Sorry I have not posted in awhile. I have put my "basic" nonlinear model into matlab and it is up and running. I have been trying to find birth rate terms in terms of copulation attempts per couple* pregnancy success rate. This birth rate needs to incorporate both males and females since my nonlinear model depends on both sexes (and it is the only way my units cancels out). I found a couple papers that may help with this kind of data. I also found some interesting information about maturation rates; mice in warmer climate mature faster than mice in colder climates, while the difference is only about a weeks time, it could impact my data, so I plan to play around with this in my matlab model. I am now going to work on developing a carrying capacity (I need to decide what I want it to depend upon i.e nutrients, rainfall, etc.) A critical depending factor for this would include the diet of white footed mice; I found that the main sources of food throughout the year are insects, but additionally in the spring and summer they eat fruit and in the winter and fall they eat seeds/green vegetation.