Californian Weekend: Joshua Tree and Environs

Joshua Tree National Park

I spent the Easter long weekend in California and spent a couple of nights at Joshua Tree Natinal Park and Anzo Borrego State Park in the south east of the state. My main targets were rodents: kangaroo rats in particular.

A three hour night drive through Joshua Tree was unproductive. Maybe the full moon, or maybe the temperature – still down in the mid 50s – was to blame as Fiona Reid and Vladimir Dinets were bombarded with kangaroo rats when they were there last October. I only saw one rodent cross the road: an unidentifiable kangaroo rat. A Bobcat did dash across the road at about 10 p.m. though, not far from the Cottonwood Campground and I saw plenty of Black-tailed Jackrabbits and Desert Cottontails. I camped on Bureau of Land Management land, just south of the park. The habitat didn’t look great but the next morning I had three different rodents in my traps.

A Pocket Mouse species that refused to leave the trap when I wanted it to, which then escaped.

Desert Kangaroo Rat, Dipodomys deserti

A gorgeously fluffy Desert Kangaroo Rat, my main target for the night before. This species is supposed to weight 70 – 140 grams but this was a small one, only 40g. I imagine it must have been a youngster.

Desert Kangaroo Rat, Dipodomys deserti

And a Desert Woodrat, a second lifer for me, which was extremely placid in the hand.

Desert Woodrat, Neotoma lepida

I spent Saturday exploring bridges in the Cibola National Wildlife Refuge. California Leafnosed Bats Macrotus waterhousi used to roost under at least one bridge in this area and I checked it out. No longer… though the east end of the bridge across the Colorado River, on Hart Mine Road, appeared to have an active night roost of a species, possibly Macrotus. I did see some Mexican Freetailed Bats in the cracks of the bridge a few miles to the north, just above where the Colorado River no longer forms the Arizona/California border (i.e Arizona is on both sides of the river).

Mexican Freetailed Bat, Tadarida brasiliensis

The next night I stayed at Borrego Springs, where I was looking for Dulzura Kangaroo Rats in Anzo Borrego State Park. Vladimir Dinets told me that they were common in the campsite and I saw three or  four kangaroo rats in the evening and another four just before dawn the next morning. I satisfied myself that at least one of these was a Dulzura Kangaroo Rat. The rest I am not sure about… I only got a brief glimpse of each animal and they might have been Merriam’s Kangaroo Rats. I usually have considerable difficulty getting a prolonged look at any kangaroo rat: they generally bolt as soon as I shine a light on them.  Does anyone have a better technique for observing this species? But Vladimir has seen only Dulzura Kangaroo Rats in the campground, which is reassuring, although Curtis Hart sent me a photograph of a Merriam’s he saw there. Which is not reassuring!

Other mammals there included a Kit Fox at dusk, and more Black-tailed Jackrabbits and Desert Cottontails.

Jon

Anzo Borrego State Park