By Matt Young
This year’s Waterfowl Breeding Population and Habitat Survey offered mixed results for hunters and others who appreciate North America’s migratory birds. According to the U.S. Fish and Wildlife Service (USFWS), total populations of breeding ducks were estimated at 41.2 million birds in the traditional survey area, a decrease of 13 percent from last year’s estimate of 47.3 million. However, total duck numbers remained 17 percent above the 1955−2017 average. In addition, populations of the most abundant duck species were above their long-term averages, except for northern pintails and scaup (see chart).
Although large numbers of ducks and geese returned to the breeding grounds this spring, wetland conditions were generally less favorable for waterfowl production than in recent years. May ponds—the unit of measure for wetland abundance on the prairies—were down 14 percent, from just under 6.1 million ponds in 2017 to slightly more than 5.2 million ponds this spring. The total May pond count, unlike the estimate of breeding ducks, was near the long-term average.
“The dip in the population for prairie-breeding puddle ducks is not unexpected and by no means unprecedented given that conditions on the prairies this spring were drier than last year,” said DU Chief Scientist Dr. Tom Moorman. “As a result, 2018 populations dropped accordingly. This year’s breeding population decline is a reminder of the need to sustain the capacity of breeding habitats, particularly on the prairies as we go through natural variations in wetland conditions. Waterfowl populations are adapted well to short-term swings in habitat conditions, but we must continue to guard against the long-term loss of prairie breeding habitat.”
Annual changes in duck and goose numbers have important implications for waterfowlers but do not necessarily influence individual hunting success. Weather and local habitat conditions often affect the fortunes of waterfowlers more than the size of the fall flight, especially in migration and wintering areas. With that in mind, the following is an overview of waterfowl populations in each flyway, based on reports from the USFWS and DU biologists in the field.
The majority of Pacific Flyway waterfowl are raised on the prairies of the United States and Canada as well as in northwestern Canada, Alaska, and other western states. In southern Alberta, spring arrived quickly after a wintry start to April. The rapid snowmelt caused some localized flooding and recharged many wetland basins. Following a delayed start, waterfowl breeding efforts were in full swing by mid-May. Total breeding ducks in the region were down 14 percent from the 2017 estimate but remained 28 percent above the long-term average.
“Summer was warmer and drier than average across southern and central Alberta, but carryover water from the spring runoff and localized rainfall helped maintain semipermanent wetland habitats,” reports DU Canada biologist Ian McFarlane. “Although waterfowl breeding efforts were delayed by cool spring weather, good numbers of broods were observed in many areas.”
Farther north, in the Western Boreal Forest of northern Alberta, northeastern British Columbia, and the Northwest Territories, the abundance of breeding ducks was down 13 percent from last year’s estimate but remained 33 percent above the long-term average. In Alaska and the Yukon, breeding ducks decreased 15 percent and were 9 percent below the long-term average.
DU Canada biologist Jamie Kenyon reports that wetland conditions were generally favorable for breeding waterfowl across much of the Western Boreal Forest. “After a dry spring, it was very wet in the northern prairie provinces and southern territories, with up to double the average summer precipitation. The Northwest Territories had record-breaking rainfall in June, resulting in full ponds and fast-flowing rivers. Ponds in the Yukon are full too, and many broods of a variety of species have been observed,” Kenyon says.
In the western United States, wetland conditions were variable as some areas have improved while others continue to suffer drought conditions. In California, total ducks were up 39 percent compared to the 2017 estimate and were near the long-term average. In Oregon and Washington, duck populations were up 23 percent and 16 percent, respectively, and were above the long-term average in both states.
According to the USFWS, spring weather and habitat conditions were mixed for Pacific Flyway goose populations. An early spring thaw in the Yukon-Kuskokwim Delta and southwest Alaska provided favorable conditions for breeding cackling geese, white-fronted geese, emperor geese, and Pacific brant, while a delayed spring thaw in northern Alaska and the western Canadian Arctic may have negatively impacted breeding success among lesser snow geese, Ross’s geese, and other species in those areas.
The Central Flyway receives most of its waterfowl from the prairies as well as from the Western Boreal Forest and Arctic, with large numbers of ducks coming from Saskatchewan, eastern Alberta, North and South Dakota, and eastern Montana. In southern Saskatchewan, a slow spring thaw and average to below-average runoff limited seasonal wetland habitat for breeding waterfowl in many areas. In addition, the arrival of ducks and geese was delayed by cool weather. By early May, however, waterfowl breeding efforts were well under way for early nesters such as mallards and northern pintails.
Total duck numbers in southern Saskatchewan were down 30 percent from last year’s estimate but remained 6 percent above the long-term average. “Summer rainfall across this province was average to above average, except in the southwest, where precipitation was well below average,” reports DU Canada biologist John Trevor. “In areas that received sufficient rainfall, semipermanent wetlands provided good habitat for breeding waterfowl. Nesting efforts were delayed by the late spring, however, and duck broods didn’t begin appearing until early July.”
