Harner and Nelson 



Chapter6 



Characteristics of Nest Trees and Nesting Stands 



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80 120 160 200 240 280 320 360 400 440 480 520 560 

 NEST TREE DIAMETER (cm) 



Figure 4 The diameter at breast height for 46 nest trees of the Marbled Murrelet found 

 in Califor- :<, Oregon, Washington, and British Columbia. The number of nest trees was 

 listed in 20-cm increments beginning with trees 70-80 cm in diameter. 



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5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 

 LIMB DIAMETER AT NEST (cm) 



Figures The diameter of the tree limbs under or nextto41 nests of the Marbled 

 Murretet found in California, Oregon, Washington, and British Columbia The 

 number of nests was listed in 5-cm increments beginning with limbs 0-5 cm 

 in diameter. 



The condition of the nest branches for nests in the Pacific 

 Northwest varied from healthy limbs (70 percent) to those 

 reported as declining (27 percent) or dead (3 percent) (n = 37). 

 Nest limbs with broken ends were reported in 16 percent of 

 the records (n = 37). In Alaska, 50 percent of the nest branches 

 were recorded as declining, 7 percent were reported with 

 broken ends, with 1 nest located on a dead branch (n = 14). 



The position of the nest on the tree bole was calculated 

 by dividing the nest height by the total tree height. Nests in 

 the Pacific Northwest were located an average of 68 percent 

 up the bole of the nest tree (table 3). Fifty-nine percent of the 

 nests were located in the top one-third of the tree bole, and 

 87 percent of the nests were located in the top one-half of the 

 tree. No nests were located lower than 40 percent of the total 



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



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