86 William C. McComb and Robert L. Rumsey 



Birds were counted 15 times on each 0.4-ha plot from 15 January 

 to 5 March 1980 and 1981 (winter birds), and 13 times on each plot 

 from 20 March to 15 June 1980 and 1981 (breeding birds). Approxi- 

 mately 10 minutes were spent on the center of each plot during each 

 visit counting birds seen or heard on the plot. Locations of birds in the 

 plot were judged to be within 9 m of the plot edge or within the plot 

 center. Only winter birds observed foraging were assumed using a plot 

 while breeding birds which were either singing or foraging were tallied. 

 Birds were counted within three hours of sunrise or sunset. Eight morn- 

 ing and seven evening visits were made to each plot during winter, and 

 seven morning and six evening visits were made to each plot during the 

 breeding season. Shannon-Weaver BSD, equitability, richness, and 

 average density per plot per visit of each species were compared among 

 treatments blocking on aspects with analysis of variance and Duncan's 

 New Multiple Range Test. Tests among treatments are conservative due 

 to variability among aspects. Linear correlation was used to identify 

 plot characteristics potentially important in determining use by common 

 bird species. A t-test was used to compare weighted mean environmental 

 characteristics for plots used by a species vs. overall means and to com- 

 pare mean BSD, equitabiHty, richness, and density between seasons. 

 Chi-square analysis was used to compare occurrences of birds at the 

 edge vs. center of plots. 



RESULTS AND DISCUSSION 



Seasonal Effects. — Not unexpectedly, the breeding bird communi- 

 ties had higher diversity (x = 0.91 1), richness (x = 2.2), equitability (x = 

 0.238), and density (x = 2.4 birds/ 0.4 ha) than the winter bird commun- 

 ities (x = 0.265, 1.0, 0.069, and 1.0, respectively) (Table 2). Winter bird 

 communities were dominated by hairy woodpeckers, Picoides villosus, 

 and Carolina chickadees, Parus carolinensis (Table 2), and the breeding 

 bird communities were dominated by red-eyed vireos, Vireo olivaceus, 

 and hooded warblers, Wilsonia citrina (Table 3). Several resident spe- 

 cies changed their habitat usage from winter to spring. White-breasted 

 nuthatches, Sitta carolinensis, used areas in spring with a higher den- 

 sity (x = 1/43 m^) of larger diameter (x = 1.23 cm) snags and fewer trees 

 (x = 1/32 m^) than in winter (x = 1/171 m^, 7.9 cm and 1/27 m^ respec- 

 tively) (P<0.05). Red-bellied woodpeckers, Melanerpes carolinus, used 

 areas in spring with more snags (x = 1/50 m^), higher understory density 

 (x = 45.2 stems/ 4 m^), and lower foliage height diversity (x = 1.23) than 

 in winter (x = 1/171 m^ 34.7 stems/4 m^, and 1.40, respectively) 

 (P<0.05). Both white-breasted nuthatches and red-bellied woodpeckers 

 probably used areas with higher snag density in spring for nesting pur- 

 poses, since both will forage on dead or living trees in the winter 

 (Conner 1979). 



