"We are interested in the landscape characteristics at two different scales," Stephens says. "We want to find out if the level of upland cover at a four-square-mile scale is more important than the amount of cover at that bigger scale and how it affects nest success in the core area."
Stephens and his two research crews went to work locating nests on the study sites during the spring of 2000. They searched fencerows, ditches, and other small patches of cover on foot. In larger areas, such as CRP fields and native pastures, they used ATVs and a chain. Blessed with excellent wetland conditions, they were able to obtain a large sample of duck nests, which they monitored throughout the nesting season.
The researchers also monitored the nests of any other grassland-nesting birds that they discovered, including sharp-tailed grouse, harriers, short-eared owls, and several species of shorebirds. By the end of the nesting season, it was clear that 2000 was a banner year for duck production in the Missouri Coteau. "Of the more than 2,200 duck nests that we monitored on all the study sites, we had an overall nest success rate of 22 percent," Stephens says. "Twelve of the 18 sites had nest success of more than 15 percent (the level required to maintain duck populations), including some sites that had very little cover. The most productive areas were those with more than 70 percent grass cover, which collectively had an average nest success of 32 percent. One of these sites had a phenomenal 43 percent nest success."
Nearly all duck species had good production in 2000 on Stephens' study areas. Pintails led the pack with an average nest success of 30 percent, followed by blue-winged teal (26 percent), gadwalls (20 percent), and mallards (19 percent). The only species that failed to hatch enough young to achieve population growth was the scaup. Stephens noted that their preference for nesting along wetland margins seemed to make the birds more vulnerable to predators such as skunks and foxes.