San Diego RFI

I’m in San Diego for a conference, and it looks like I’ll have Sunday afternoon – Monday morning free to look for mammals. Does anyone have a recommendation for where to go for one night? I’m thinking Anza-Borrego or Joshua Tree, but haven’t seen any reports for this time of year.





  • Venkat Sankar

    IMO, the main attractions in that part of CA are heteromyids and bats, of which heteromyids would be difficult and bats mostly impossible to find this time of year. That said, the weather in the area looks reasonable (temps 55-60) with no bright moon, so it maybe worth a try. Check out my and Jon’s reports from last Spring for location details.

    There are many interesting pocket mice (Baja, Spiny, San Diego) in Anza-Borrego and the southern part of Joshua Tree. In Anza-Borrego, find very quiet dirt roads covering many different habitat types (e.g. boulder-filled canyons, moister high desert, sandy low desert, gravelly alluvial fans, etc.). Niche partitioning is very strong among these species, so if you search the right habitats, you’ll have a decent chance of finding and identifying species. If you see a pocket mouse, you usually need to jump out of the car and try to get a decent view of the diagnostic features as it scurries away. Night walking in such places may also be good.

    Try Little Blair Valley for Baja and San Diego Pocket Mice (Merriam’s Kangaroo Rats also abundant here), any boulder-filled canyon for Spiny Pocket Mouse, Arroyo Salado area for Long-tailed and Baja Pocket Mice, and dirt roads in the valley near Borrego Springs for Desert Pocket Mouse (this site also has abundant Merriam’s Kangaroo Rat, Kit Fox, and a strange small form of Desert Kangaroo Rat). Even at good times of the year, the pocket mice aren’t easy to find and you’ll confidently see and ID only 2-3 sp. even with several hours of effort. Bighorn Sheep may be easier to find now (less tourists in the valley) and I’ve been told late night drives on Montezuma Grade are good for Ringtail. I have to admit that I love this park most for its plants and reptiles, neither of which will be at their best this time of year…

    Another recommendation would be to try Crown Valley and Thomas Rd, near Hemet. Temperatures will be more moderate, as its closer to the coast, and you shouldn’t need 4WD (I’d recommend it for exploring in the desert). The key species are Stephens’ (endemic) and Dulzura Kangaroo Rats, San Diego Pocket Mouse, and Northern Baja Mouse, all of which should be findable now. That said, someone visited recently and reported they didn’t see any, so I’m not sure.

  • Louis Freeland-Haynes

    Hi Ben, I’m also in San Diego for (I imagine!) the same conference. I’m travelling down Baja california straight afterwards to see the gray whales and any other birds/mammals I can connect with, but may have one evening free in San Diego on the way back. Please do post with how you get on as I may try and do the same!

    • geomalia

      Hi Louis, I spent a day and a night at Anza Borrego, which was excellent. I saw many kangaroo rats and a few pocket mice; the Hellhole Palms trail was particularly good for them. I also observed a Desert Kit Fox along the road to the Slot Canyon trail, and a herd of Bighorn Sheep from the Montezuma Grade. Another herd of sheep was being seen daily from the Borrego Palm Canyon trail, but I skipped it because of the crowds.


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