Some effects of fluctuating and falling water levels on waterfowl production

Publication Type:

Journal Article

Authors:

Wolf, Ken

Source:

Journal of Wildlife Management, Wiley for The Wildlife Society, Volume 19, Issue 1, p.13-23 (1955)

Call Number:

A55WOL01IDUS

URL:

http://www.jstor.org/stable/3797548

Keywords:

American coot, Anas acuta, Anas cyanoptera, Anas platyrhynchos, Aythya affinis, Aythya americana, Aythya valisineria, canvasback, cinnamon teal, Fulica americana, Lesser Scaup, Mallard, northern pintail, Oxyura jamaicensis, pied-billed grebe, Podilymbus podiceps, redhead, Ruddy Duck, Western Grebe

Abstract:

Three areas in the Cache Valley (mostly northern Utah but extending into southern Idaho) were selected for a study in September 1951 to determine the effects of fluctuating and falling water levels on waterfowl production: Swan Lake (ID, stable water levels), Newton Reservoir (UT, water level that drops as much as 15 ft during nesting season), and Cutler Reservoir (UT, fluctuating water levels). Direct damage was caused to eggs by partial or complete submergence. Nests that were built up as the water level rose were generally unstable when the water receded. Both mallards and redheads attempted to save their clutches by building nests higher. Flooding caused a loss of 31% of potential waterfowl production on Cutler Reservoir. The losses occurred throughout all stages of incubation and hatching. Loss among coot nests accounted for only 6% of the total loss to potential waterfowl production on Cutler Reservoir from water level changes. At Newton Reservoir there was evidence of nest desertion when the water level dropped 4 ft or more. Fifty percent of mallard nests on Cutler Reservoir suffered partial or complete damage; 57% of these were completely destroyed. Thirty-nine percent of all mallard eggs were lost due to the effects of water. All were at least partially damaged by maximum rises of 1.08 and 2.58 ft. A rise to about 2 ft was the maximum tolerable for this species. Ninety percent of all redhead nests were subjected to flooding, but in contrast to mallards, not a single instance of complete loss occurred. Forty-six percent of all redhead eggs were lost due to effects of water. Redhead nests were partially damaged by rises of 1.03 to 2.11 ft; a rate of rise of 0.166 ft per day for 5 days killed 40% of eggs in flooded nests. The data obtained for this study indicated little or no difference in survival between the areas of falling, stable, and fluctuating water levels.