What’s all that Noise About?
by Chris Holland
Canada Geese, Branta canadensis
- ORDER: Anseriformes
- FAMILY: Anatidae
So, what’s all the noise about ! Our dear friends the Canada Goose is feeling the warmer temperatures and romance comes to mind (even in animals). During spring, pairs break out from flocks and begin defending territories. Spacing of these pairs is variable and depends on availability of nest sites and population density; where population is large, even after a great many fights birds may end up nesting in view of one another, and some populations are semi-colonial. They mate for life with very low “divorce rates,” and pairs remain together throughout the year. Geese mate “assortatively,” larger birds choosing larger mates and smaller ones choosing smaller mates; in a given pair, the male is usually larger than the female. Most Canada Geese do not breed until their fourth year; less than 10 percent breed as yearlings, and most pair bonds are unstable until birds are at least two or three years old. Extra-pair copulations have been documented.
Canada Goose threat displays may involve head pumping, bill opened with tongue raised, hissing, honking, and vibrating neck feathers. When an intruding goose doesn’t retreat, geese may grab each other by breast or throat and hit each other with their wings. Fighting may result in injuries. During summer, and increasingly at other times of year, Canada Geese are fairly easy to see, swimming in open water, resting near shore, or grazing on lawns or farm fields. They are often heard flying above, by day or night; if you study their honks you may notice the difference by sound when other species of geese or swans are flying.
- At least 11 subspecies of Canada Goose have been recognized, although only a couple are distinctive. In general, the geese get smaller as you move northward, and darker as you go westward. The four smallest forms are now considered a different species: the Cackling Goose.
- Some migratory populations of the Canada Goose are not going as far south in the winter as they used to. This northward range shift has been attributed to changes in farm practices that makes waste grain more available in fall and winter, as well as changes in hunting pressure and changes in weather.
- Individual Canada Geese from most populations make annual northward migrations after breeding. Nonbreeding geese, or those that lost nests early in the breeding season, may move anywhere from several kilometers to more than 1500 km northward. There they take advantage of vegetation in an earlier state of growth to fuel their molt. Even members of “resident” populations, which do not migrate southward in winter, will move north in late summer to molt.
- The “giant” Canada Goose, Branta canadensis maxima, bred from central Manitoba to Kentucky but was nearly driven extinct in the early 1900s. Programs to reestablish the subspecies to its original range were in many places so successful that the geese have become a nuisance in many urban and suburban areas.
- In a pattern biologists call “assortative mating,” birds of both sexes tend to choose mates of a similar size.
- The oldest known wild Canada Goose was a female, and at least 33 years, 3 months old when she was shot in Ontario in 2001. She had been banded in Ohio in 1969.
Chris Holland is a Naturist and teaches at the Audubon Society and Environmental Center, Newport Beach. He also does bird walks upon request at the Wildlife Sanctury in Irvine. A number of birds around the lake can be identified by going to the Lake Forest Community Association Village News website. www.lfca1.com