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vegetation differences found along the transacts. Large trees lined • <br />the north bottomland transact whereas the south bottomland transact <br />resembled a moist grassy meadow with few stands of trees. <br />The most abundant birds along the north transact, warbling vireos <br />(Vireo is lvus) and yellow warblers (Dendroica oetechia), are most <br />commonly associated with wooded areas. The green-tailed towhee, which <br />frequents shrubs and dense underbrush, was the most common species on <br />the south transact (Table 8). <br />Seven of the species observed in bottomland were not seen in any <br />other habitat during breeding bird surveys (Table 7). Two of those <br />species, the yellow warbler and American goldfinch (Carduelis <br />tristis), appeared to be particularly attracted to bottomland and were <br />regular in this habitat. The other five species were only occasional- <br />Ty observed in bottomland. Cooper's hawks were exclusively seen in • <br />bottomland during breeding bird surveys, but were found nesting in <br />aspen and were often observed in other habitats during field studies. <br />Mountain brush <br />Species composition varied considerably between the two mountain <br />brush plots. Only seven of the 20 species recorded in this habitat <br />were seen on both plots (Table 9). Seven species were recorded only <br />in the north plot and six species were found solely in the south plot. <br />Although mountain brush had the second highest species diversity, <br />the plots yielded the lowest abundance. On both mountain brush plots, <br />10.3 birds were seen per day (Table 9). It is likely that the actual <br />number of birds was greater than those observed. Undercounting proba- <br />bly occurred, because it is likely that many non-singtng birds were • <br />36 <br />