Breeding Birds of North Dakota
American avocet (Recurvirostra americana (Gmelin))
Breeding Range (Fig. 70). Fairly common (locally common) on the Missouri Coteau; uncommon (fairly common locally) on the Northeastern, Southern, and Northwestern Drift Plains; rare in the Turtle Mountains; rare and local in the Agassiz Lake Plain Region (recorded in Grand Forks and Walsh Counties), on the Coteau Slope (recorded in Burleigh and Emmons Counties), and Missouri Slope (recorded in Adams, Bowman, and Slope Counties). In 1853, Suckley (1859) found this species to be very abundant along tributaries of the Sheyenne River, and along the Missouri River.
Breeding Habitat. Breeding pairs are largely restricted to ponds and lakes with exposed, sparsely vegetated shorelines or mud flats that are adjacent to expanses of shallow water. These conditions occur naturally on alkali ponds and lakes and on subsaline semipermanent ponds and lakes. During low-water conditions, exposed shorelines or mud flats also are created in other types of wetlands by certain types of land-use practices, particularly overgrazing and tillage.
During the period 1961-1969, the habitats occupied by 311 breeding pairs were recorded (H. A. Kantrud, RES). Of these, 253 pairs (81 percent) were found on saline or subsaline ponds and lakes, including 176 pairs (57 percent) on strongly saline alkali ponds and lakes, 76 (24 percent) on subsaline semipermanent ponds and lakes, and 1 pair on a subsaline permanent lake. A total of 58 pairs (19 percent) were found on fresh, slightly brackish, moderately brackish, or brackish ponds and lakes, including 33 pairs (11 percent) on slightly brackish, moderately brackish, and brackish semipermanent ponds and lakes with heavily grazed emergent vegetation; 17 pairs (5 percent) on fresh and slightly brackish seasonal ponds and lakes with heavily grazed emergent vegetation; 5 pairs (2 percent) on fresh and slightly brackish seasonal ponds and lakes with tilled bottom soils; 2 pairs on slightly brackish permanent lakes; and 1 pair on a sewage lagoon.
Breeding populations are usually represented by widely scattered, segregated pairs on fresh to brackish ponds and lakes, but on alkali lakes and on subsaline, semipermanent and permanent ponds and lakes, loose assemblages of breeding pairs often are present. In certain situations this species could even be considered as semi-colonial. In western Stutsman County, one of these semi-colonial groups occurs regularly in the middle of Chase Lake on an exposed spindle-shaped sand bar that is about 150 feet long and 30 feet wide at the middle (RES). On June 30, 1963, 13 active nests were found on this island, and on June 15, 1968, 20 active nests were present. Large numbers of Common Terns also were nesting on this island, and several nests contained eggs of both species.
Nesting. Breeding season: Early May to late July; peak, mid-May to early July. A pair was observed copulating on the early date of May 3 [1965] in Stutsman County (RES). Extreme egg dates (59 nests): May 12 [1963] in Stutsman County (RES) to July 5 [1898] in Benson County (Rolfe 1899b). Extreme dates of dependent young (48 broods): June 9 [1965] to July 27 [1964] in Stutsman County (H.A. Kantrud, RES). Adults were observed exhibiting territorial behavior as late as July 30 [1960] in Stutsman County (RES).
Nests are situated on mud flats or sand bars occurring as small islands, spits or shore zones. Nest sites are often on areas that are barely exposed above the water surface, and, occasionally, a stunted, open growth of emergent plants may be present.
Indicated clutch size (17 nests): 2 to eggs; mean, 3.1 eggs.
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| Figure 70. Breeding Range of American Avocet. |
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