Volume 90, Issue 75

Thursday, February 06, 1997



Duck, duck, Canada goose

Re: Geese go away... Jan. 21

To the editor:

This letter is in response to Veer Gidwaney's article, "Geese go away... It's winter, eh!" Although it was written in good humour, it contains many misconceptions about waterfowl.

Having made our careers studying avian ecology we felt it our duty to inform your readers about the Giant Canada Goose. We are sure many people believe Giant Canada Geese (not "Canadian" Geese) spending the winter on the Thames River near campus is a "freak occurrence of nature." However, this phenomenon is not at all uncommon. In fact, many species of birds are non-migratory and spend their winter months in northern latitudes.

"Frigid" may be too strong an adjective for winters in southern Ontario, since they are relatively short and mild compared to the rest of Canada. The relatively mild temperatures keep some aquatic areas (e.g. the Thames River) ice-free the entire winter allowing Canada Geese, Mallards, Black Ducks and other waterfowl to remain here comfortably year round.

Out of 11 sub-species of Canada Geese, only the Giant is non-migratory. These geese are well adapted for wintering at northern latitudes because their large body size allows them to conserve energy and store fat which helps them survive the few "frigid" weeks that they do endure. Also, they sport a rather cozy natural down jacket that provides both warmth and a natural waterproofing – better than anything Mountain Equipment Co-op can offer! Another adaptation for surviving cold weather is a counter-current heat exchange system in the arteries of their legs and feet. This allows just enough warm blood to circulate to their webbed feet to prevent tissue damage while consequently conserving heat and preventing webbed feet from freezing to the ice.

Being so well adapted for northern living it would be unwise for them to migrate south for the winter. First, it is energetically expensive for such a large bird (six kg) to fly south. Also, it is wise for them not to migrate because they know where to roost at night and where to feed during the day, at the same time avoiding avian and mammalian predators, including human hunters. Southern Ontario is well suited for their lifestyle. There are areas within the city in which to drink and rest.

For such a "dumb" species, the Giants are doing extremely well! For example, since their reintroduction to southern Ontario during the 1960s their population has increased exponentially. The current population estimate is about a quarter of a million birds, perhaps the highest density in North America. The negative aspects associated with too many geese such as increased crop damage and goose droppings in golf courses and city parks will require the human population to demand a reduction in the population size. If these geese in London continue to increase they will become more of a nuisance and will indeed die a "dumb death" due to a need to control their population size. So Mr. Gidwaney as you can see the "tragic" fate the Giant Canada Geese of the Thames meet will not result from frigid air freezing their feet to the ice or from starvation. Rather, it will undoubtedly result from their ignorance of proper birth control methods.

Avian Energetics Laboratory, department of zoology:

Shannon S. Badzinski, M.Sc. candidate zoology

Debbie Giesbrecht,

honours B.Sc. ecology and evolution, 1996

Michael R. J. Hill, PhD candidate zoology

Allan Hanson, PhD candidate zoology

To Contact The Letters Department: gazoped@julian.uwo.ca

Copyright The Gazette 1997