Nelson and Hamer 



Chapter 5 



Nesting Biology and Behavior 



Table 5 Mean number of feeding visits observed per day' at Marbled Murrelet nests by state and province 2 



1 Not all nests were monitored during mid-day or at night, thus some feeding visits may have been missed. Data 

 include only days where nests were monitored at dawn and dusk on all observation days. 



2 Data from Hamer and Cummins 1991 ; P. Jones, pers. comm.; Kerns, pers. comm.; Nelson and Peck, in press; S.W. 

 Singer, pers. comm. 



3 No tree nests with chicks were observed in Alaska; data from 2 ground nests in Alaska were not available. 



4 Two nests in Oregon and 1 in California were not monitored at dawn and dusk on the same day. 



0500 0700 0900 1100 1300 1600 1800 2000 



TIME 



Figure 1 Number of feedings by time of day (0500-21 00 hrs) at ten Marbled 

 Murrelet nests in British Columbia, Washington, Oregon, and California (n = 

 206 feedings). 



feedings occur from 90 minutes before, to 7 1 minutes after, 

 official sunset, with the last feeding visit occurring 40 minutes 

 before, to 71 minutes after, official sunset (x = 18.4, s.e. = 

 4.1, n = 41 feedings at 12 nests) (Hamer and Cummins 

 1991; Naslund 1993a; Nelson and Peck, in press; Singer 

 and others, in press) (table 7). No nocturnal (after dusk) 

 feeding visits were recorded during all-night observations 

 in Washington and California (n = 38 nights at 3 nests) 

 (Hamer and Cummins 1991; Naslund 1993a). 



On several occasions (n = 1 of 68 visits at three nests), 

 two adults arrived at the nest with fish at the same time 

 (Kerns, pers. comm; P. Jones, pers. comm.; Nelson and Peck, 

 in press). In Oregon, when this occurred, one adult flew 



away, and returned only after the other adult had left. In 

 California and British Columbia, both adults left and returned 

 individually at a later time, or both remained until the chick 

 had eaten one of the fish. 



Adults usually carry single fish in their bills, holding it 

 crosswise at the mid-point of the fish's body, or just posterior 

 to the operculum. On several occasions, adults were observed 

 arriving with 2 fish at nests in California and Oregon (n = 

 3)(Buchholz, pers. comm.; Kerns, pers. comm). When adults 

 arrive at the nest with a fish, they often remain in a motionless 

 posture on the landing pad for up to 11 minutes before 

 approaching the nest (n = 11 nests) (Hamer and Cummins 

 1991; Kerns, pers. comm.; Naslund 1993a, pers. comm.; Nelson 



62 



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



