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Platte River Status: A common migrant and fairly common summer resident. Occurrence dates on the Mormon Island Crane Meadows, Hall County, are from 22 April to 17 October. In Lincoln County, field sparrow is a local summer resident occurring 19 April to 12 October (Tout 1947). Rosche (1979) reported field sparrow from the lower North Platte River Valley during 3 June to 15 October.

Breeding Range: Locally common in the canyonlands of the Dissected Plain of southern Lincoln County, and along the Platte River west to Lake McConaughy. Fairly common elsewhere in the Dissected Plain and Eastern Plain; uncommon and local in the Sandhills and Western Plain.

Breeding Population: The estimated breeding population in 1979-80 was 2,820 pairs. Because of the wide distribution of this species in the study area, we believe that our population estimate is a minimum.

Habitat: We found largest breeding densities in upland prairie (1.0 pairs/km²) followed by lowland forest (0.7 pairs/km²) and river channel island (0.7 pairs/km²). Thickets of Prunus sp. and woodland edges provide suitable nesting habitat in western Kansas (Rising 1974). Stewart (1975) described optimum field sparrow nesting habitat in western North Dakota as dwarf sage flats on valley floors. Characteristic vegetation of the silver sage flats included native grasslands that are partially covered by an open canopy of low shrubs, dwarf sage and eastern pricklypear. We found most field sparrows during the nesting season at the edge of native grasslands being invaded by Rocky Mountain juniper, and containing an abundance of soapweed yucca. Shrubby thickets and field edges were particularly attractive to this species in the Dissected Plain. Nesting in the Platte River Valley was restricted primarily to extensive growths of willow samplings on river channel islands. Three nests found in western North Dakota in dwarf sage and western snowberry were less than one meter from the ground (Stewart 1975). Field sparrow appears to be very opportunistic in its selection of nesting habitat including shrub-grassland (Best 1979), brushy stands with little or no overstory (Crawford et al. 1981), shrubby fields (Johnston 1947), early successional stages (Shugart and James 1973), and grasslands with a few large trees (Sousa 1983). Field sparrow was classified a typical forest edge species by Johnston (1947). Apparent from the above information is that a mixture of shrubby and herbaceous vegetation is an essential component of field sparrow habitat.

Effect of Habitat Alteration: Nesting field sparrows, especially those on river channel islands, have benefited from de-watering of the Platte River system and the subsequent encroachment of wooded vegetation. Excessive grazing of grasslands and adjacent wooded thickets may result in a negative impact on this species in areas of limited wooded vegetation growth. Graber and Graber (1963) cited habitat loss, particularly orchards, as responsible for the 50% reduction in Illinois field sparrow populations between 1909 and 1957.

Nesting Data: We have no confirmed records of nests or young in the study area. Kansas egg dates range from 21 April to 10 September. This species is often double and triple brooded (Johnsgard 1979).