O'Donnell and others 



Chapter 1 1 



Patterns of Seasonal Variation of Activity 





BCCO HHRD JCAM OCPA 

 STUDY SITE 



RLMF 



Figure 12 Mean number (histogram bar) and standard error (line segment) of Marbled Murrelet 

 detections by season at five study sites in central California. "Summer" includes April-July and 

 "winter" includes November-February. Sample sizes (number of surveys) are indicated in histo- 

 gram bars. From Naslund 1 993b. 



100 



SBP OCT NOV DBC JAN PBB MAR APR MAT JUN JUL AUO 



MONTH 



Figure 13 Percent of surveys with detections of Marbled Murrelets by month for five study sites 

 in central California, 1989-1991. Surveys from all sites were pooled. Sample sizes (number of 

 surveys) are indicated in the histogram bars. Missing histogram bar in September denotes that no 

 murrelets were detected during 14 surveys. From Naslund 1993b. 



126 



USD\ Forest Service Gen. Tech. Rep. PSW-152. 1995. 



