The outlook for this autumn’s hunting season is bleak. Declining numbers of breeding ducks, coupled with drought conditions on the northern prairies, will result in the smallest fall flight in years.

That is the grim news from this spring’s aerial survey of the North American breeding grounds.

Ducks returning northward this spring were greeted by record low numbers of potholes in Canada – and the second lowest number ever recorded for both Canada and the United States. This tells us the production of young will be severely depressed. Few young-of the-year ducks will be fledged and adult ducks will probably outnumber juveniles in this autumn’s southward migration.

Biologists counted only 1.4 million potholes in Canada (a record low) and 1.3 million in the Dakotas and eastern Montana. The combined North American total of 2.7 million is the second-lowest ever recorded. This represents a 64 percent decline from the 7.4 million potholes found in 1996.

North American pothole numbers since 1994, the year water returned to the prairies after the prolonged drought of the ‘80s and early ‘90s, are shown in the following graph.

North American Potholes

1994 1995 1996 1997 1998 1999 2000 2001 2002

Year

Populations of breeding ducks fared somewhat better. The estimate of 31.2 million ducks represents a 14 percent drop from last year year. It is 22 percent lower than the 39.8 million found in 1999, the largest breeding population counted since 1994. The “total duck” breeding population counts since 1994 are shown in the following graph.

North American Breeding Ducks

1994 1995 1996 1997 1998 1999 2000 2001 2002

Year

Importantly, all individual species of ducks counted in the breeding-ground survey declined from last year. Hardest hit were pintails, down 46 percent from last year, shovelers, down 30 percent, and blue-winged teal, down 27 percent.

By species, it worked out this way.

The first percentage is the decline from last year and the second is the decline from each species’ 1994-2002 peak population.

What does all this mean for the upcoming hunting season. We can construct a fall-flight forecast equation to predict the fall flight where:

BPoP = Breeding Population Ss = Adult Summer Survival, assumed to be .82 AR = Age-ratio Jv = Juvenile gunning vulnerability, assumed to be 1.25

Our equation is:

Fall Flight = (BPoP x .82) (1 + [AR/1.25])

We will use seven of the 10 “species” counted in the breeding-ground survey – mallards, pintails, gadwall, widgeon, green-wings, blue-wings and scaup – to calculate our fall-flight index. The seven account on average for 85 percent of the total breeding population. Excluded are shovelers, redheads and canvasbacks. The age-ratio for the 2002 fall-flight is estimated from past age-ratios under similar pothole conditions.

When we do the math, we find this autumn’s fall-flight will decline to 33.8 million ducks, a 28 percent decrease from last year and 47 percent below the 1997 peak.

A comparison fall-flight chart for the years 1994-2001, and the predicted flight for 2002, is shown below:

Fall-Flight Forecast

1994 1995 1996 1997 1998 1999 2000 2001 2002

Year

Thus, we find that fewer ducks this spring will produce below average numbers of young. The fall-flight will be thin. This suggests the need for very conservative hunting regulations to protect our breeding flocks.