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Platte River Status: A common migrant and nesting species in the western half of the study area; rare and local in the east. The lark bunting was first described to science from a specimen collected by Townsend along the Platte River in 1837 (AOU 1983). Tout (1947) recorded lark bunting in Lincoln County during 8 May to 24 September, stating that the species was regularly a common nesting bird in his area. Rosche (1979) considered lark bunting a summer resident, present 6 May to 20 September, in the lower North Platte River Valley.

Breeding Range: A locally abundant nesting species in the Sandhills and Western Plain physiographic regions; common on the Dissected Plain; uncommon and highly local in the Eastern Plain and Platte River Valley physiographic regions.

Breeding Population: The breeding population in 1979-1980 was estimated at 103,500 pairs, which made up 3.5% of the total breeding bird numbers on the study area. Lark bunting ranked 9th in total abundance among all breeding bird species present.

Habitat: Lark bunting is a characteristic nesting species of shrub-dominated grasslands. In our study area, we found highest breeding densities in wheat (22.5 pairs/km²), principally in Deuel, Garden and Keith counties. Mean breeding density in upland prairie was 15.7 pairs/km². Lowest breeding densities occurred in alfalfa (3.2 pairs/km²), and wet meadow (1.0 pairs/km²). Stewart (1975) reported that disturbance habitats including weedy roadsides, retired cropland, weedy fallow fields, and alfalfa fields were used extensively for nesting in North Dakota. Kantrud and Kologiski (1982) found highest breeding densities among lark buntings on northern Great Plains grasslands were in heavily grazed tracts associated with high-moisture soils. Grazing intensity apparently resulted in much lower populations on warm, dry soils, such as those occurring across much of our Platte River study area. Dominant vegetation of native grasslands supporting large numbers of breeding lark buntings included western wheatgrass, eastern pricklypear and black sage. Other plants indicative of optimum lark bunting habitat included crested wheatgrass, buffalograss, red three-awn, prairie sandreed, green needlegrass and dwarf sage (Kantrud and Kologiski 1982). Shaded nest sites are an important component of lark bunting habitat (Baldwin et al. 1969, Creighton 1971, Creighton and Baldwin 1974, Pleszczynska 1978). Plant species such as black sage, dwarf sage, soapweed yucca, various cacti, and taller grasses appear to fulfill this requirement. Apparently the clumped arrangement of wheat stubble that has been disturbed by digging, supplies some of the nest site shading required by this species.

Effect of Habitat Alteration: We found highest mean breeding densities in wheat stubble fields which suggests that habitat alteration may benefit this species. Although we have no comparative data, general observation suggest that wheat fields are not stable habitat because crop management requires frequent disturbance of stubble fields, and wheat in Nebraska is usually harvested during mid to late June, at about the time most lark bunting eggs are due to hatch. The comparative stability of breeding populations in native grasslands suggests that although large numbers of lark buntings nest in disturbance habitats, native habitats are more beneficial as secure nesting habitat. Therefore, conversion of upland native grassland habitats has a long-term negative impact on this bird. Because of the low level of use made of wet meadow habitat, we have no basis for evaluation of the impact of wooded vegetation encroachment.

Nesting Data: Five active nests found 15 June 1979 in Gosper County each contained 5 lark bunting eggs; one nest contained 2 brown-headed cowbird eggs. Benckeser (1957) reported a lark bunting nest with 5 eggs from Brule, Lincoln County on 18 June 1955. The nest, containing 6 eggs, was found among eastern pricklypear vegetation in native grassland. Stewart (1975) reported that mean clutch size among 20 lark bunting nests in North Dakota was 3 eggs. Johnsgard (1979) reported that Kansas nests are initiated as early as 11 May, and completed as late as 20 June. The bulk of lark bunting broods in western Kansas occur 10 to 20 June (Rising 1974).