Endemicity and Regiona Biodiversity in Nebraska\u27s Breedin Avifauna

I estimate that 215 bird species currently breed or have previously bred in Nebraska. This number compares with a total of 330 species that breed or have bred in the Great Plains region south of Canada, as I defined that region in my book on the breeding birds of the Great Plains (Johnsgard, 1979). Grasslands or potential grasslands make up about 81 percent of the Great Plains\u27 vegetation, and probably represented about 96 percent of Nebraska\u27s original vegetation. Only in the Sandhills region is that vegetation type still essentially intact; the tall-grass prairie of eastern Nebraska is Virtually gone. In my 1979 summary, I judged that 36 species of Great Plain\u27s bird are grassland-adapted forms, with 15 of these endemic to the Great Plains, and the rest more broadly distributed. Nine of these endemics breed in Nebraska (Greater Prairie-Chicken, Mountain Plover, Long-billed Curlew, Upland Sandpiper, Dickcissel, Lark Bunting, Clay-colored Sparrow, Cassin\u27s Sparrow, McCown\u27s Longspur and Chestnut-collared Longspur), and the Chihuahuan Raven also once did. None of these ten species is considered endangered nationally, although the Greater Prairie-Chicken needs to be monitored closely. Birds of the tall-grass prairie that currently breed in eastern Nebraska include the Upland Sandpiper, Dickcissel. Eastern Meadowlark, Field Sparrow and Henslow\u27s Sparrow. Both of the latter are not, strictly speaking, prairie species, but either represent a later successional stage containing some small trees (Field Sparrow), or the presence some brushy or weedy elements (Henslow\u27s Sparrow). In the west the short-grass plains support several declining or rare species, including Ferruginous Hawk, Swainson\u27s Hawk, Prairie Falcon, Mountain Plover, Burrowing Owl, Common Poor-will, Lark Bunting, and two longspurs. Some of these also have certain additional non-vegetative needs such as cliff-side nest sites (Prairie Falcon), burrows (Burrowing Owl), nearly bare ground (Mountain Plover), or rocky substrates (Poor-will). The geographically and ecologically intermediate Sandhills prairies support many typical grassland and wet meadow breeders, such as Sharp-tailed Grouse, Long-billed Curlew, Bobolink, Lark Sparrow, Grasshopper Sparrow and Horned Lark. Woodlands and forests comprise about 15 percent of the native vegetation of the Great Plains states, and support some 51 percent of the region\u27s breeding avifauna (Johnsgard, 1979). I estimate that in Nebraska this vegetation type occupies three percent of the state\u27s surface area, and supports 48 percent of its avifauna. It is thus one of the most important vegetation types for generating species diversity of our avifauna. Bald Eagles are among the rare woodland-nesting species of Nebraska, although they are also strongly water-dependent for food. Several hawks (Broad-winged, Red-shouldered, Cooper\u27s, etc.) are other clear associates of mature woodlands. Several woodland nesting passerines that have generally large ranges elsewhere in the central or western states are limited to woodlands in extreme northwestern Nebraska\u27s Pine Ridge region, or in the lower Missouri woodlands of extreme southeastern Nebraska (see Table 2 )