Last Sunday (2016-09-24) I left Poway for Cottonwood Spring in southern Joshua Tree National Park to stay with members of the museum’s science team for the week. With the San Diego County Mammal Atlas coming near the end of preparation, there were a couple of species we’d hoped to get images of, and we thought we could piggy-back it onto the restudy project that the museum has recently undertaken.
The team comprised myself (for photography), Scott Tremor (science team leader), Lea Squires (biologist), and for one day, Lori Hargrove (biologist, coordinator).
The general rhythm of the expedition began with a late afternoon session of Scott and Lea setting traps to catch small rodents. Traps (called “Sherman Traps”) the team uses are amazing little collapsible aluminum boxes that pop open to a 3” x 3.5” x 12” with a spring-loaded trapdoor on one end. An animal enters the box to find the few pieces of rolled oats inside. As it reaches the full depth of the box, it steps on the trigger and the trapdoor snaps shut. Each evening, people set hundreds of traps, and about 20% of these traps successfully capture animals. At dawn the next morning all the traps would get collected. Team members document, mark, and release most of the specimens. They brought a selected few back to camp for me to photograph.
While the team was out managing the traps, I would setup the ‘theater’ for the photographs. The theater stage was a glass aquarium that I broke the bottom from. By placing the enclosure on the native ground, the natural substrate presented for the subject captures to roam on. I learned to place objects inside the theater (rocks, sticks, cactus pieces, etc.) for the subjects to pose near. Placing brush and rocks behind the aquarium (terrarium) helped to complete the illusion. Rearranging the scene from time-to-time helped to give variety to the images I would capture. A screened lid with a hole cut out of the middle to introduce the subject to the stage, and some lighting to sit overhead and I was ready to take pictures.
I spent afternoons and evenings sorting and grooming images while Scott and Lea prepared the specimens I’d photographed in the morning for the museum’s collections. While preparing the animal skins had an element of gruesomeness to it, there was an important scientific contribution to be appreciated. The way the team worked through the evening, and the good natured conversations that accompanied the process, reminded me of a friendly card game, or sewing circle with busy hands and witty conversation.
There were many useful images that I collected on this expedition. Today I’m sharing one of the surprise subjects that were discovered here; The Northwestern Baja Pocket Mouse. This mouse was once called the Bailey’s Pocket Mouse, but that species was recently split. We’ve not been able to locate images of the Northwestern Baja Pocket Mouse for the San Diego County Mammal Atlas, so getting quality images was quite a pleasant surprise. We believe, that this discovery documents the northern extent of this animal’s range. It goes to show trapping is like a box of chocolates; you never know what you’re going to get (sorry Forrest).
