Breeding bird censuses were conducted at Olema Marsh in from 1984-1994. These censuses used spot mapping to quantify the number of occupied territories indicated by the presence of territorial (singing) males (I.B.B.C. 1970, Ralph et al. 1993). Spot-mapping is best used to quantify the number of the breeding songbird pairs, but it is less effective for monitoring the use of an area by polygynous marsh birds (e. G., Marsh Wren, Redwinged Blackbird), non-territorial breeders (e. G., American Goldfinch, Mourning Dove), and nesting waterfowl (e. G., Ruddy Duck, American Coot, Gadwall). Breeding-bird use of Olema Marsh was last evaluated in 1993 and a survey of bird use in autumn has not been conducted since 1984. To generate more current information on bird use in Olema Marsh and to more effectively measure the densities and occurrence of breeding marsh birds, we conducted a series of point counts in the spring and fall of 2004. Point counts of wintering birds are being conducted during January of 2005. Although we included detection distances in all counts to allow for the estimation of detection probabilities and breeding bird densities, this report presents only the uncorrected point-count totals as indices of species abundances.
Stallcup, R. W., and J. P. Kelly. 2005. Point-count surveys of bird use in Olema Marsh: Spring and Autumn 2004. A report to the Point Reyes National Seashore. ACR Tech. Rpt. 2004-2-1. Audubon Canyon Ranch, P.O. Box 808, Marshall, CA 94940.