2017-06-17~20 Cottonwood Springs

Little Pocket Mouse - Perognathus longimembris bangsi From June 12th to the 20th, the San Diego Natural History Museum science team focused their mission on Cottonwood Springs and the Pinto Basin at the southeastern corner of Joshua Tree National Park. I had my 50th High School reunion to attend, but joined the group on the 15th and stayed to the end. The purpose of the expedition was to resume the restudy of the biological surveys started by Joseph Grinnell’s teams from Berkley’s Museum of Vertebrate Zoology in the early twentieth century.

It was hot to the extreme and registered into the one hundred teens (°F) most days. Had the Park Service provided us with a house to work from, I don’t think it would have been wise to undertake the expedition. Seventy years ago, when teams from Berkley were studying the fauna here, they had to do it from tents and primitive camps. Those hearty folks in the 1920s, ‘30s, and ‘40s probably had to suffer for the science. I don’t know how they dealt with the threat of heat exhaustion.

This outing was the debut and initial test for the new Rat Theater tent. I believed the modifications I applied to the tent for limiting entry of outside light sources would achieve the desired results, and they did. As a freestanding structure it relieved me from having the van nailed to the ground, preventing me from moving the RV, as the Add-A-Room did. On this excursion I managed to transport myself and run errands without disturbing the theater setup. The next museum excursion I’ll need it for, will be next fall. There are just a couple of improvements I plan to apply before then.

One interesting observation by both the mammalogists and the ornithologists on this trip, was the animal subjects found here were juveniles. All the Phainopeplas, Northern Mockingbirds, and many of the House Finches I saw were juvenile birds. As a rule, mammalogists don’t collect juveniles for museum specimens. When caught, we document, then release them. On the second to the last day, the team delivered a juvenile Desert Pocket Mouse to the Rat Theater for photographs by mistake. In the dark of the early morning it must have looked like a Little Pocket Mouse, but when I got it under the lights in the Rat Theater, it lacked the tan tones in its pelage I expected to see. In the full light of day, Scott gave it a closer inspection and confirmed my suspicions. As either a juvenile Pocket Mouse or a Little Pocket Mouse, it was bound for release, anyway.

The Little Pocket Mouse is a species of special concern, and people have petitioned for its “endangered” status. Broad areas of the desert, especially in the Coachella Valley, developers converted to agricultural, residential, and commercial uses. This conversion rendered the habitat there unusable for this small mouse. There are nine subspecies of the Little Pocket Mouse, all of which are struggling to maintain a foothold in the ecosystem.

I’ll post the bird images later, but below are the subjects captured in Rat Theater: