The species diversity, species richness, and mean number of individuals by site per visit are presented in Table 1. Species diversity measures ecological diversity based on the number of species detected within 50 meters weighted by the number of individuals of each species. Species richness is defined as the number of different species detected within 50 meters over the entire transect. The mean number of individuals per station per visit represents an average of how many birds were detected at any one site along the transect in a single visit. Through such monitoring we can begin to understand the health of our riparian songbird populations and habitats.
Diversity is a good measure of the ecological health of an area.
Three visits to each site is the standard protocol for point counts and provides a more accurate index for each site than does one visit. However, to be able to compare the sites that were only visited once to the rest of the sites, I chose the visit for each site closest in date to the single visit to Aptos and Chalone Creek for analyses. Species diversity, richness, total individuals, and mean number of individuals per station per visit and presented for one visit to each site in Table 2 . You may notice that all sites that were also analyzed for all three visits had lower diversity and richness indices when only one visit was examined. T ABLE 1.