In the north-central United States, returning waterfowl found variable habitat conditions this spring across much of the region. In the eastern Dakotas, breeding duck numbers were similar to last year’s estimates and remained 33 percent above the long-term average. In the western Dakotas and Montana, duck numbers were also almost unchanged from the 2017 estimate and remained 29 percent above the long-term average.
“Habitat conditions across the Dakotas and northeastern Montana have improved, thanks to ample late spring and summer rains in many areas,” reports Dr. Johann Walker, director of conservation programs in DU’s Great Plains Region. “Given this year’s waterfowl breeding population estimates and habitat conditions, the region’s contribution to the fall flight will likely be near the long-term average.”
Central Flyway goose populations remain high, but a late spring on key breeding areas may have reduced production of many species. Average or below-average breeding success was expected for prairie-breeding Canada geese as well as northern-nesting lesser Canada geese, snow geese, Ross’s geese, and white-fronted geese. As a result, this year’s fall flight may include a lower proportion of juvenile geese than in recent years.
The majority of Mississippi Flyway waterfowl are raised on the prairies of the United States and Canada, as well as in the Western Boreal Forest, southern and central Ontario, and the Great Lakes states. In southern Manitoba, below-average winter snowfall and spring precipitation left many wetland basins dry or with low water levels. Total breeding ducks in this survey area were down 5 percent this spring but remained 7 percent above the long-term average.
DU Canada biologist Lena Vanden Elsen reports that cool weather delayed waterfowl breeding efforts in southern Manitoba this spring. “As in the other prairie provinces, brood observations in Manitoba were well below average in June and spiked in early to mid-July. Despite dry summer weather, many semipermanent wetlands retained enough water to provide good habitat for waterfowl broods,” Vanden Elsen says.
The waterfowl production outlook was mixed in neighboring Ontario, which is an important breeding ground for the Mississippi and Atlantic Flyways. “Summer precipitation and temperatures were variable across the province, with dry weather and average temperatures in the south and average precipitation and above-average temperatures in the north,” reports DU Canada biologist David McLachlin. “Nesting Canada geese appear to have been impacted by cool spring weather, while mallards and other ducks have had a more typical breeding effort.”
Ducks and geese raised in the Great Lakes states make an important contribution to waterfowl populations locally and throughout the Mississippi and Atlantic Flyways. Spring arrived late in this region, which delayed waterfowl breeding efforts despite generally favorable wetland conditions. In Minnesota, total duck numbers increased 9 percent and were 12 percent above the long-term average. The Wisconsin duck population estimate was similar to the last year’s and the long-term average, while in Michigan, duck numbers declined 34 percent and were 28 percent below the long-term average.
The outlook for Mississippi Flyway goose populations is mixed. While numbers of Arctic-nesting geese remain near record highs, weather and habitat conditions on northern breeding areas likely resulted in average to below-average production of lesser snow, Ross’s, and white-fronted geese. The same can be said for migratory populations of large Canada geese, which appear to have had fair to poor production in 2018.
The majority of Atlantic Flyway waterfowl are raised in the northeastern United States and eastern Canada, although this flyway also receives large numbers of dabbling ducks from the Great Lakes states and divers from the prairies. In the eastern survey area (eastern Ontario, Quebec, the Maritimes Provinces, Maine, and northern New York), breeding populations of mallards, American black ducks, and common goldeneyes were similar to last year’s estimates but remained below their respective long-term (1990−2017) averages. Breeding populations of American green-winged teal, ring-necked ducks, and mergansers were similar both to last year’s estimates and their long-term averages. In the northeastern United States, total duck numbers were similar to last year’s estimate and the long-term average. However, the abundance of breeding mallards remained 32 percent below the long-term average in this region.
DU Canada biologist Nic McLellan reports that weather and habitat conditions in Atlantic Canada were mixed for breeding waterfowl this year. “This region received average to above-average precipitation this summer, but brood production appears to have been below average or late, likely due to cold spring weather and flooding, which persisted well into June,” McLellan says.
An unusually late spring thaw in the eastern Arctic also likely impacted breeding success among Atlantic Flyway goose populations. According to USFWS surveys, below-average production was expected for Atlantic Population Canada geese, greater snow geese, and Atlantic brant.
The Waterfowl Breeding Population and Habitat Survey provides the scientific basis for many important waterfowl management decisions, including the drafting of annual hunting regulations. Individual states set their hunting regulations within federal frameworks, which prescribe season lengths and dates and daily bag and possession limits for each flyway. The USFWS and flyway councils will use this year’s spring breeding ground survey data to recommend hunting regulations frameworks for the 2019−2020 waterfowl seasons.