Effects of Weather on Breeding Ducks in North Dakota
Study Areas
The dependence of waterfowl on aspects of spring weather for the timing of arrival and the onset of breeding activities has long been part of biological folklore. Despite an awareness of these associations, relations between weather and waterfowl biology have rarely been quantified, partly because studies were too short to elucidate clear dependencies. We examined the effects of temperature and precipitation on waterfowl arrival, nesting, and production on two breeding areas in North Dakota. Dates of arrival, initiation of first nests, and peak hatching, as well as length of period of most active nesting, productivity, and brood size, were studied in the mallard (Anas platyrhynchos), gadwall (A. strepera), blue-winged teal (A. discors), and redhead (Aythya americana).
Study Areas
The areas we studied were on the J. Clark Salyer National Wildlife Refuge (Salyer) in Bottineau and McHenry counties, and at the Woodworth Station, a field station of the Northern Prairie Wildlife Research Center in Stutsman County, about 200 km southeast of Salyer. Basic climatological information is provided in Table 1; further details were presented by Jensen (1972).Wetlands at Salyer are mainly impounded marshes managed with water control structures on the Souris River. At Woodworth, however, the wetlands are natural and include most of the classes described by Stewart and Kantrud (1971), although only a few are semipermanent or permanent.
| Climatological information | Study area | |
| Salyera | Woodworthb | |
| Mean Temperature (°C) | ||
| March | -7.6 | -5.7 |
| April | 3.7 | 4.6 |
| May | 11.0 | 11.4 |
| June | 17.0 | 17.3 |
| Mean precipitationc (cm) | ||
| March | 5.1 | 5.1 |
| April | 6.4 | 8.4 |
| May | 13.0 | 14.2 |
| June | 23.9 | 21.8 |
| aSalyer
elevation=434 m. bWoodworth elevation=582 m. cInterpolated from graphs in Jensen (1972). |
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