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Platte River Status: A fairly common migrant and uncommon nesting species in the western half of the study area; local in the east. Blue grosbeak is an uncommon summer resident in Lincoln County, present during 15 May to 5 September (Tout 1947). Rosche (1979) observed blue grosbeak in the lower North Platte River Valley only once, on 6 June 1973, at Ash Hollow, Garden County.

Breeding Range: An uncommon nesting species in the Dissected Plain of southern Lincoln County, and along the Platte River Valley west to the edge of the study area; local in the Eastern Plain physiographic region and along the eastern reaches of the Platte River Valley.

Breeding Population: The estimated breeding population of 1979-80 was 700 breeding pairs. Given the distribution of blue grosbeak within the study area, we believe our population figure is slightly underestimated.

Habitat: We recorded a mean density of 0.7 pairs/km² in lowland forest. Blue grosbeak was observed frequently in thick willow growth on river channel islands and in dry canyons of Rocky Mountain juniper along the North Platte River. Rising (1974) considered blue grosbeak a summer resident in rank growths of riparian vegetation in western Kansas.

Effect of Habitat Alteration: Blue grosbeak has benefited from the establishment of lowland forest vegetation within channels of the Platte River, along with establishment of thick growths of willow vegetation on river sandbars. Heavy livestock grazing within the riparian zone, and in the dry canyons of the Dissected Plain physiographic region, may produce a negative impact on this species.

Nesting Data: Tout (1947) found a blue grosbeak nest with three eggs near Brady, Lincoln County, on 22 June 1940. Middleton (1947) reported that blue grosbeak nested for eight consecutive years in a Lincoln County yard. Kinch (1947) found a pair of blue grosbeak nesting in a lilac bush in Lexington, Dawson County in 1947. Most nesting in western Kansas occurs during mid June to mid July (Rising 1974). Johnsgard (1979) reported Kansas egg dates from 21 May to 30 June.