Behavioral Ecology Blog

OK, so it is true that nobody ever said field work was easy- but why can’t these mice just cooperate? I’ve been so nice to them (except that part about cutting off their ear and sticking something in their vagina’s), it seems as if they would have grown to love me by now…

Well seriously, I’m trapping in an area that last year was literally overflowing with mice.. Now, after 3 night trapping, I have caught a grand total of 3 individual Peromycsus eremicus (all of which I marked last year), and 4 Cheatodious formosus.. Easily I should have 5X this number… There are a couple of possible reasons, I have my suspicions which is the right one- but I don’t really know.

1. Southern California is in the midst of one of it’s worst droughts ever.. Although the mice don’t need drinking water- they do need to eat plants (seeds) that need water to flower and produce seeds. Perhaps the severe lack of rainfall has caused the population to “crash”
2. It has been unseasonable cold the past week- maybe so cold that they are simply staying home. This explanation is doubtful- I another researcher comes to Deep Canyon every year in March (when the temperature is even colder) and he catches plenty of animals.

I guess I wasn’t expecting the animals to be breeding- as it is known that this does not occur in drought years- but such a crash I did not expect.

Tonight, I am trapping near one of the oases that is on the reserve. This is a really neat area- as it has perennial spring water. Even in the dead of summer- water flows. As such, animals flock there in times of water stress. Even now, in drought, there are plenty of green things and flowers, etc. If drought is the reason that the mice are not coming out to play- tomorrow my traps should be full of eager participants…I’ll keep you posted on that….

PS- Pic is of one of the non-mammal occupants of the oasis- Pseudacris cadaverina