Just What Happened to All Those Ducks?
Dr. David Vaught 04.02.13
The 2012-2013 waterfowl season might have some wondering–what happened to the all the ducks in portions of the Mississippi Flyway? Breeding predictions had many thinking we might have incredible success with a 15 percent increase in mallards, 10 percent increase in gadwall, 20 percent increase in green-winged teal and a 21 percent jump in scaup. I know from a very robust personal sampling across many hunting days along the Missouri River in mid-Missouri those ducks just did not show up. Some publicly managed areas in Missouri along the river had populations of ducks at almost 200,000, but reports were confounding for non-public ground hunters with 750,000 mallards holding in South Dakota as late as mid-December. Had it not been for winter storm Bruce, hunter frustration might have been even higher.
So what might have happened? Borrowing from Dale Humburg, Ducks Unlimited’s chief scientist, some likely had great seasons and some did not. It was a year of extreme deviation from the mean. A look at several possibilities is worth exploring, including the summer drought, farming, and a most influential La Niña.
By June 2012, it was apparent the drought in the Midwest was going to become newsworthy, not to mention the warmest year on record in Missouri and other states since 1895. It was in fact in the top three droughts on record for Missouri and prevails into the new year. Following extensive flooding in 2011 along the Missouri River, 2012 presented a drastic change. Moist soil habitat actually in many locations recovered very well after spending almost four months under water in 2011, but farm crops suffered. Corn was planted in the most acres since 1937, yet thousands of acres of prime river bottom land had poor crop yields and as a result many farmers began an early assault on corn converting it to silage to save a total loss. A few farmers held out optimistically for bushels of $8 corn, but the early corn harvest created a chain of events that soon left fields ready to spring plant. By late November in many areas, anhydrous ammonia incorporation had farm suppliers scrambling to meet the fertilizer demand that would normally come in April or May the following year. As the drought continued, the planting of winter wheat also declined or was delayed with little or no rain to begin the germination process.
The bottom line for the fall of 2012 was a lack of food or water to stop or hold birds along many areas on the Missouri River. Public areas managed for food and with heavy pumping of water could and did draw and hold birds. However, even some of those public areas adjacent to the Missouri River had pumping limitations as the river dropped to precarious levels at all gauging stations below Gavins Point Dam.
Secondarily, the drought took a while to show itself in ponds and lakes, but by the early September teal season, the water levels were making history. Missouri, in most areas, saw record low precipitation with Kansas City receiving only 20.94 inches in 2012 when normally nearly 40 inches would fall. This year and 1953 were 125-year records for low precipitation, translating to low river levels and little or no rain to refill lakes and ponds. Pot holes and shallow ponds were dry by mid-October. As someone that takes an interest in waterfowl and water resources, I continue to be amazed at the number of dry ponds. But even with water, many experienced few birds during the fall migration.
It is becoming clearer that drought may have an impact on bird migration. In 2011, bird counts in Texas revealed Whooping Cranes arrived to overwinter on the coast, but soon departed due to a lack of food. Other species that do not tend to migrate as far south as Texas migrated extreme distances in search of food outside their normal migration pattern. Even more evidence is the Sandhill Crane never reaching the warmer climates of the coast, but rather stopping in mid-prairie states.
Global weather, perhaps above all other influences, was a huge player this fall (and last year) with a dominant La Niña holding on to North American weather patterns for an unprecedented third year. La Niña is the colder baby sister of El Niño. Cold ocean La Niña temperatures in the equatorial Pacific have a significant impact especially during the winter months on the continental United States. Northeastern states are warmer and southwestern and southeastern states are cooler. This long lasting La Niña is well beyond the normal one- and two-year occurrence. The influences on drought, temperature, and duck migration are arguably noticeable and this is especially true in the Midwest, where La Niña and El Niño tend to intersect. More to the point, the predictability of weather and associated migrations may be the most difficult in the Midwest to understand due to Pacific temperatures, but likely correlate with migration patterns. What we do recognize is that of the six La Niña years between 1964 and 1995, three of them have corresponded to lower-than-normal duck harvests.
While a weak El Niño tried to form in the early fall, it was regulated by a cold neutral La Niña. Weak El Niños provide a cooler, wetter fall. Early on the jet stream was predicted to dip in the Central and Pacific flyways, but rise over the Midwest Mississippi Flyway and create a dry, warm weather pattern with few fronts capable of pushing birds south. Snow failed to materialize due to the warm flow of air and generally it was late in December before snow cover closed off feeding grounds in northern states. The warm weather held the freezing to a minimum as well, so birds had food and water but little in the way of weather pressure to move south from northern states.
One can understand the frustration with predicted high numbers of ducks and for some a dismal hunting harvest. Drought, farming practices, food shortages, and weather played a critical role in the fall Mississippi Flyway 2012 migration. Keep an eye out in 2013 as the La Niña hopefully begins to dissipate and a warmer El Niño moves in to shift the jet stream east and provide more normal rainfall, more cold fronts, a staggered crop harvest, and a better duck migration.
