Miller and Ralph 



Chapter 20 



Inland Habitat Relationships in California 



Table 7 Marbled Murrelet use afforest stands in northern California. 

 .\umbers represent individual stands for isolated stands surveyed surveyed 

 four times during the Stand Study or stations for surveys conducted in each 

 12.5 ha of a large contiguous stand for the Park Study or in preparation for 

 timber harvest 



1 All stations or stands with murrelet detections, including occupied behaviors 



found in Oregon (Grenier and Nelson, this volume) and 

 Washington (Hamer, this volume). 



We found the presence of redwood as the dominant tree 

 species to be a factor for predicting higher mean detection 

 levels and stand occupancy. In Washington, Hamer and 

 others (1993) also found tree species composition to be an 

 important factor for murrelet occupancy. Within the range of 

 our study, stands dominated by Douglas-fir often were in 

 drier areas with higher summer temperatures. Sites very 

 close to the coast are usually dominated by Douglas-fir and 

 Sitka spruce (Picea sitchensis) and, for unknown reasons, 

 also lack murrelets. 



Contrary to previous studies we did not find larger 

 stands more likely to have murrelets present or to be occupied. 

 Other factors, such as, stand history and juxtaposition to 

 other old-growth stands may mask the effects, if any, of 

 stand size on murrelet presence and use. 



Although in the Stand Study we did not find a significant 

 relationship between distance from the ocean and murrelet 

 detections or behaviors, this possibly was related to the limited 

 range of distances for stands surveyed. Our examination of 

 all surveys from 1988 through 1992, however, indicates a 

 strong pattern of declining murrelet presence with distance 

 from the coast (table 7). The number of stations more than 40 

 km inland with murrelet detections was only about 2 percent. 

 One factor which may have biased the bands >40 km inland 

 was the selection of the survey sites. Many of these sites 

 were located in forest habitat selected for timber planning 

 and not considered optimal for murrelets. A lack of murrelet 

 detections would then allow timber harvesting on some of 

 these lands. Further studies inland in California at sites selected 

 by unbiased methods would provide needed information on 

 the murrelet' s distribution in these areas. 



It is unlikely that one factor alone will best describe 

 murrelet habitat. Density of old-growth cover and species 

 composition are included as important factors in more than 



one analysis. These variables may be the strongest predictors 

 of murrelet presence in California. 



Large Contiguous Stands 



Within the large stands of old-growth in the parks, most 

 stations with observations of occupied behaviors occurred in 

 the major drainages and, correspondingly, at low elevations. 

 Occupied behaviors were observed at 69 (73 percent) of the 95 

 stations in the major drainages. Trees in these drainages tend 

 to be larger, and experience less limb breakage from wind 

 (Tangen, pers. comm.). Both of these factors could contribute 

 to larger diameter branches and more potential nest platforms. 



Acknowledgments 



This research was a cooperative effort with private 

 landowners in California who formed the Marbled Murrelet 

 Study Trust including: The Pacific Lumber Company, Arcata 

 Redwood Company, Miller-Rellim Company, Big Creek 

 Lumber Company, Simpson Timber Company, Sierra-Pacific 

 Industries, Barnum Timber Company, Eel River Sawmills, 

 Louisiana-Pacific Corporation and Schmidbauer Lumber 

 Company. We especially would like to thank Lloyd Tangen 

 and Lee Folliard who gave frequent help and encouragement. 

 Jim Brown, Sal Chinnici, Joe Dorman, Steve Kems, Ray 

 Miller, and Rob Rutland also gave of their assistance and 

 insight. We appreciate the guidance of members of the 

 project's advisory committee, which included members from 

 all cooperators and agencies, and the U.S. Fish and Wildlife 

 Service, especially Mike Horton. Financial support for the 

 study was provided by the Marbled Murrelet Study Trust of 

 the timber companies, USDA Forest Service, California 

 Department of Fish and Game, California Department of 

 Forestry, California Department of Parks and Recreation, 

 and Redwood National Park. We thank Jennifer Weeks, 

 Brian O'Donnell, Deborah Kirstan, and Ann Buell for their 

 assistance with data preparation, analysis and manuscript 

 reviews and James Baldwin for his statistical advice. We 

 appreciate also the reviews provided Martin Raphael, Alan 

 Burger, Frank Thompson, Mark Huff, Marty Berbach, Valerie 

 Elliot, Sal Chinnici, Lee Folliard, Todd Sloat, and Steve 

 Kerns. We appreciate the efforts of the many field personnel 

 who gathered data for the study. 



Appendix A 



Designing a study to examine the relationship of Marbled 

 Murrelets with forest habitats requires first determining if 

 the birds are present or absent from individual forest stands. 

 Here, we outline the methods used to determine the appropriate 

 number of surveys required when the objective is to determine 

 murrelet presence or absence. 



For our study, we wished to know how many survey 

 mornings were necessary to determine presence in a stand of 

 murrelets with a 95 percent probability of being correct. We, 

 therefore, set the level of probability of a false negative at 5 



USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. 



213 



