Northern Prairie Wildlife Research Center
Breeding Range. (Fig.11). During recent years, the largest segment of the breeding population in North Dakota has become established as scattered colonies along the margin of Lake Sakakawea or Garrison Reservoir. Other recent colonies have been found on the Oahe Reservoir about 10 miles below Bismarck and on scattered lakes and river impoundments located within the Prairie Pothole Region and in the Turtle Mountains. These include Harriet Lake in Burleigh County, Chase Lake in Stutsman County, Upper Souris National Wildlife Refuge in Renville County, J. Clark Salyer National Wildlife Refuge in McHenry County, Willow Lake in the Turtle Mountains of Rolette County, East Devils Lake in Ramsey County, Ashtabula Reservoir in Griggs County, and lakes in southwestern Richland County, southeastern Sargent County, and west-central Dickey County.
Prior to 1926, colonies also were established in other localities of the state. These include Devils Lake (Bailey 1918d, Job 1898, Judd 1917, Rolfe 1898a, Simpson 1912, and Thompson 1932); Stump Lake in Nelson County (Bailey 1916a, Bent 1922, Job 1898 and 1902, Judd 1917, Lewis 1929, Reed 1904, and Rolfe 1898a); and Sweetwater Lake in Ramsey County (Bishop egg collection catalog, Jacobs 1898, and Wood 1923). The Devils Lake Colony on Bird Island was active through 1920 when a photograph of active nests was taken by C. Thompson (Wood 1923), and the Stump Lake Colony was found to be active as late as 1925 by Francis M. Uhler (Lewis 1929).
High populations recorded for several colonies are indicated as follows:
500 active nests at Chase Lake, Stutsman County on June 27, 1967 (A. D. Kruse).Breeding Habitat. Two very distinct nesting habitats are utilized by Double-crested Cormorants in North Dakota. Along the Missouri River reservoirs, all of the colonies were situated in the tops of dead trees, chiefly cottonwoods. This temporary habitat type was created when the tree growth along the Missouri River was inundated by rising impounded waters. Colonies located on natural lakes were nearly all situated on the ground on isolated islands. An exception was one colony observed on Sweetwater Lake in 1897 by Edwin S. Bryant. This colony was situated in willows that were growing in water 3 1/2: feet deep (Bishop egg collection catalog, Peabody Museum). On the shallow river impoundments of Upper Souris and J. Clark Salyer National Wildlife Refuges, colonies occurred on man-made islands and in groves of dead trees.340 active nests in one colony on Willow Lake in Turtle Mountains within Rolette County on June 5, 1969 (R. E. Stewart, Jr.).
200-300 active nests in one colony on Lake Sakakawea or Garrison Reservoir (Township T150N, R9lW) in 1970 (G. W. Enyeart). Mr. Enyeart estimated about 1,260 breeding pairs on all of Lake Sakakawea in 1958.
225 active nests on the Upper Souris National Wildlife Refuge, Renville County, on June 12-13, 1965 (D. A. Anderson); 150 active nests on this refuge in 1972 (I. O. Rostad).
170 active nests on J. Clark Salyer National Wildlife Refuge, McHenry County in 1946 (M. C. Hammond).
73 active nests on Stump Lake, Nelson County, on May 31, 1901 (Job 1902).
30 active nests on Sweetwater Lake, Ramsey County, on June 18, 1897 (E. S. Bryant - Bishop egg collection catalog, Peabody Museum).
30 active nests on Harriet Lake, Burleigh County, on August 1, 1968 (W. J. Stewart).
25 active nests on Creel Bay of Devils Lake in 1918 (Bailey 1918d).
Several of the island colonies were located on strongly brackish or saline lakes that did not contain populations of fish or salamanders. Adults from these colonies frequently travelled as much as 40 miles in order to reach adequate supplies of those important food organisms.
Nesting. Breeding season: Mid-April to early August; peak, late April to mid-July. Extreme egg dates (hundreds of nests): May 13 [1901] at Stump Lake, Nelson County (A. C. Bent) to July 18 [1917] at Stump Lake (H. C. Oberholser). Extreme dates of dependent young (hundreds of small young segregated in nests, or larger young grouped in pods): May 31 [1901] on Stump Lake (Job 1902) to July 25 [1900] on Stump Lake (Wood 1923).
Nests of this species ordinarily are well constructed. Sticks are the principal building materials in tree nests, while ground nests are composed chiefly of coarse weed stalks. The rims of ground nests are usually several inches above the ground.
Indicated clutch size (51 nests): 4 to 7 eggs; mean, 4.6 eggs. One set of nine eggs collected from one nest on Stump Lake in 1905 probably was produced by two breeding females (Bishop egg collection catalog, Peabody Museum).
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| Figure 11. Breeding Range of Double-crested Cormorant. |
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U.S. Department of the Interior |
U.S. Geological Survey
URL: http://www.npwrc.usgs.gov/resource/birds/bbofnd/species/1200.htm
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