Chapter 19: Marbled Murrelet Habitat Associations in Oregon

Abstract

We described habitat associations of Marbled Murrelet (Brachyramphus marmoratus) nesting (n = 10) and occupied (n = 184) sites in Oregon. We compared habitat characteristics of 177 occupied sites to a random sample of 9,625 sites (n = 531) of unknown murrelet status. In addition, we briefly described the characteristics of 22 nests and compared 10 of the nest sites to adjacent sites. In general, occupied sites were older, had larger midstory trees, and had larger and greater densities of dominant (or remnant) trees than random sites. In addition, dominant tree height and density, midstory and understory tree diameter and percent cover, and percent canopy closure were important habitat components for predicting murrelet occupancy. All nests were in old-growth Douglas-fir (Pseudotsuga menziesii), western hemlock (Tsuga heterophylla), and Sitka spruce (Picea sitchensis) trees > 127 cm in diameter and > 36 m tall. Murrelet nest sites had fewer trees/ha and less canopy closure compared to adjacent sites. Our results support previous studies that concluded murrelets use stands with old-growth characteristics and that stand structure is more important than stand age. Knowledge of habitat associations does not imply habitat quality, which should be quantified through studies on reproductive success in relation to habitat and landscape characteristics.

Parent Publication

• Ecology and conservation of the Marbled Murrelet

Citation

Grenier, Jeffrey J.; Nelson, S. Kim. 1995. Chapter 19: Marbled Murrelet Habitat Associations in Oregon. In: Ralph, C. John; Hunt, George L., Jr.; Raphael, Martin G.; Piatt, John F., Technical Editors. 1995. Ecology and conservation of the Marbled Murrelet. Gen. Tech. Rep. PSW-GTR-152. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture; p. 191-204