Canada geese, an invasive species soon to be culled

Once a protected species, Canada geese (Branta canadensis) may soon become a target for hunters. There are certainly so many of them in France that they are beginning to pose a threat to wetland biodiversity. On 6 September, the day before the shooting season opened in France, the National Hunters Federation (FNC) repeated its determination to have the geese put back on the list of waterfowl that can be hunted. But is this the right answer?

The Canada goose is the largest goose found in Europe. It was introduced to Britain in the 17th century, then adopted as a game bird on the continent during the last century. In the wild they live 10 to 25 years and are prolific breeders. They are now resident in western Europe and, for reasons that remain obscure, their numbers have started increasing very fast. They are now on a list of 100 invasive species posing a serious threat to biodiversity in Europe.

There were only several hundred Canada geese in France at the end of the 1990s. Now there are more than 5,000 spread over at least 58 départements, with half in the Paris area.

"Unlike other wild geese, the Canada goose is quite happy in the suburbs, in parks, on lakes and in marinas," says ornithologist Philippe Dubois, who is coordinating a national survey of invasive alien species for France's League for the Protection of Birds (LPO). "Their droppings really make a mess on lawns and leisure areas, and in swimming pools." In 2009 the health risk caused by this pollution led to the temporary closure of an outdoor leisure centre at Cergy-Pontoise, north-west of Paris.

If they settle in wilder spots, Canada geese pose other problems. "They have a strong sense of territory and will prevent other waterfowl from moving into quite a large area round their nest, so they may hinder reproduction by ducks, coots and other goose species," Dubois says. He reckons that if the present population dynamic continues, something will have to be done. This would involve a more radical response than the occasional measures taken recently by the National Agency for Hunting and Wildlife (ONCFS), sterilising eggs and culling birds on the orders of the local government representative.

In response to a government request for plans for a campaign, the ONCFS recommended a culling role for hunters. But Pierre Migot, its head, pointed out that many people don't want the geese to disappear and a goal needs to be set. So it remains to be seen what fate awaits the Canada goose in France.
Frédéric Jiguet, an ornithologist at the Muséum d'Histoire Naturelle in Paris, has a compromise. "Maybe they should resume hunting this invasive species," he says. "But in exchange we should take the greylag goose off the game list, at least from August to October." In 2010 there were only 150 pairs left in France.

This article orginally appeared in Le Monde

http://www.guardian.co.uk/environment/2011/sep/27/france-considers-canada-geese-cull?newsfeed=true