Behavioral Ecology Blog

So another week (or 2) has passed… I have been to several locations- some pretty cool. I am however, sad to report to that the mice continue to be illusive. Every place I go, there are mice, but not very many. The probability that I fond a population of breeding mice decreases with time..

Last week, I returned to Echo Valley, and stayed at Lake Cuyamaca State Park. There, I waded through large stands of Poison Oak (see photo)- and definitively proved that I am not suceptable to it’s poison.. Yah!!! In addition to a few P. eremicus, I caught a P. maniculatus and a Chaetodipus californicus- a new species for me. They are medium sized pocket mice with spines on their rump- but large ears, which is uncommon for semi-fossorial animals like the pocket mice.. Cool.

From there, I was plannin on going to the San Felipe Valley, where 18 months ago, I had to wade throught the mice.. They were SO plentiful.., San Felipe Valley is a spring fed valley that is usually wet and lush- this year- dry as a bone.. I didn’t even bother spending the might…

Since SFV didn’t pan out, I decided to go to Witch Creek, where other problems cropped up…. Now you remember hom I’m choosing places to go? I am using the MVZ database and Google Earth (amazong by the way) to identify places where multiple species of mice are located. This is great, and has led me to several really nice places, and had taught me the importance of elevation.. So anyway, I use my map, find a spot, and go there. Now I think this is going to be a great place, and BOOM, the place I need to be is behing locked gate and barbed wire.. This was been the case at several locations, including Julian and Witch Creek. Bummer…

Anyway, as a result, I decided to hear northwest to a place near Palomar- about 5000 feet high and supposidly teeming with animals.. Well, can’t vouch for the animals part- but is was an amazing place, full of wildlife. I’d like to take the family there sometime!

From there, to Santa Ana Mountains, near the border between Orange and Riverside County. I stayed in a place called Upper San Juan, where the mice were BOOMING. With 60 traps, I caught 12 animals, but sadly no P. eremicus. I did get another new species for me- P. truei, which is recognizable by the HUGE dumbo like ears.. You see???

This week I’m spending 2 mights in Deep Canyon, simply monitoring this population of P. eremicus. What OI can tell you after last night, is that the population is in serious trouble… I hope it rebounds next year, but I’m not too sure.

I layed 60 traps in primo eremicus habitat, and got 1 eremicus, and 5 Spiny Pocket mice. Trapping in the same area last year would have easily got me 5-10 mice.. I’ll trap one more night, then head back to the Santa Ana’s, a little east of Upper San Juan, in an attempt to find P. eremicus.

See the map of the areas I spoke of in this post.. I’m covering a lot of ground- with limited success. Argh…