Dry habitat conditions may dampen duck production

Many Canadians enjoyed a warmer and drier than usual winter, but how will it affect waterfowl habitats this spring?

Warmer than usual winter weather may create some challenges for nesting ducks. © DUC

Most years, Simcoe County is a snow-lover’s paradise. Its picturesque hills and trails attract outdoor enthusiasts from across the country. But this past winter, when people should have been readying to hit the slopes, they were rigging their sails.

“On the last day of February, I saw someone wind surfing on Hamilton Harbour. Last winter, there would have been icebreakers out there,” says David McLachlin, a DUC biologist in Ontario.

McLachlin’s observations, though unusual, are not unique.

In many areas across the country, DUC staff reported warmer and drier conditions this past winter than in previous years. According to meteorologists, the weather can be chalked up to the El Nino Southern Oscillation (ENSO). El Nino, the warm phase of ENSO, is a climate pattern that occurs irregularly every two to seven years, and traditionally causes milder winters in Canada.

And while warmer than usual winter weather may have been ideal for surfers and sailors, it may ruffle a few feathers among the waterfowl population this spring.

According to David Howerter, DUC’s director of conservation science, spring habitat conditions will vary across the country.

In areas like the boreal forest, where there are big, deep wetlands that rarely go dry, habitat conditions will remain relatively stable. “They may have less or more water in them, but the ponds are holding water regardless,” says Howerter.

However, if dry conditions persist in the Prairies, wetlands will likely become competitive grounds for waterfowl.

“Four of the last five years we had record numbers of breeding ducks in North America. So there are lots of birds out there. And they will return and likely find much drier conditions than when they left,” says Howerter. “What that can set up is what ecologists call a density-dependent response,” he adds.

Density dependence can occur when species compete for a limited resource. In the case of a dry year, waterfowl will challenge one another for productive wetlands. “Younger birds, and the birds in poorer physical conditions can get pushed to the lower quality habitats,” says Howerter.

He notes that while such conditions may not be ideal for waterfowl this year, over the long term, dry periods create more dynamic wetlands.

“One of the reasons why the Prairies are the most productive areas in the world for ducks is because they get super wet and they get super dry. When water returns to the Prairies after a period of drought, the conditions are set for a few years of tremendous production.”

Early birds: reports from field staff

This report is compiled by Ducks Unlimited Canada field staff, who describe environmental conditions relative to waterfowl. Their anecdotal observations are not based on scientific surveys, nor are they intended to describe hunting conditions. The following is a summary of conditions, as of late March 2016.

British Columbia: Flooded south coast wetlands and fields created extensive habitat for wintering and migrating waterfowl, including a large pulse of northern pintails and mallards in mid-March. Spring runoff and migration started early in the Interior and Peace regions, with some swans and early-nesting ducks arriving in early March.

Western Boreal Forest: It was a warm winter, with temperatures climbing over 5 C higher than normal. Winter precipitation was average, except in the Yukon and in parts of Alberta, which were drier. Geese and swans made an appearance up to two weeks sooner than usual.

Alberta: Below-average spring wetland conditions are expected in the southern prairie, western boreal transition zone and most of the Aspen Parkland and Peace Parkland. Canada geese were first observed in the Aspen Parkland in late February, followed by mallards, northern pintails and American wigeons the third week of March.

Saskatchewan: After a relatively dry winter, southern prairie areas will have very little runoff. However, the parkland is faring better and will benefit from carry-over from 2015. The first ducks and geese arrived in mid-March but had to contend with several snow storms later in the month, especially in central portions of the province.

Manitoba: Winter precipitation in southwest breeding areas was well below normal, which led to little or no snowpack and minimal spring runoff.  Significant precipitation will be needed to maintain and improve wetland conditions.  Canada geese were observed in late February, and mallards and northern pintails appeared by mid-March.

Ontario: Despite significantly warm winter temperatures that reduced the snowpack, abundant winter rainfall ensured that wetlands were filled.  Many mallards, sea ducks and divers overwintered in the province, likely due to the lack of ice cover on the lower Great Lakes. Migrants arrived early, with one pair of Canada geese observed on February 1 near the city of Barrie.

Quebec: Winter precipitation was generally below normal — with 25 per cent less snowfall than usual — but some areas retained moisture and the St. Lawrence River water level remained high. Spring migration started in early March, with observations including 125,000 greater snow geese in the Lac St. Pierre region.

Atlantic Canada: Low snow accumulation and mild temperatures resulted in early open-water conditions for waterfowl. Given last fall’s high water levels, coupled with the early arrival of spring, wetlands should be favourable for nesting waterfowl.  Mallards, American black ducks, ring-necked ducks and common goldeneyes arrived in mid-to-late March.