Wildlife Surveys & Fall Flight Forecasting

August 29, 2013 by  

By Doug Leier

Hunters are not much different than sports fans when it comes to looking forward to upcoming seasons and learning about expert analysis and predictions. Fall flight forecasts for waterfowl and results from upland game brood surveys will pique the interest of hunters and wildlife managers alike.

Along the way, from crow and goose which began in mid-August to the close of turkey season in mid-January, there’ll be no shortage of questions about wildlife populations.

Wildlife surveys

For starters, there is a difference between how we try to estimate human and wildlife populations. Every 10 years the United States carries out a census during which an attempt is made to count every person in the country. This is not the case with most wildlife surveys. For example, an accurate census or actual count of sharp-tailed grouse in North Dakota is virtually impossible, due to their high numbers and broad range. Besides, it’s probably not necessary to know if we have 500,000 sharp-tails or 612,576.

For effective wildlife management, however, it is important to know some things about populations. Instead of an actual count, wildlife surveys typically provide a population index. For instance, the spring mule deer index is mule deer per square mile surveyed. The pheasant brood index is broods per mile of survey route. One fish population index is fish per net hour.

An index is a statistically accepted method as long as the survey is similar from year to year. That’s why the spring pheasant crowing count, for example, takes place during the same time frame and along the same routes from year to year. If the routes changed from year to year, and one year surveyors started each route at sunrise and the next year they all started their routes at noon, the results would not be comparable.

Conducting surveys and compiling their related indexes is a science, but that doesn’t mean that all hunters will experience season results that are in line with survey results. After all the numbers are crunched, wildlife populations still may vary depending on locale and species. For example, take the spring crowing counts for pheasants. The statewide index, which includes the average of all survey routes, decreased 11% from 2012 but that doesn’t mean pheasant hunters will shoot 11% fewer roosters this fall.

Game and Fish’s summer brood survey, that looks at upland game production, is still in progress through August so those results are not yet known.

Remember that any statewide index is an average. The big picture will also contain many other small areas where local weather conditions or habitat changes will yield a bird population – some lower, some higher – that is not in line with statewide predictions.

Waterfowl projections

Duck Brood Survey

North Dakota biologists estimate a significantly lower fall flight from the state in 2013

Based on statistics from the Game and Fish Department’s recently completed summer duck brood survey, plus results from the spring breeding duck survey, North Dakota biologists estimate a significantly lower fall flight from the state in 2013, but the number of ducks raised in North Dakota and heading south this fall will still be above the long-term average.

There may be other ducks nesting elsewhere that will migrate through North Dakota, to make up for fewer birds produced in the state this year.

Biological surveys give us a pretty good idea of what to expect, and overall, North Dakota hunters can look forward to a good fall. But individual success, as always, depends on when and where and the amount of effort invested.

The only way to find out is to take to the field in the coming months, and for most of us, that’s a sure thing.

Leier is a biologist for the Game and Fish Department. He can be reached by email: [email protected]


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