Northern Prairie Wildlife Research Center
Breeding Range. (Fig. 41). Fairly common throughout the Prairie Pothole Region and Southwestern Slope Region; rare and local on the Agassiz Lake Plain--recent records from Grand Forks and Richland Counties.
During the summer of 1873, Coues (1878) reported this species as being very abundant from Pembina west through the Mouse River Area. It was also reported as an abundant summer resident in Towner County during 1890-1895 but became quite rare by 1910 (Judd 1917). According to Williams (1926), a noticeable decrease in numbers occurred in the Grafton area of Walsh County after the early 1900's.
Breeding Habitat. Expanses of native prairie or cropland that include thickets of natural tree growth or brush margins of native forested tracts. Agricultural areas that contain established plantings of trees, including shelterbelts and tree claims, also are frequently occupied.
Nesting. Breeding season: Late April to early September; peak, mid-May to late July. Extreme egg dates (47 nests): April 29 [1968] in Sargent County (RES) to July 15 [1873] in Cavalier County (E. Coues). Extreme dates of nestlings (8 nests): July 1 [1969] in Stutsman County (B. E. Burkett) to August 15 [1873] in Bottineau County (Coues 1874a). Dependent young out of the nest were recorded on August 7 [1968] in Barnes County (H. F. Duebbert), on August 17 [1961] in Stutsman County (RES), and on September 5 [1974] in Kidder County (J. T. Lokemoen, RES).
Detailed accounts of 34 nest locations show that they were situated as follows: six each in American elm and bur oak; three each in peachleaf willow, cottonwood, and undetermined shrubs; two each in ponderosa pine, quaking aspen, box elder, green ash, and on the ground; and one each in hawthorn, wild plum, and balsam poplar. The height of 33 nests above the ground ranged from 0 (on ground) to 60 feet and averaged 20 feet.
Two ground nests with eggs were found on the treeless prairie northwest of Mandan in June, 1882 (Roberts 1932). In northeastern McKenzie County during 1912-26, this species was found nesting in the cottonwoods or other tall trees or on the cliffs in the badlands (Larson 1928). During mid-June, 1892, Bryant (1894) found several nests not over 6 feet above the ground in bushes that bordered Lake Alice in Ramsey County. In Towner County during 1890-1895, nesting was recorded wherever bushes occurred that were large enough to support nests; one nest about 3 feet above the ground was photographed (Judd 1917). Nesting sites in North Dakota in 1880 were reported by Capt. B. F. Goss (Bendire 1892) as follows: in the high timber along the streams from 40 to 60 feet up and in low brush patches on the prairies where the nests were but 2 to 4 feet above the ground. Goss also found prairie nests on the ground in areas where the brush patches had been destroyed by fire.
Indicated clutch size (16 nests): 2 to 4 eggs; mean, 3.0 eggs.
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| Figure 41. Breeding Range of Swainson's Hawk. |
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U.S. Department of the Interior |
U.S. Geological Survey
URL: http://www.npwrc.usgs.gov/resource/birds/bbofnd/species/3420.htm
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Menlo Park, CA [caww54]
