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Volume 38 Issue 20 • Sept 11 - 17, 2008
now in our 37th season

The Song of the Canada Geese

by Dr. Sarah D. Oktay
Managing Director UMass Boston Nantucket Field Station

A friend of mine told me once that they reminded her of old men laughing and that description has stuck with me for many, many years.  The honking cacophony often can be heard before a tell-tale v-shaped flock, or chevron, crosses the sky.  The sight of Canada geese (Branta canadensis) migrating is a definitive sign of fall’s approach and a reminder to slow down and enjoy the crisp, cool weather.  Now in some parts of the country, their presence lingers much longer and some Canada geese have become non-migratory.  Our lush golf courses with inviting ponds and waste grains scattered in fields after mechanical harvesting have made the bed and board too hard to resist.  Canada geese are on the road to becoming significant nuisance species in urban and rural areas.  But before we run them out on a rail, let’s find out a bit more about them.

Canada geese are monogamous, and they typically breed during their second year of life.  They will often stay with their soul mates for life.  Many people call them Canadian Geese, but that is not only inaccurate, but also a pet peeve of many ornithologists.  Canada Geese belong to the genus Branta in the Class Aves, Order Anseriformes, Family Anatidae, and Subfamily Anserinae. According to the Oxford English Dictionary, the first citation for a Canada Goose dates back to 1772.  Canada geese are the most widely distributed geese in North America.  They can be found all over North America all the way north up to the Arctic and from coast to coast down to the plain states and even down to the Gulf of Mexico in the case of some nonbreeding individuals.

There are 7 subspecies of Canada geese (Dusky, Vancouver, Lesser, Moffitt’s, Giant, Interior, and Sylantic) and recently the American Ornithologists' Union decided to split out a group of smaller geese previously lumped into the Canada Goose category into their own species called the Cackling Goose (Branta hutchinsii).  The body coloration, plumage, size and taxonomy are closely linked between the two and currently there are approximately 5 sub-species in the Cackling Goose category.  Canada Geese are distinguished from other geese by their black heads and long black necks with white "chinstrap." Canada Geese are very large water birds with light tan to cream colored breast feathers and a brownish back and white underside.  They stand around 30-44 inches tall and have a 50-65 inch wingspan and usually weigh anywhere from 4-18 pounds.  The largest subspecies is the Giant Canada Goose, with a wingspan of 6 feet and weighing up to 20 pounds.  Among North American waterfowl, only the swans are larger.

The different species have a variety of differing coloration from lighter to darker and will vary in size.  In general, the geese get smaller as you move northward, and darker as you go westward.  Extensive hunting and wetland destruction threatened some populations of Canada Geese in the 1900s.  In particular, the subspecies known as the giant Canada Goose was considered extinct until a few remnant populations were discovered in the early 1960s.  Improved game management practices and extensive re-introduction programs were begun to stabilize the subspecies and today it is doing fine.  Originally a North American bird, the Canada Goose has also been transplanted successfully to Britain and Scandinavia.  The geese were first introduced in Britain in the late 17th century as an addition to King James II's waterfowl collection in St. James's Park.  Canada Geese have also been introduced to New Zealand for hunting purposes.

Males (ganders) usually are slightly larger than the females and males are much more aggressive and will passionately protect the clutch of eggs that the female has deposited in a nest near the water.  Incubation takes 25 to 30 days and the goslings are led to water within a day after hatching. Males become much more tolerant of other geese after their kids are born and some geese will raise their young with other Canada Geese families in groups called crèches.  Goslings are yellow with some greenish-gray colorings on top of their heads and backs (and very cute).  As with the adult color pattern, there is some variation among the different subspecies.  Goslings of the darker subspecies have a brownish olive or blunt yellow coloring while those of the lighter subspecies are lighter and brighter in color.  These colors fade as the gosling grows into the adult color pattern.  All goslings have black or blue-gray bills and legs that become darker as they age.  The parents march the goslings around in a straight line with one parent at the front and one parent at the back.  One way to distinguish Moms from Dads is that the females have a different call.  The gander has a slower, low-pitched "honk" while the goose's voice is a much faster and higher-pitched "hink."  Mated pairs will greet each other by alternating their calls so rapidly that it seems like only one is talking.  A careful ear will be able to put each voice with its rightful owner, which is very helpful since the male and female look alike.  As I am sure most of you have experienced, when agitated, Canada geese will make a series of loud and rapid calls and flocks will sound off in a raucous chorus when they take off or land.  I particularly like their pontoon boat-like landings on water.

