Northern Prairie Wildlife Research Center
A total of 142 species of birds were recorded breeding on the study area during studies in 1979 and 1980. These records represent nearly 71% of the species breeding in Nebraska. The projected mean breeding population on the study area was estimated at about 2,900,000 pairs. By taxonomic order, in decreasing abundance, the most common groups of birds were Passeriformes, Columbiformes, Apodiformes, and Piciformes. These four orders accounted for 95% of the total breeding bird population. Fifteen families accounted for 95% of the total population; blackbirds (Icteridae) and sparrows (Fringillidae) were the most frequent families encountered, about 52% of the total. Weaver finches (Ploceidae), doves (Columbidae), flycatchers (Tyrannidae), thrushes (Turdidae), and swifts (Apodidae) composed an additional 26% of the bird population on the study area.
Thirty-four species accounted for approximately 95% of the total bird population (Table 8). Western meadowlarks, common grackles, and grasshopper sparrows constituted approximately 26% of the population with each having 248,000+ breeding pairs. House sparrows, mourning doves, and brown-headed cowbirds formed about 19% of the total population. The remaining 28 species were each represented by breeding populations that totaled less than 150,000 pairs.
Among the remaining species are several of special interest or having very limited breeding ranges. Included in this group are the burrowing owl, greater prairie chicken, long-billed curlew, and piping plover.
Burrowing owls occurred on only four census plots. Habitat use was restricted to upland native prairie in both the Sandhill Region and on fine textured soils in other areas. This species has been included for years on the Blue List, a system developed by the National Audubon Society to function as an early warning for species which may be approaching a critical status (Arbib 1978). The projected breeding population of burrowing owls on the study area was 3800 pairs.
Greater prairie chickens occurred on upland native prairie on sandhill soils. This species is nationally threatened (U.S. Bureau of Sport Fisheries and Wildlife 1973), endangered in certain areas and extirpated over most of its former range. An estimated 3800 pairs were present on our study area although none were present on plots in the Platte or North Platte River Valleys.
Long-billed curlews occurred on upland native prairie on both sandhill and fine textured soils. The greatest breeding density occurred in sandhill prairie. This species formerly bred throughout the prairie regions of North America, but its range is now markedly reduced (McCallum et al. 1977). The projected population on our study area was 2600 pairs. The breeding status of the piping plover is also of continental concern (Arbib 1978). The projected Platte River population was 120 breeding pairs.
Characteristic species breeding in each of the major natural habitat types of the Platte River Valley are shown in Fig. 18. Bird communities of both natural and man-created habitats on the study area are described in this section.
The highest densities of breeding birds on the study area were in shelterbelts (1361 pairs/40.5 ha or 100 acres). Shelterbelts were used by 31 species; 27 of these were considered nesting species. Twenty-five species attained their highest density in shelterbelts; mourning dove, common grackle, brown-headed cowbird, and northern oriole were most abundant.
River channel islands
Wooded islands in channels of the Platte River also received high use by breeding birds. Forty-seven species were recorded on river channel islands, and 35 were considered breeders. Mean density of breeding pairs was 212.4 pairs/40.5 ha (100 acres). The cliff swallow and common yellowthroat were the most numerous species. Piping plover, belted kingfisher, willow flycatcher, bank swallow, cliff swallow, Bell's vireo, common yellowthroat, cardinal, and indigo bunting attained their highest density on river channel islands. The piping plover was restricted exclusively to unvegetated and sparsely vegetated sandbars.
Lowland forest supported the greatest number of species on the study area. A total of 64 species were present; 50 were considered to be nesting. Fourteen species reached their maximum population density in this habitat type. The most abundant species were house wren, rnourning dove, American robin, and brown-headed cowbird. Eastern phoebe, eastern wood pewee, Bewick's wren, eastern bluebird, blue grosbeak, lazuli bunting, and rufous-sided towhee occurred only in this habitat type. The mean density of breeding birds was 202.4 pairs/40.5 ha (100 acres).
Lowland native prairie
Thirty-five species were recorded in lowland native prairie and 27 of these were considered breeders. The mean density of breeding birds was 47.4 pairs/40.5 ha (100 acres). Western meadowlark, grasshopper sparrow, red-winged blackbird, and brown-headed cowbird were the most numerous species. Upland sandpiper, bobolink, and eastern meadowlark reached their highest abundance in lowland native prairie. The eastern meadowlark was the only species restricted exclusively to lowland prairie.
Upland native prairie
Fifty-one species were recorded in this habitat type; 31 were considered to be nesters. Grasshopper sparrow, western meadowlark, and dickcissel were the most abundant species. Swainson's hawk, greater prairie chicken, sharp-tailed grouse, long-billed curlew, great-horned owl, burrowing owl, common nighthawk, and grasshopper, vesper, lark, field, Brewer's, and Cassin's sparrows reached their highest density in upland native prairie. Six species were restricted to this habitat. Mean density of breeding birds was 39.3 pairs/40.5 ha (100 acres).
Twenty-eight species were recorded in alfalfa fields of which 13 were considered nesting. The mean density was 41.3 pairs/40.5 ha (100 acres). Mourning dove, dickcissel, western meadowlark, and brown-headed cowbird occurred in highest densities. No species reached its maximum breeding density in alfalfa fields.
Corn and wheat fields
Eighteen species of birds were recorded in cornfields; horned lark, killdeer, and western meadowlark were considered breeders. The mean density of breeding birds was 15.3 pairs/40.5 ha (100 acres). The western meadowlark was the most numerous of the 3 breeding species. No species reached its highest density in cornfields.
Thirteen of 15 species recorded in wheat fields were considered to be nesting. The mean breeding density was 13.4 pairs/40.5 ha (100 acres), the lowest recorded for any habitat type on the study area. Lark bunting, western meadowlark, and the grasshopper sparrow were most abundant. Only one species, the lark bunting, reached its highest population density in wheat fields.