs about 5 or 6 inches below the shelf. When we were there it was about 8 inches below the shelf.

We stopped at a suitable riffle in the stream and did an isopod count. This riffle is about 200 feet downstream from the Water Barrier and a short distance downstream from CR2. We marked it with a blue reflector. This riffle will be repeatedly visited.

Craig and I turned over rocks to count and measure isopods. Andy and Jim took notes. Andy took notes on his voice recorder and Jim used a notebook. We counted 79 isopods ranging from 2 to 10 mm long. Most were in the range of 3 to 5 mm. Practically every rock we turned over had isopods on it. After completing the isopod count we searched for snails. None were found.

At the first set of guano piles I documented the state of the guano gauges. Andy, Jim and Craig went to look for spiders and other critters. Andy found a spider on a web in a crease in a rock. I took several pictures of the spider. The spider was about 2mm on the body and 5mm across the feet.

Guano pile 2 had a number of insects on it. One kind was a light brown beetle with a lighter area on its top, about 2 or 2.5 mm long. Another was a kind of gnat with oval shaped white wings perhaps 3 or 4mm long. There was also some stringy fuzzy fungus.

Guano pile number 3 had some of the gnats with white wings but not much else. The last two bait sticks are on guano pile number three. I examined them and found numerous insects. I took several pictures of them for future identification. They also have several kinds of mold or fungus on them. The mold was various colors black, white and army green.

Guano pile number 6 had almost no guano on the gauge, but there was a ring of fungus about 14 inches wide and six feet across all the way around. It was about 12 inches in from the edge of the pile.

After checking out all the guano piles, we took a short snack break at the Lunch Room. We left the Lunch Room at about 1:30pm to start the bat census. As we moved downstream Craig and Jim did most of the counting. Andy and I kept notes on the numbers.

We saw several small clusters of bats between the 4000 foot and 3500 foot markers. We did not count individuals. At a guess there were from 20 to several hundred individual bats in each of about 20 clusters. Slightly downstream from the 4500 foot marker we found a guano pile about 3 feet across with numerous small brown beetles on it.

It was about 4:30 when we arrived at the Mountain Room. We found a suitable place and fixed a hot meal. After that we explored around some. Andy found a small cluster of bats in one corner. Jim and Craig explored an overlook that goes up one side of a dome. There are several small leads coming off this area that need to be explored. On a guano pile we found a millipede measured at 43mm long which I took a picture of.

We placed four new guano gauges in the Mountain Room. They are numbered 30 though 33. Andy, Craig and Jim climbed up on top of a huge rock and I tried to get a picture of them. The pictures are dim but usable.

We left the Mountain Room about 6:10 to head back. The first 3000 feet or so is fairly easy and went quickly. After that we struggled in the mud all the way to the Lunch Room.

We finally arrived back at the ladder shortly after 9:00am. There was only four sets of vertical gear, so we assumed Spike and his team were already out. After gearing up we all climbed the ladder together. We were out of the cave by 9:30. Everything was derigged and the cave locked up by shortly after 10:00pm.

The next morning I checked out the data on the shuttle. It showed that the download from the rain gauge had not worked. I drove back up the hill to download the rain gauge.

Summary of data collected:

2 millipedes, one at 25mm and one at 43mm

Isopod sizes:
2mm = 2
3mm = 18
4mm = 25
5mm = 12
6mm = 8
7mm = 7
8mm = 5
10mm = 2

Around the guano piles and upstream of the Lunch Room: 50 bats, 5 salamanders, 1 cave fish

Guano guage 1 = no activity.
Guano guage 2 = about 30% covered.
Guano guage 3 = about 25% covered.
Guano gauge 4b = 10 turds, less than 10% covered.
Guano gauge 4A = completely covered, depth about 1cm
Guano gauge 5 = 2 turds, otherwise clean
Guano guage 6 = clean
Guano gauge 7 = one turd, otherwise clean
Guano gauge 8 = one little spot on edge, otherwise clean
Guano gauge 11 = 4 turds, otherwise clean

(note, these two should probably be numbers 12a and 12b)
Guano gauge 15a = completely covered, depth about 1cm
Guano gauge 15b = about 70% covered.

Guano gauge 13 = about 50% covered
Guano gauge 14a = completely covered, depth 0.5 to 1 cm
Guano gauge 14b = completely covered, about 0.7cm depth, several kinds of fungus
Guano gauge 15a = completely covered, 2 to 2.5 cm depth
Guano gauge 15b = Completely covered, 2 to 2.5 cm depth
Guano gauge 16 = completely clean

Lunchroom to 6000 foot = 16 bats
6000 to Paradise Passage entrance = 39 bats, 3 salamanders
Paradise Passage entrance to 5000 = 20 bats, 1 salamander
5000 to 4500 foot = 42 bats, 1 salamander
4500 to 4000 foot = 25 bats, 1 frog
4000 to 3500 foot = 20 clusters, 20 to 100 individuals each, about 100 individual bats not in clusters
3500 to 3000 foot = 42 bats
3000 to 2500 foot = 47 bats
2500 to 2000 foot = 91 bats, 1 salamander
2000 to 1500 foot = 71 bats, 2 clusters ~45 and ~100, lots of guano in stream.
1500 to 1000 foot = 37 bats, 5 salamanders
1000 to 500 foot = 67 bats, 2 clusters ~300 and ~60

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