Canada Geese usually migrate south when the chicks are ready to fly in late summer and early fall.  They migrate back north as the weather warms. During the first year, families stay together and travels in large flocks as far south as Veracruz and Jalisco in south-central Mexico.  Scientists think that the reason these birds fly in the V-formation is due to what is known as the “drafting effect.”  Basically, this helps the birds to conserve their energy while flying long distances. The leader in the front splits the air current (and at the same time uses the most energy).  When he tires, he moves to the back then another goose takes over the lead spot.  Migrating birds usually follow the same path every year.  These paths are called routes or flyways.  The flyways used by the Canada Goose are: the Atlantic flyway (along the east coast of North America); the Mississippi flyway (named after the river); the Central flyway (along the Rocky Mountains); and the Pacific flyway (west of the Rockies).  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 make waste grain more available in fall and winter, as well as changes in hunting pressure and changes in weather.

In addition to using drafting while flying in a V or diagonal line, the migration formation may also help them communicate better.  Some scientists believe that Canada geese may use up to 13 different calls to vocalize information including warnings, greetings, and simply cause they are chatty.  When they migrate north in the spring, they fly at a slow pace, stopping along the way.  Because of this, they arrive at their spring breeding grounds in good physical shape.  Canada geese usually start migrating south when the ground begins to freeze in the fall and the goslings have fledged and then they fly much faster, sometimes covering as much as 1000 km in a day!

Canada Geese breed from eastern Labrador to western Alaska and as far south as 49°N in North America.  They can take advantage of a wide range of habitats in temperate to low-arctic regions, including flat, featureless tundra; boreal forest; prairies and parklands; high mountain meadows; and a variety of parks, and wildlife refuges.  They may nest individually or semi-colonially, preferring sites on small islands in tundra lakes and ponds, and on margins of lakes, ponds, and rivers.  Typically at the Field Station at least one pair will produce 4-9 chicks each year and they will hang out around the fresh water pond on the property.  Females incubate the eggs, choose the location for nesting, and even build the nest without males.  Males defend the territory, nest, and eggs from intruders, such as other geese.  Female Canada geese pick nesting sites that are isolated but have good visibility.  This allows them to readily see danger approaching.  The nesting area also must have open water with low banks so they can have access to water plants and places to get into or out of the water.  Swamps, marshes, meadows, lakes, and other such areas are among some of their favorite nesting spots.  Unguarded nests and eggs are targets for predators such as gulls, common ravens, American crows, skunks, domestic dogs, foxes, and many other animals (many of which are not found on Nantucket).  On ponds in Nantucket, large snapping turtles also are a primary predator of goslings.  Once they reach adulthood, Canada geese are rarely preyed on, but can be taken by coyotes, red foxes, gray wolves, snowy owls, great horned owls, golden eagles, and bald eagles. Canada geese have a lifespan that can reach 20-24 years and in captivity a few have even lived as long as 42 years.  On the breeding grounds, they forage primarily on grasses, sedges, and berries and in wintering areas they tend to switch to eating grasses and agricultural crops.  These geese also love to eat seaweed, eelgrass, submerged aquatic vegetation like sago pond weed, and bottom silt which is composed of decomposed plant matter.

Geese are becoming a large presence in many urban areas; the abundance of golf courses and suburban complexes with ponds provide a perfect nesting and feeding area with a minimum number of predators.  People often feed geese and nearby farms provide plenty of grain for short foraging trips. And the social nature of the birds can be greatly credited for increasing this phenomenon.   When one family of geese discovers that the city life is a good deal, they will remember and return the following year along with their youngsters and any flockmates they travel with.

Many water quality experts suspect fecal matter from geese to be a major contributor of phosphate and nitrate to the water bodies they inhabit.  A 10 pound goose can produce 4 pounds of phosphate and nitrate rich poop per day.  Phosphorus is a key ingredient in goose poop.  An interesting paper by Robert L.Unckless and Joseph C. Makarewicz (“The Impact of Nutrient Loading from Canada Geese (Branta canadensis) on Water Quality, a Mesocosm Approach”; July 2007, Hydrobiological) showed that the majority of nutrient input quickly settled to the sediment and did not stay in the water column, even when very high levels of goose poop were put into the water.  This material would not be provided to the water to feed algae blooms unless the sediment was overturned in a storm or through temperature change induced mixing.  This experiment does not mimic the introduction of poop washed into ponds from shore based “deposits” which may be next summer’s job for one of my high school interns (I can hear the applications coming in now). Another new area for research comes from studies which indicate that Canada Geese with access to agricultural areas can serve as reservoirs of antimicrobial-resistant bacteria such as Escherichia coli.

There are several ways to reduce geese and duck populations around ponds. One way is to not feed them! Also high grass and fences near ponds and even scarecrows can prevent then from building their nests.  High grass and vegetation provides cover for predators.  Some people even try plastic alligators and plastic coyotes to deter any resident geese; but like other birds, they will eventually figure out nothing is chasing them.  Some states have considered lengthening goose hunting seasons to reduce the population.  It is important to identify the prevailing species as some are much more common than others.  Poisons applied to lawns that can cause geese to become ill often backfire and can be absorbed by raptors that consumer the geese, and the introduction of natural predators like red foxes have also caused new problems for some municipalities.

For now, I’ll enjoy their raucous flights overhead as our harbinger of fall.

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