Burkett 



Chapter 22 



Food Habits and Prey Ecology 



Washington 



During the summers of 1968 and 1969, Cody (1973) 

 collected information on seabird breeding activity, prey 

 species, and foraging patterns off the west coast of the 

 Olympic Peninsula in Washington State. Murrelets holding 

 fish before their evening flights inland were observed at 

 close range from a boat. The birds were seen to carry only 

 anchovy (Engraulis) and sand lance (Ammodytes) in their 

 bills, and it was presumed these fish were for nestlings 

 (Carter and Sealy 1987a) (table 1). The murrelets showed 

 great similarity in chick diet with the Common Murre, 

 Tufted Puffin, and Rhinoceros Auklet (Gerorhinca 

 monocerata), though smelt (Hypomesus) and sea-bass 

 (Sebastoides) were also recovered from 54 fish loads for 

 these latter three species of alcids. 



Similar to Sealy's (1975c) study of sympatric Ancient 

 and Marbled Murrelets, Cody ( 1 973) concluded that differences 

 in foraging areas at sea reduced interspecific competition 

 between alcids off the west coast of the Olympic Peninsula, 

 though prey species consumed were similar. Lacking specific 

 knowledge of murrelet nesting areas, neither of these 

 researchers were able to compare foraging areas with nesting 

 habitat distribution, though Cody (1973) concluded that the 

 zonation of alcid feeding areas with respect to distance from 

 the nest was the most important factor affecting coexistence. 

 He contrasted this to other studies which have found differences 

 in diet between similar seabird species to be the isolating 

 mechanism. He also pointed out that foraging zonation which 

 is optimal while adults feed nest-bound young is relaxed and 

 expanded when young leave their nests and accompany the 

 parents. Cody (1973) found that murrelets fed within a few 

 kilometers of the shore. He observed that in the evenings 

 they were often seen carrying food within a half kilometer of 

 the Hoh and Quilleute Rivers and that adults and partially- 

 grown, non-flying young were observed close to these same 

 river mouths in August. 



Cody presumed these rivers provided transportation 

 for the young murrelets from inland nesting sites (Day and 

 others 1983, Nechaev 1986). The discovery of a young 

 murrelet at a freshwater marsh close to the sea in British 

 Columbia is described by Brooks (1926a). The bird appeared 

 unable to fly, and it was noted that the primaries were in 

 sheaths at their bases and there was a good deal of down on 

 the head, back, and flanks. Another similar young was with 

 it. Brooks (1926a) noted another juvenile murrelet, collected 

 off Langara Island, British Columbia: "...the bases of its 

 quills still in the sheath was taken some 200 yards out to 

 sea...". Young fledglings would consume available prey 

 resources in freshwater environments as they gained 

 sustained flight capabilities and made their way to the 

 ocean (Carter and Sealy 1986). It is thought that the majority 

 of murrelets fledge by direct flight to the ocean (Nelson and 

 Hamer, this volume a). Diving behavior is an escape response 

 and does not necessarily indicate an inability to fly (Carter 

 and Sealy 1987b); however, repeated harassment of the 

 juveniles by Cody (1973) resulted in no flight attempts, 



though adults would take wing when continually harassed 

 by boat (Cody, pers. comm.). 



Additional work by Cody in Carter (1984) at the San 

 Juan Islands again revealed anchovy as nestling prey from 

 fish held in the bill by murrelets on the water (table 1). 



One other observation on murrelet food habits from 

 Washington was provided by Hunt (pers. comm.). He observed 

 murrelets foraging in August in mixed-species flocks in the 

 San Juan Islands. He dip-netted (approximately 7.5 cm mesh) 

 for surface fish in this foraging area and captured only 

 herring (table 1). 



Oregon 



At-sea surveys for murrelets during 1992 off the coast 

 of Oregon resulted in some anecdotal information on nestling 

 food items (Strong and others 1993). A total of six murrelets 

 carrying fish were observed from 15 June to 11 August 

 (table 1). The first two observations occurred on 15 June, 

 and the prey type was judged to be "smelt sp." (osmeridae). 

 The next four observations, on 1 August, 2 August, and 1 1 

 August (two observations), were of sand lance. On the basis 

 of additional observations of other seabirds with prey over 

 the same time period, the authors thought a switch in prey 

 occurred from smelt in late July to sand lance thereafter. 



Video footage from an active nest site in 1992 documented 

 sand lance as nestling food, and during at-sea surveys, 

 observers noted osmerids, sand lance, and a possible herring 

 as nestling food items being held by murrelets (Nelson, pers. 

 comm.) (table 1). 



California 



A report on the population status and conservation 

 problems of the murrelet in California was produced in 1 988 

 as the Department of Fish and Game began gathering 

 information on the species (Carter and Erickson 1988). Field 

 notes from work by R. H. Beck in the vicinity of Point Pinos, 

 Monterey County, were included in Carter and Erickson's 

 (1988) report and are repeated here (Museum of Vertebrate 

 Zoology; see also Beck 1910): "...the Marbled Murrelets 

 yesterday [had in their stomachs] 2, 3, 4, or 5 small sardines 

 [Sardinops sagax] about 3 inches long" (November 24, 1910); 

 four days later, 13 murrelets were collected (November 28, 

 1910), and Beck noted, "Sardines 2 to 3 inches long in 

 stomachs"; then, on February 16, 1911, Beck reported, "A 

 six [inch] needle fish? [Strongylura exilis] swallowed by 

 Marbled Murrelet inside bill when picked up fish just caught"; 

 and finally, on March 1, 1911, a Marbled Murrelet was 

 collected with a "...6 1/2 [inch] fish in stomach" (table 1). 



The reference to the possible needlefish (California 

 needlefish = Strongylura exilis) is interesting because the 

 northern distribution limit for this species is San Francisco 

 (Miller and Lea 1972). Carter and Erickson (1988) thought 

 the fish may have been a sand lance. 



Carter and Erickson (1988) also reported on the food 

 habits of 10 murrelets which were collected in early fall 

 from northern Monterey Bay in the late 1970's. The murrelets 



232 



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



