“A Year of Birding in
Bloedel” is a column that runs every Friday in the Bainbridge
Islander. The project is planned to continue in 52 parts through
2014 to help readers find and identify birds in the island’s garden
sanctuary. Beginning with this entry on the Canada geese,
each column will also be published here on the Bainbridge
Conversation blog each Friday.
The author, Ted Anderson, is a retired professor of biology,
having taught at McKendree University (Ill.) for 32 years and for
the University of Michigan’s summer biological station for 20
years, where he frequently taught the biology of birds.
Anderson is also the author of “Biology of the Ubiquitous
House Sparrow, from Genes to Populations” (2006), and “The Life of
David Lack, Father of Evolutionary Ecology” (2013). Ted
and his wife Carol have been members of Bloedel Reserve for 7
years. They live in Kingston.
No one requires an introduction to the Canada goose (Branta
canadensis), a common year-round resident of the Pacific
Northwest. Anyone who has visited parks around our area lakes or
Puget Sound is familiar with the unappreciated “calling cards”
these geese leave on lawns and paths close to water. Grazing
on grass and other terrestrial plants is their primary means of
foraging, although they can also be seen tipping up in shallow
water like dabbling ducks to feed on aquatic vegetation. At
Bloedel they are frequently found grazing in grassy areas near the
Bird Marsh, or on the lawns near the Visitor’s Center.
The Canada goose is common throughout much of North America,
breeding as far north as Alaska and the Yukon in Canada, and
wintering wherever there is permanent open water. Their spring
migration in southern Wisconsin inspired Aldo Leopold to proclaim
in A Sand County Almanac, “One swallow does not make a
summer, but one skein of geese cleaving the murk of a March thaw,
is the spring.”
Biologists have long observed that many widespread species vary
in size and/or coloration across their broad geographical
range. One way in which they have formally recognized these
differences is by the naming of subspecies, within-species groups
that differ significantly in size and/or coloration. Most
subspecific differences are so subtle that they are recognizable
only to specialists. Until very recently, however, scientists
considered some of the most northern breeding populations, in which
adults are only about half the size of our local Canada Geese, to
be easily identified subspecies of the Canada goose. These
populations are now recognized as a separate species, named the
Cackling goose. A wintering Cackling goose has joined the
resident Canada geese at Bloedel this winter. Look closely at
the foraging flocks of geese for an individual that is only half
the size of its compatriots.
The Canada Goose has been successfully introduced into England,
where many consider it a pest. In fact, they maintain the
Canada goose and the gray squirrel (also introduced from the United
States) represent our retaliation for their export of the house
sparrow and European starling to the United States.
