Grenier and Nelson 



Chapter 19 



Inland Habitat Associations in Oregon 



Table 3 Habitat characteristics of 75 Marbled Murreltt occupied sites and 225 random sites on the Siuslaw National 

 Forest, Oregon, 1981-1984. Data are from the Ecology Program Intensive and Reconnisance Plots database, 1993. 

 See appendix 3 for variable definitions 



0.0414 



14-134 



TBAD 



34 



1 Significant difference between occupied and random sites (P < 0.05. Kiuskal- Wallis test) 



Nest Sites 



Twenty -two nests were found between 1990 and 1993. 

 Ten nests were located by observing adult Marbled Murrelets 

 landing in or departing from a nest tree, three were found 

 after finding eggshell fragments on the forest floor, six were 

 located during the intensive tree climbing study, and three 

 were found while reclimbing known nest trees. Overall, nine 

 nests were confirmed active when discovered (Nelson and 

 Peck, in press). Of these, four were in the egg stage and five 

 were in the nestling stage. Nestlings were thought to have 

 fledged from three of these nests (see Nelson and Hamer. 

 this volume a; Nelson and Peck, in press). 



Nest and Nest Tree Characteristics 



All nests were located in trees >127 cm in d.b.h. (Jc = 

 187.9. s.e. = 9.4) and >36 m tall (x= 65.5, s.e. = 2.4; table 

 5). Twenty nests were found in Douglas-fir, one was found 

 in a Sitka spruce, and one was found in a western hemlock. 

 Nests generally consisted of depressions in a moss mat 



(average moss depth = 5.3 cm), but compacted duff (needles, 

 lichen, debris) substrates were also used. Nest cups averaged 

 1 2.0 x 1 1 . 1 cm (length x width) and were located on platforms 

 considerably larger than the nest ( x = 42.2 x 31.7 cm, s.e. = 

 4.2 and 2.9, respectively). The placement of nests on nest 

 branches was variable, ranging from 1 to 762 cm from the 

 trunk of the tree (x= 101.3, s.e. = 35.7). The nest in the 

 Sitka spruce was furthest from the tree trunk (at 762 cm); all 

 other nests were located <230 cm from the trunk. Nest 

 height ranged from 18 to 73 m above the ground ( x = 50.3, 

 s.e. = 2.4; table 5). 



Nest Stand Characteristics 



Nest stands generally consisted of 2 to 3 canopy layers 

 (x = 2.2, s.e. = 0.09, n = 10). Trees <45 cm d.b.h. were most 

 numerous (94.3 trees/ha), followed by trees >81 cm d.b.h., 

 and trees 46-80 cm d.b.h. (64.3 and 39.7 trees/ha) (table 6). 

 There were 7. 1 (s.e. = 1 .7) standing snags/ha in nest stands, 

 with a mean height of 15.5 m (s.e. = 2.1) and mean d.b.h. of 



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



197 



