Canada Geese are one of the larger members of the waterfowl family, weighing in at about 6.5 kg on average, compared to a Mallard at 1 to 1.3 kg. Only swans are bigger. Geese mate for life, and are found all over North America, breeding mostly in Canada (and Alaska), and wintering in southern Canada and down into the United States. Some populations are resident year-round.
In winter, we have very few geese in the Sanctuary, as they favour other areas of the Lower Mainland where they can find their favoured food, short lawn grass, to browse. You are more likely to find them in MetroVancouver parks and golf courses, or in rural farm fields that have winter grass cover growing in them. In spring, though, they seek out landscapes that have low nest sites overlooking water, and the Sanctuary has lots of shorelines like this so a few hundred move into our pond system. About half of these are first year birds, not sexually mature enough to nest yet, but they pair up. The remainder are usually adult pairs seeking territories, and there can be sometimes a month of "goose disputes" in a couple of key areas of our trail systems as about 20 pairs sort out things, as they tend to nest a little too close to one another.
Our visitors are sometimes a bit afraid of these birds during this spring period, as these are weighty muscular birds, and are aggressive towards any other geese and humans that trespass into their territories or threaten their mates or nest. Sometimes visitors do not reallize they are very close to a pair's nest, then suddenly there are two geese hissing at them, one utters some low honks as a threat, then charges. Forgive them, please. This is their natural behavior, whether in the wilds of the Yukon, in a manicured city park or in a bird sanctuary where perhaps a few too many of them are nesting too close together. In the city, birds that are used to people might even nest in a planter on a fifth floor apartment balcony but only if the humans are trustworthy and are careful not to intrude. They generally do not fear humans or even bears in the wild if it comes to defending a nest.
Pairs can lay anywhere from 2 to 8 eggs, and these need 25 to 28 days of incubation before they hatch The goose does not settle to incubate until the entire clutch has been laid. Initially the nests just look like a flattened pile of grass, as she covers the eggs when she leaves the nest for brief foraging. When she is ready to incubate, though, the nest is lined with down pulled from her underside, and this makes an insulating blanket to keep all of the eggs warm.
In the Sanctuary, we see the hatch of young goslings usually around Mother's Day in early May. These goslings are yellow and downy and spend a lot of the day sheltering under their parents if it is hot, cold or raining, as they are not weatherproof until they grow some smooth overlapping feathers. Male and female of the pair share parenting duties, and it is common to see a pair guarding the whole family as they walk the trails. The main diet of goslings when young is short juicy grass and aquatic invertebrates and algae.
Goslings take about 3 months from hatching time to become fully feathered and flying. During this period, their parents and other adult Canada Geese moult their old worn flight feathers, so nearly all geese in the Sanctuary from late June onwards are in various stages of flightlessness. There are feathers drifting all over the Sanctuary then, and the birds begin to grow replacement feathers. By August, most adults and this year's young have new flight feathers. There are lots of "training flights" for the new geese in our parking lot once all of the visitors have left.
Our local born geese are soon joined by sometimes hundreds of other Canada Geese from up the valley that were also flightless over the summer and floated downstream on the channels to the Fraser River to reach the Sanctuary where the river meets the sea. As soon as all of these birds can can fly, the Delta area is full of geese in crops, geese in ponds, and geese offshore. In the fall, there is a goose hunting season in Delta and the wiser of the birds then head out to find the nice parks and golf courses in the city to forage on the lawn grass and keep safe.
We have posted photos of this goose species and other Sanctuary birds on Flickr.