Nelson and Hamer Chapter 5 



Table 8 Mean length of feeding visits at Marbled Murrelet nests by state and province' 



Nesting Biology and Behavior 



1 Data from Hamer and Cummins 1 99 1 ; Hirsch and others 1 98 1 ; P. Jones, pers. comm. ; Kerns, pers. 

 comm.; Nelson and Peck, in press; Ritchie, pers. comm.; Simons 1980; S.W. Singer, pers. comm. 



2 No tree nests with chicks were observed in Alaska. 



3 Adults may not have fed chicks fish on some of the shorter visits. 



head first and whole ( x = 1 .4 minutes at a nest in Washington, 

 n = 4 observations) (Hamer and Cummins 1991; Nelson and 

 Peck, in press). Adults usually leave within 1 minute of the 

 fish exchange. 



To provide chicks with fish at dawn, adults probably 

 forage at night, perhaps taking advantage of fish that forage 

 near the water surface during darkness (Carter and Sealy 

 1987a, 1990). Fish species that have been fed to chicks at 

 nests include Pacific sand lance (Ammodytes hexapterus), 

 Pacific herring (Clupea harengus), and northern anchovy 

 (Engraulis mordax) (P. Jones, pers. comm.; Nelson and 

 Peck, in press). Other potential prey species that were not 

 positively identified included capelin (Mallotus spp.), smelt 

 (Osmeridae; probably whitebait [Allosmerus elongatus] or 

 surf smelt [Hypomesus pretiosus]), and herring species 

 (Clupeidae or Dussumieriidae) (Naslund 1993a; Nelson, 

 unpubl. data; Simons 1980; but see Burkett, this volume). 



Flight Behavior 



Adult murrelets often use similar flight paths on 

 approaches and departures from tree nests. Generally, they 

 follow openings such as creeks, roads or other clearings that 

 allow for direct approaches and departures from the nest 

 (Kerns, pers. comm.; Nelson and Peck, in press; Singer and 

 others 1991; Singer and others, in press). The directions that 

 birds enter and leave nests appear to be related to openings 

 in the canopy or forest around the nest tree, and gaps in the 

 horizontal cover surrounding the nest limb (Naslund, pers. 

 comm.; Nelson and Peck, in press; Singer and others 1991; 

 Singer and others, in press). Birds approach nests below tree 

 canopy at heights as low as 5 m, and usually ascend steeply 

 to the nest in a "stall-out" fashion. Landings are sometimes 

 hard and audible (Nelson and Peck, in press; S.W. Singer, 



pers. comm.). We have observed and heard murrelets crashing 

 into tree limbs on some occasions during final approaches to 

 nests (Nelson and Peck, in press). In addition, birds 

 occasionally abandoned landings and circled around for second 

 attempts. When leaving the nest, birds usually drop 5-30 m 

 in height before ascending over the canopy to continue their 

 departure flights. They have not been observed departing at 

 nest height or flying upwards on take-off from the nest limb. 



When landing on the nest branch, murrelets splay out 

 their webbed feet, lean backwards, and use their wings to 

 slow their forward motion. They land hard enough on the 

 nest limb to create a landing pad, or area where the moss or 

 duff becomes flattened, removed, and worn by repeated 

 landings. Toe nail markings are evident at some landing 

 pads. Landing pads are most often located on the nest limb 

 within 1 m of the nest cup, however they have also been 

 located on adjacent limbs. In the latter case, murrelets hop 

 to the nest limb. 



Subcanopy behaviors, including one or more birds flying 

 through, into, or out of the tree canopy, and birds landing in 

 trees, are flight behaviors indicative of nesting and have been 

 noted in nest stands and around nest trees. Landings and 

 departures from trees have been observed at nests, on other 

 branches in nest trees, in trees adjacent to nest trees, and 

 other trees in nest stands throughout the breeding season. 

 These landings may indicate nesting, territorial behavior, 

 searches for nest sites, or resting or roosting behavior (Naslund 

 1993a). Singer and others (1991), and Naslund (1993a) 

 described an additional four flight patterns observed near 

 nest trees: (1) fly-bys and stall-flights, including single birds 

 or pairs flying by or stalling out next to a known nest tree, at 

 nest branch height; (2) flying-in-tandem and tail-chases, where 

 pairs of birds fly in close proximity to known nest trees; and 



64 



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



