In the middle of what is generally a slow time, biological-survey-speaking, I got the opportunity to join the San Diego Natural History Museum’s (SDNHM’s) mammal group for a survey near Banning on December 16-17, 2013, as part of the Grinnell Resurvey Project (http://mvz.berkeley.edu/Grinnell/). Concerned that I would regret taking two days off just before leaving town for Christmas, having a report due on the 17th, I nevertheless packed up the camping gear and headed out to Banning.
Canyon bat (a.k.a western pipistrelle; Parastrellus hesperus) from Banning, CA
What an experience! After setting out and baiting the Sherman and Tomahawk traps and digging in the “cup traps” (literally plastic drinking cups, dug into the ground flush with the ground surface and acting as small pitfall traps) on the first day, Drew Stokes (SDNHM bat expert extraordinaire) and I returned to camp to set up for bat mist netting across the pool at our KOA campground home for the week. Shortly after sunset, out came the bats, and it wasn’t long before we had a tiny canyon bat (=western pipistrelle; Parastrellus hesperus) in our mist net! Crikey, what a beauty! With her two-toned coloration and fierce expression, she looked like a tiny, winged honey-badger. After a series of measurements on this little lady, we placed her into a cloth bag and then into my sweatshirt pocket to warm up prior to release. I was grateful the bag did not have a loose weave, as at $940 (not covered by insurance), I have not yet invested in rabies shots.
The next morning we rolled out of our tents and into vehicles to check the mammal and cup traps. On the way to the site we watched a prairie falcon attempt to breakfast on some European starlings, with no luck. Upon inspection, we found that we had caught a variety of rats and mice in our Sherman and Tomahawk traps including agile kangaroo rats (=Dulzura kangaroo rats; Dipodomys agilis simulans), deer mice (Peromyscus maniculatus), cactus mice (Peromyscus eremicus), and California mice (Peromyscus californicus). Apparently this was a slow day according to the mammal team, with small numbers of animals at most of the trap arrays, but for me this day was anything but slow. Without trapping, the most I (a biologist generally doing my surveys in the daylight and being a relatively large, lumbering mammalian creature) will see is an isolated, split-second glimpse of a small rodent skittering away into the brush, so for me this was quite an experience. Interestingly, the Dulzura kangaroo rats are very docile, politely tolerating handling by biologists.
Dulzura kangaroo rat
A Dulzura kangaroo rat in the hand (is worth two in the bush?). Am I enjoying this little guy? You be the judge.
Dulzura kangaroo rat close-up. Look at the size of that head! It’s like an orange on a toothpick!
Dulzura kangaroo rat close-up
Our cup-traps even yielded a western skink, another species I would rarely observe as a lumbering, diurnal field biologist.
Western skink (Plestiodon skiltonianus)
Western skink (Plestiodon skiltonianus). Note striping on side of tail extending beyond hind legs (versus Gilbert’s skink).
We returned to camp to process specimens and, in my case, finalize and submit a report. I am very grateful for the ability to use my phone to create a mobile hotspot, which allowed me to incorporate client comments and submit my report from the comfort of my campsite. After an improvised lunch of canned tuna, oranges, and trail mix, Drew and I set off to an abandoned mine to check for roosting bats, particularly Townsend’s big-eared bat (Corynorhinus townsendii; recently proposed for listing as a California threatened or endangered species), which had been collected from this mine in the past. We also set up and disguised a bat detector, which will record and store bat calls for later analysis. Although we did not observe any bats roosting inside the mine, Drew later confirmed Townsend’s big-eared bat by analysis of the calls recorded by the bat detector.
After re-opening/setting the small mammal traps again and baiting with oatmeal, we returned to the KOA pool once more to mist net. As with the previous night, I was able to hear the calls of the pocketed free-tail bats (Nyctinomops femorosaccus) foraging in the area, but as a male unable to hear such high frequency sounds, Drew was not. We did not catch any pocketed free-tail bats in the mist net as they typically fly higher than our net was set, but we did catch another western pipistrelle, or ahem, canyon bat. Once set free, although this bat likely could not detect the mist net visually or via echolocation, it obviously retained a very good spatial memory of the net’s location, as it dove and sallied expertly around the net.
Sadly I only had two days to spend with this amazing team of highly knowledgeable scientists, but am hoping to join up with them again any time they will have me. Thank you San Diego Natural History Museum Mammal Team for graciously letting me tag along and filling my head with knowledge. Thank you also to Debbie Schaffer at SDG&E for hooking me up with these great scientists!