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• use and a description of the species of birds that occupy the mine complex. <br />Bird Abundance and Diversity by Habitaf <br />Differences in bird abundance and diversity among all habitats were not <br />significantly different using a two-way analysis of variance. However, species <br />richness (number of bird species present in area is significantly different (p<0.05) for <br />different habitat types and for different seasons. <br />Riparian - In terms of summer bird use the riparian area supports the <br />the highest abundance, diversity, (Exhibit 2.7-3) and species richness (85 species). <br />Thus, it can be considered the most important habitat type as the summer is usually <br />when habitat requirements for birds are the most stringent. Summer bird abundance <br />is 73 percent above that found in the aspen, although diversity is only 9 percent <br />higher. The high bird abundance in the riparian area probably reflects a high <br />productivity of The vegetation and a high availability of invertebrates, both important <br />food sources for birds. The high diversity of birds reflects the presence of four <br />distinct groups: species found in willows, species that use the sedge, species that use <br />• the edge between the sedges and willows, and species from adjacent habitats that use <br />the riparian area occasionally. In winter (Exhibit 2.7-4), abundance of birds drops in <br />the riparian area. This reflects The general pattern of decrease in abundance and <br />diversity in the study area in winter (Exhibit 2.7-5). Although diversity drops in <br />winter it remains higher in the riparian habitat than in other habitats. <br />Sixteen bird species were observed exclusively in The riparian area and may be <br />dependent on the riparian area for their presence. The birds include seven species <br />of waterfowl, the spotted sandpiper (Actitus macularia), the poor-will (Phalaenoptilus <br />nuttallii), two warblers, and five other passerine species. <br />The riparian area is considered an important habitat not only because of its <br />high bird abundance, but also because of its limited extent. Riparian habitat covers <br />only a small portion of the permit area, but it is important in adding diversity to the <br />entire area. The high productivity of plant and animal populations in this area <br />supplies energy in the form of food to adjacent areas. Red-tailed hawks (Buteo <br />jamaicensis) and northern harriers (Circus cyaneus), in particular, are often seen <br />hunting in the riparian areas. <br />Aspen - Aspen ranks second in bird diversity during the summer <br />• (Exhibit 2.7-3). This reflects the foliage height diversity, which is probably higher <br />than other communities because of the existence of three layers: a tree canopy <br />2.7 -6 <br />