MIRROR MIGRATION

Eastern European Diving Duck Winter Distribution
Eastern European Mallard Winter Distribution
Goldeneye - Photo by Erni, Shutterstock
Barnacle geese were rarely observed in Sweden during the month of January until about 2001 but warmer winters have greatly increased their winter distribution in the country. -- Photo by Alexander Erdbeer , Shutterstock
goosander - Photo by Nick Kashenko , Shutterstock
tufted duck - Photo by Paul Broadbent , Shutterstock

Just Like In North America, Waterfowl Winter Distribution In Europe Trending Further North

story by Larry Reynolds, LDWF Waterfowl Program Manager

 

As we consider the many factors likely affecting the winter distribution and associated hunting opportunity for ducks and geese in Louisiana, it is important to recognize what is happening elsewhere in the Northern Hemisphere. Are ducks and geese wintering further north on other continents as well?

 

The political landscape and flyways across the Atlantic Ocean in Europe are a little different than in North America. Dozens of independent countries share the waterfowl resource and flyways predominantly go in a northeast to southwest direction with major breeding areas in Sweden, Finland and Russia feeding a migration to Spain, France, the United Kingdom and Ireland. Ducks and geese are popular with European hunters, and an estimated 5.5 million ducks were reported harvested in 24 countries in 2016.

 

However, unlike in North America, there is very little international coordination. Hunting regulations are set by each individual country, vary widely and are not cumulatively linked to the status of waterfowl populations. Consequently, there is a lot of concern about changes in winter distribution as they affect hunting mortality, survival and conservation.

 

Monitoring of waterfowl populations has traditionally been done through a variety of winter surveys. The coordinated International Waterbird Census was initiated in 1967 and now covers virtually all European countries, east to Russia and south through Africa. Along with dedicated winter waterfowl surveys in several other countries providing data for the last 30 years, researchers have described changes in winter distributions of a number of duck and goose species.

 

Mallards are as important to hunters in Europe as they are here and winter populations of mallards have declined in the United Kingdom since 1990 and in the Netherlands since 2000. At the same time, winter populations have increased further north and east in Sweden, Finland, Latvia and Estonia. Since 1995 counts in Sweden have increased more than 4 percent per year.

 

Data from banding, or ringing as they call it in Europe, also showed a northeast shift in winter mallard distribution. The recovery distribution of mallards banded in 2002-2008 shifted substantially to the northeast compared to that from mallards banded in 1964-1982. Bands also were recovered at a much lower rate (4.7 percent versus 13.3 percent) during the later period and survival rates were significantly higher.

 

Researchers speculated that could arise from milder winter conditions in recent decades and/or a change in winter distribution from areas with high hunting activity to those with less.

 

Winter counts have shown shifts in winter distribution for other ducks as well. European wigeon have increased in the northeastern portion of their winter range, which includes Norway, Sweden, Denmark and Germany, but decreased in the southwest portion, Spain and Ireland. From 1980 to 2010, three species of diving ducks, tufted duck, goldeneye and goosander, increased in Finland and Sweden but declined in France, Ireland and the Netherlands while the overall population remained constant.

 

Some species of geese show similar shifts in distribution. European white-fronted geese, almost identical to the specklebellies so highly valued by Louisiana hunters, winter primarily in the United Kingdom, Netherlands and Belgium. But from 1977 to 2013 winter counts in Sweden have increased tenfold while the overall population has remained stable.

 

Similarly, Barnacle geese were seldom seen in Sweden in January until around 2001 but counts have increased to nearly 8,000 by 2010. Wintering Greylag goose counts have increased from 120,000 to 610,000 across their winter range but the annual rates of increase from 1987-2009 were about 35 percent in Sweden and Denmark at the northern edge of their winter range compared to only 3 percent in Spain at the southern edge.

 

Climate change is considered the primary factor driving changes in winter distribution of European waterfowl. Temperatures in early winter at the northeast part of wintering areas have increased 3.6 to 7.2 degrees Fahrenheit since 1980.

 

What that means is fewer freezing days, more open water, delays in fall migration and increases in birds wintering further north. A study from 2019 reported mallards wintering in Moscow increased from 7,500 in the early 2000s to about 30,000 in 2015 owing to milder winters resulting in a freezing season that declined from 132 days to only 104.5 days during the study period, representing four weeks of improved habitat conditions for wintering waterfowl.

 

However, researchers are quick to point out that not all species of waterfowl are responding the same and habitat changes have also occurred. Changes in land-use and agricultural practices combined with milder winters have increased food available for migrating geese in Europe allowing them to winter further north. That sounds a lot like what is occurring in North America.

 

Recent Posts