Taken from the NDGF website.
Duck Brood Index Down from Last Year
North Dakota's 2007 fall duck flight is expected to be down about 50 percent from last year and similar to the fall flight of 2004, according to Mike Johnson, game management section leader for the North Dakota Game and Fish Department.
Even though the 2007 brood index from the department’s annual mid-July survey was down from last year’s record high index, it is still 72 percent above the 1955-2006 average. Average brood size was 6.4 ducklings, down slightly from last year. The long‑term average is 7.1 ducklings per brood. The water index observed during the survey was up 84 percent from 2006, and 49 percent above the long-term average.
Average age of broods was similar to the long-term average, Johnson said. Brood survey results, Johnson expects, may be somewhat low due to tall dense vegetative cover on many wetlands and high water levels and flooded vegetation from heavy rains. Recent rains have improved brood habitat across much of the state and should improve the survival of late-hatched broods.
The index does not count every water body or duckling in the state. Instead, representative transects across the state are sampled each year. Over time, survey results provide biologists with trend information that allows annual comparisons of waterfowl production in the state.