Abstract: The extent to which it is possible to accurately monitor animal populations depends greatly on how that animal's behavior affects its observability. Yet behaviors that determine observability are often affected by demographic and environmental factors. The purpose of my study was to determine the effects of population density on surface level activity and territorial behavior of the red-backed salamander, Plethodon cinereus. To accomplish this, I established 10 replicates of both high and low density P. cinereus populations within enclosures at Mountain Lake Biological Station. Over a period of 4 weeks I determined the average # of times individuals in each treatment were observed occupying cover boards, the average # of movements between cover boards per individual per treatment, the average # of times individuals were observed on the surface at night per treatment, and the mean distance traveled by individuals per treatment. I found that a higher proportion of P. cinereus in low-density treatments were observed on the surface during both daytime cover board searches and nighttime observations. The mean distances moved by individuals in both treatments were similar, but individuals in high density treatments showed significantly more variance in their movements. These findings may have implications regarding the effectiveness and validity of current P. cinereus monitoring techniques.