Research suggests that when nesting cover is reduced to remnant patches which
are easily searched by predators, duck nest success is greatly reduced. Predation
rates are particularly high in narrow wetland fringes which provide attractive
but not effective nesting cover. One of the management techniques utilized by
Ducks Unlimited is to lease or purchase riparian habitat, maintain idle cover,
and provide wider and perhaps more secure nesting habitat. The effectiveness
of this management option was tested at the Antelope Creek Ranch near Brooks,
Alberta, in 1988. Nest searches were conducted in wetland fringes and dry basin
bottoms. Wet meadow vegetation such as tall grasses and sedges dominated wetland
fringes while solid stands of cat tail dominated wetland bottoms. In wetland
fringes, predation rates declined with distance from nest to water. In the first
25 meters, 80% of all nests were destroyed by predators while 72% of nests initiated
between 25 and 50 meters from water were destroyed. However, the predation rate
was only 44% for nests initiated more than 50 m from water. Mayfield success
rates were 3, 7, and 21% in the three nest-water distance categories, respectively.
This indicates that nest losses can be reduced by managing riparian habitats
and providing wider zones of attractive cover further away from wetlands. Another
management option is manipulation of water levels to provide stands of tall
emergent vegetation for nesting. Predation rates in stands of dry cattail were
considerably lower than in wetland fringes and also seemed to vary with distance
between nest and water. Predation was highest (30%) for nests located in the
first 25 meters but declined to 25 and 20% for nests initiated 25-50 meters
and over 50 meters from water, respectively. Mayfield nest success ranged from
28% for nests located less than 25 meters from water to 39% for those initiated
more than 50 meters from water. It appears that providing wider wet meadow zones
around wetlands or dry stands of tall and dense emergent vegetation can be effective
in reducing nest losses to predation.
Previous Section -- Overwater Nest Structures for Ducks
and Geese Return to Contents Next Section -- Scent Station Surveys in Minnesota with
Reference to Predator Management