Since 2000 Leslie Canyon NWR has been conducting a long term population dynamics study on reptiles and amphibians on the refuge.  Along with reptiles and amphibians, information is gathered from the incidental captures of other organisms.  2007 saw a dramatic increase in the number of incidental mammal captures, 434, as compared to previous years as well as an increase in the number of different species captured.  This is believed to be due to natural cycles and a wet winter in the area. Individuals captured in the traps are identified, aged, sexed, measured, weighed, and PIT-tagged or otherwise marked to allow identification of individuals or recaptures.  Date, precipitation, trap array location, and trap type are also recorded for each individual, along with disposition and other comments.  This year the traps were operated from April 2^nd through October 31^st for a total of 6816 trap days and were checked everyday during the months of July and August and every other day for the remainder of the season.  Total captures for the year were 842 individuals comprising 36 different species.  The previous high mark for captures was in 2003 with 324 total captures.  In addition to the overall large number of individual captures, we also had some new species that have never been caught in this study.  Some of these species were Sonoran desert toad (Bufo alvarius), coral snake (Micruroides euryxanthus), Northern grass hopper mouse (Onychomys leucogaster), Hispid cotton rat (Sigmodon hispidis), and tawny-bellied cotton rat (Sigmodon fulviventer)