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Platte River Status: A fairly common migrant and uncommon and local nesting species. Tout (1947) stated that loggerhead shrike was a regular summer resident in Lincoln County but never abundant. Occurrence dates in Lincoln County extend from 9 April to 29 October. Rosche (1979) found this species in the lower North Platte River Valley during 28 March to 25 August.

Breeding Range: An uncommon and local nesting species throughout the study area. Apparently occurs most frequently in the canyonland region of the Dissected Plain in southern Lincoln County, and in the lower North Platte River Valley. Regular during the nesting season on all other physiographic regions.

Breeding Population: The population in 1979-1980 was estimated at 135 nesting pairs. Our observations of the distribution of this species in the study area suggest that our population is underestimated by at least 50%. We base this conclusion on the difficulty of censusing a bird species that is essentially non- vocal during the nesting season, and that occurs in habitats that are not readily sampled with the census technique we used.

Habitat: The highest mean nesting density was 0.2 pairs per km² in wet prairie and in upland prairie. Loggerhead shrike appears to be particularly common in areas supporting brushy fence rows adjacent to agricultural lands and in thick wooded vegetation in the canyons of the Dissected Plain of southern Lincoln County. Rising (1974) stated that in western Kansas, loggerhead shrike prefers thickets of Prunus sp. Faanes (1982), however, reported that all loggerhead shrikes on a central North Dakota study area were associated with shelterbelts. Stewart (1975) classified loggerhead shrike as an open-country edge species across North Dakota.

Effect of Habitat Alteration: Because of the close affinity of this species for brushy edge habitats, especially those occurring in agricultural areas, we believe that loggerhead shrike has been negatively impacted in the Platte River Valley. The extensive plowing of natural habitats coupled with fence row removal associated with expanding field sizes, produces a negative impact on the stability of nesting habitats here. Overgrazing of brushy thickets on the Dissected Plain contributes similarly to habitat loss.

Nesting Data: Among the eight loggerhead shrike nests we have found in the study area, mean clutch size was 3.0 eggs during 3 May to 16 June. Lingle found a recently fledged brood of five on 3 June 1988 in T. 9 N. - R. 11 W., Hall County. Middleton (1943) chronicled the nesting activities of a loggerhead shrike pair in 1942 near Brady, Lincoln County. Courtship displays were first observed 28 March; a nest with eggs on 23 May. The breeding season in North Dakota extends from mid April to early August. Extreme egg dates in North Dakota are 18 April to 19 June (Stewart 1975). Kansas egg dates range from 1 April to 30 June (Johnsgard 1979).