How many kinds of Canada geese are there? Most people would
answer, ³One, with the black head and white cheek patch.² Although
all Canada geese look similar, there are at lease 11 subspecies
in North America. These range in size from the giant Canada
goose, adults average about 12 pounds, to the cackling Canada
goose, adults average about 3 pounds. In addition to differences
in size, some subspecies of Canada geese nest in northern Canada
and migrate to wintering areas in the United States. Other
subspecies are basically non-migratory, spending their entire lives
in relatively small areas.
So what kind of Canada geese do we have in Maryland? Maryland
boasts a large population of migratory birds that arrive in
late-September or early October. In late February they return
to their nesting areas in northern Quebec. Other Canada geese in
Maryland are basically non-migratory; theses ³resident² Canada
geese nest and winter within the state.
Are resident Canada geese simply migratory geese that decide not
to migrate? A few resident geese may be migrants that were
crippled during the hunting season. However, most resident geese
are non-migratory because they are descended from races of
Canada geese that never migrated, mainly giant and western
Canada geese. These races of Canada geese are not native to
this area. They have become established throughout the flyway
during the last 50 to 75 years through stocking by private
individuals and public agencies, and releases of decoy flocks
during the 1930's.
In Maryland, most resident Canada geese are found west of the
Chesapeake Bay, mainly in the Piedmont region. A recent survey
estimated there were in excess of 3000 breeding pairs with a
total population well over 10,000. They are common on ponds,
lakes and golf courses, mainly in urban and suburban areas. The
stateıs population of resident geese is increasing, even as our
migrant flocks decline.
Resident geese have several advantages over migrants that help
explain these different population trends. One advantage is that
they tend to live in urban areas where hunting is not allowed.
The result is that they live longer; 15 to 25 year-old resident
geese are not uncommon. Resident geese also lay larger clutches
of eggs and nest in a more hospitable environment than migrants,
so potentially they can produce more young.
Migrant Canada geese that winter in Maryland are found mainly on
the Eastern Shore where hunting pressure is high. They nest in
northern Quebec where weather conditions are critical to the
success or failure of the nesting season.
Although resident geese have positive attributes, including
aesthetic value, these attributes are often overshadowed by
problems when resident geese become numerous. Complaints of
nuisance geese are frequent and increasing. Common complaints
include fouling of lawns, ponds, gardens, beaches and golf
courses with droppings and feeding damage. Complaints come
mostly from the western shore, where resident geese and people
are most numerous. However, nuisance complaints are also
starting to occur on the eastern shore. If resident geese were
to increase to large numbers on the eastern shore, damage to
agriculture crops could be severe, particularly when corn and
soybeans are sprouting.
The outlook for Canada geese in Maryland is quite different for
resident and migrant birds. Urbanization provides ideal habitat
for residential geese and their numbers are likely to increase.
However, the capacity of people to live with more resident geese
may be nearing a limit, particularly on the western shore.
Nuisance complaints are likely to increase as resident goose
numbers grow. The future of Marylandıs migrant flock is still
uncertain. However, increasing our resident flock to compensate
for the decline of migrants is not the answer.
Environmental Systems Analysis, Inc. (ESA) is responsible for
the design, construction, monitoring, maintenance and management
of water resources facilities (wetland mitigation, ponds, SWM
facilities) and we find ourselves frequently managing for goose
related impacts. Specific problems include algae blooms on ponds
fueled by enriched fecal defecate and loss of riparian vegetation
along the wetland pond fringe due to excessive feeding pressure.
In order to diversify their diet, geese will feed on many
varieties of grasses, sedges, rushes and forbs. Shoreline
vegetation may be completely denuded from ponds where resident
geese occur, causing functional degradation (i.e. habitat,
erosion, turbidity, loss of nutrient and pollutant uptake by
hydrophytic plants).
An average 10 pound adult goose will generate its own body weight
in excrement each month !
Excrement entering ponds via storm runoff can cause warm weather
algae blooms. These blooms are unsightly and often treated with
algaecides. As the algae quickly dies, dissolved oxygen may be
greatly reduced, stressing or killing pond fish.
Geese generally imprint to the waterbody where they were born and
raised, meaning that they will typically reside or return to
breed on the pond where they were reared. Resident geese prefer
open lawn and water bodies. This provides them an unobstructed
view for foraging and clear escape access to the pond for
protection. Geese also need a wide berth for take-off and
landing. Thatıs why golf courses are so attractive.
ESA, Inc has developed integrated pest management strategies for
goose control. Biological and mechanical options may include
wetland plantings which are distasteful to geese, and shrubby,
coarse vegetation inhibiting movement in and out of the water as
well as ability to see predators. Low rise fence bands along
the waters edge or lawns, fencing grids to totally prevent pond
access, swan decoys, egg shaking, oiling and/or freezing are
but a few other management options.
If you are having problems with excessive geese or with any
aspect of your water resource concerns, call us at
410-267-0495. We have solutions based on sound scientific
and ecological principles. Treat your causes, not your
symptoms.
