Naslund and O'Donnell 



Chapter 12 



Daily Patterns of Activity at Inland Sites 



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MINUTES BEFORE AND AFTER SUNRISE 



Figure 1 Timing of Marbled Murrelet detections relative to sunrise in California (n = 9764; Big Basin Redwoods State 

 Park, 1 989-1 991 ; Naslund, unpubl. data), British Columbia (n = 21 42; Phantom Creek, May-August 1 990; Rodway and 

 others 1991), and Alaska (n = 1649; Naked Island, May-August 1991; Kuletz and others 1994c) 



1 hour before and 1 hour after sunrise (Walsh, pers. comm.). 

 In southcentral Alaska, murrelets were generally active 

 between 90 minutes before and 40 minutes after sunrise, 

 although the majority were detected during the 75 minutes 

 before sunrise (fig. 7; Kuletz 1991, Kuletz and others 1994c). 

 However, they sometimes were detected 120+ minutes before 

 sunrise (Kuletz 1991; Naslund, unpubl. data). In Alaska, the 

 timing of first detections varied during the breeding season. 

 Murrelets were active earliest around the beginning of summer 

 (fig. 2; Kuletz and others 1994c). 



In California, the duration of murrelet activity was longest 

 during the breeding season (fig. 3; Naslund, unpubl. data; 

 O'Donnell, unpubl. data). Conversely, their winter activity 

 period was compressed and typically ended before sunrise 

 (fig. 3). Murrelet activity occasionally began slightly earlier 

 during winter than during summer (fig. 3). Murrelets tended 

 to be active later in the morning and for shorter periods of 

 time during August than in other summer months, in both 

 California and Alaska (fig. 3; Kuletz, pers. comm.; Naslund, 

 unpubl. data; O'Donnell, unpubl. data). 



Timing and Duration of Evening Activity 



In California and Oregon, most evening detections 

 occurred from about 20-30 minutes (but up to 90 minutes) 

 before, through about 20-30 minutes after, official sunset 

 (Forma, pers. comm.; Nelson 1989; Paton and Ralph 1988). 

 Murrelets have been detected up to 45 minutes past sunset 

 in Oregon, and were rarely heard during the middle of the 

 night in California (Nelson 1989; Strachan, pers. comm.). 

 Timing of evening activity in British Columbia was slightly 



later than that observed farther south, with 95 percent of 

 detections occurring between sunset and 45 minutes after 

 sunset (Rodway and others 1993b). Elsewhere in British 

 Columbia, murrelets were most active >45 minutes after 

 sunset in early June (Eisenhawer and Reimchen 1990). 

 Virtually all evening activity in Alaska has been detected 

 after sunset, and murrelets occasionally fly inland throughout 

 the relatively bright nights around the summer solstice 

 (Kuletz, pers. comm; Naslund, unpubl. data). 



Weather Effects on Timing and Levels of Activity 



Weather has been observed to affect the timing and 

 duration of activity throughout the murrelet' s range. Murrelet 

 activity tends to begin later and last longer on cloudy or 

 foggy mornings than on clear mornings (Kuletz, pers. comm; 

 Manley and others 1992; Naslund, unpubl. data; Nelson 

 1989; Nelson and Hardin 1993a; Paton and Ralph 1988; 

 Rodway and others 1993b; Sander 1987). However, Nelson 

 (1989) noted that murrelet activity in Oregon also began 

 earlier and lasted longer on clear mornings than on mornings 

 with intermediate cloud cover, though not longer than on 

 mornings with 100 percent cloud cover. In Alaska, activity 

 several hours after sunrise was associated with heavy fog at 

 ground level or mist (Kuletz 1991; Walsh, pers. comm.). 



Environmental conditions can also affect levels of 

 murrelet activity. At nest sites in central California, total 

 numbers of detections and numbers of subcanopy behaviors 

 tended to be higher when cloud cover was >80 percent, but 

 was variable between sites (Naslund 1993a, unpubl. data). 

 Rodway and others (1993b) also found that activity levels 



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



