Date of Award
Master of Science (MS)
School of Renewable Natural Resources
Rohwer, Frank C.
Wright, Vernon L.
Hohman, W. L.
I studied the effects of predator removal on survival and movements of Northern Shoveler (Anas clypeata) broods in the prairie pothole region of North Dakota. The study was conducted from April through August 1995. No treatment effects were found on brood survival as both 14 and 30 day survival estimates were statistically equivalent. Experimental sites had higher brood and duckling survival and produced twice as many fledglings per successful nest than control sites. Cumulative movement distance had no effect on duckling survival. While survival rates of Northern Shoveler broods and ducklings were higher than most species of prairie nesting ducks, Shovelers exhibited similar mortality patterns over the 30 day period. Predator reduction did not affect overland movements by Northern Shoveler broods. Frequency and cumulative distances traveled over 30 days did not differ between experimental and control sites. Distance moved between wetlands was significantly different between treatments, but it is unclear whether this was a result of predator reduction. Nest site selection and initial movements did not differ between control and experimental sites. Using pooled data, there was a highly significant difference was found between the mean distance from nest sites to the closest wetlands (41 m) and initial movements to water (555 m). Broods made similar numbers of movements during the first 15 days after hatch as days 16-30 after hatch. Densities of available wetlands did not differ for broods on experimental and control sites. Radio telemetry is a valuable tool in many studies of waterfowl ecology, but effects on behavior and survival of marked individuals, inadequate radio retention rates, and poor signal range potentially limit its usefulness. I used 8 g anchor transmitters and modified glue and suture attachment methods which were previously used on Mallards (Anasplatyrhynchos) but had poor retention rates with Northern Shovelers For smaller species of waterfowl, which have thinner skin than larger species, use of smaller anchor transmitters and avoidance of cyanoacrylate glue as an attachment supplement would most likely yield better retention rates.
Zimmer, John M., "Effects of Predator Reduction on the Survival and Movements of Northern Shoveler Broods" (1996). LSU Historical Dissertations and Theses. 8226.