CANADA GOOSE
HARVEST MANAGEMENT IN IOWA
By Guy Zenner, Waterfowl
Research Biologist
Waterfowl hunters in Iowa
harvest Canada geese from 3 of the 11 races of Canada geese that are found
in North America: giant Canada geese(Branta canadensis maxima), interior
Canada geese (B. c. interior) and Richardson’s Canada geese (B. c. hutchinsii).
In some cases, these races are further divided into subpopulations for
management purposes. For example, the Eastern Prairie Population
(EPP) and Mississippi Valley Population (MVP) are subpopulations of interior
Canada geese. Giant Canada geese, the largest of the 11 Canada goose
races (9+ lb.), nest in southern parts of the Canadian provinces and from
the Midwest to the Atlantic coast. EPP and MVP Canada geese, subpopulations
of the interior race of Canada geese (6-9 lb.), nest on the west and south
sides of Hudson Bay. Tall Grass Prairie Population (TGPP) Canada
geese are comparatively small geese (<6 lb.), often referred to as "hutchies",
that nest in the Arctic on Baffin Island. With the exception of Giants,
these groups of geese were named during the mid 20th century for their
primary wintering sites: MVP for the lower Mississippi Valley, EPP
for geese that wintered around Swan Lake in MO and TGPP for the small Canadas
that wintered in the tall grass prairie region that stretches from Iowa
to Louisiana.
For most of the 20th century,
the status of subarctic and arctic-nesting Canada goose populations (EPP,
MVP and TGPP) determined hunting regulations for all Canada geese in the
Mississippi Flyway. Giant Canada geese were not considered in the
equation because their numbers were insignificant (an estimated 20,000
in the early 1960’s). When sub-arctic and arctic-nesting Canada goose
populations were high, hunting regulations were liberal. In Iowa,
for example, a liberal Canada goose hunting season was 70-days long with
a 2-bird bag limit. When the Canada goose populations were low, hunting
opportunities were restricted. A restricted Canada goose season in
Iowa was usually 45 days long with a 2-bird bag limit, although seasons
were as short as 23 days with a 1-bird bag in the 1970’s.
Today, Canada goose hunting
regulations are complicated by increasing numbers of giant Canada geese,
the mixing of different races of Canada geese on migration and wintering
areas that used to be specific for a single population, and the fact that
some of these populations are increasing while others are decreasing.
To add to the challenge of managing harvests of these birds, all races
or populations of Canada geese are not harvested uniformly over their migration
ranges and, except for TGPP which are noticeably smaller, are indistinguishable
from each other when on the wing. These difficulties, however, do
not relieve the states or the U.S. Fish and Wildlife Service (USFWS) of
their legal responsibility to control harvests so that all distinct populations
are maintained at viable levels.
Over the years, the Iowa
DNR has cooperated with the USFWS and other states and provinces in the
Mississippi Flyway to provide reasonable hunting opportunities within the
limits of the status of these various Canada goose populations. This
has resulted in adjustments to season length and bag limits from time to
time to reduce harvests of one or more groups of geese. It is important
to remember that the regulations setting process is a cooperative, democratic
process (see The Process of Setting Hunting Regulations). Cooperation
among states and provinces is essential to effectively manage migratory
waterfowl resources. The process contains checks and balances that
enable a group of states to impose restrictions on another state or limit
another state’s harvest opportunity if the group feels the state’s hunting
season proposal is not in the best long-term interest of the resource that
they all share.
Hunters must realize that
when restrictive goose hunting regulations are put in place, they are,
in fact, designed to reduce their opportunity to shoot geese, thereby reducing
the goose harvest. Population status is very carefully considered
before any such restrictions are implemented. The restrictions, however,
must also be effective to see improvements in the status of the goose population
of concern. Because Canada goose migration chronology and staging
habitats have changed over time, hunting restrictions that were used in
the past to reduce harvests may not effectively reduce harvests today.
Changes in goose migrations and staging habits may require new and innovative
regulations to reduce harvests of geese from a specific population.
When restrictive regulations are in place, however, hunters should expect
to have something less than an ideal season. If a states restrictive
regulations do not reduce its harvest from the population of concern, other
states can take action, through the Flyway Council, to insure that more
effective regulations are used in the future.
The reproductive biology
of Canada geese also influences harvest restrictions. Canada geese
usually do not nest until they are at least 3-years old. Thus, young
geese have to survive 3 hunting seasons before they begin to reproduce.
Canada goose populations, therefore, do not recover rapidly after a population
decline. This delay may even be longer for subarctic and arctic-nesting
Canada goose populations because they have low reproductive rates (i.e.
first nest at age 4 and have small clutches) and high mortality rates (they
are hunted throughout a long migration). Canada goose hunting restrictions
designed to help a goose population recover nearly always remain in place
for 2 or more years.
The Mississippi Flyway
Council believes that a conservative approach to Canada goose harvest management
is in the best long-term interest of Canada goose populations and goose
hunters. Giant Canada goose populations, however, have complicated Flyway
Canada goose management strategies by creating the illusion that all Canada
goose populations are doing well and that hunting restrictions are unnecessary.
Succumbing to this illusion could have dire consequences for hunters.
For example, increasing
numbers of giant Canada geese masked the decline of the Southern James
Bay Population (SJBP) of Canada geese in the eastern Mississippi Flyway.
The SJBP was traditionally monitored through winter counts. When this population
was surveyed on its nesting grounds, it became painfully obvious that the
SJBP had declined substantially. The Flyway Council and the USFWS
took drastic steps to curb the harvest of geese from this flock, some areas
having only 16-day seasons. When the Atlantic Population of Canada
geese declined in the 1990’s, regular Canada goose seasons were closed
in most of the Atlantic Flyway despite overabundant giant Canada goose
populations. Even when giant Canada goose numbers are increasing,
the status of other Canada goose populations cannot be ignored. Hunting
regulations are often designed for the least common denominator.
In this case, the Canada goose population that is of greatest concern.
Special
Canada Goose Seasons
The challenge of managing
local Canada goose populations in conjunction with other less stable or
declining goose populations has led most states to implement some kind
of special early or late Canada goose season. These “special”
seasons are designed to provide hunters with additional opportunities to
harvest local giant Canada geese when few, if any, migrant Canada geese
are available to be harvested. In fact, until 1996, special early
Canada goose seasons could only be implemented in the Mississippi Flyway
where states could show that the expected goose harvest would be 90% giant
Canada geese. This was done using neckcollar observations of both
giant Canada geese and EPP and MVP Canada geese that had been marked on
their nesting grounds. In addition, the state implementing the special
season had to evaluate the season’s impacts on other goose populations
for at least 3 years to conclusively show that 90% of the harvested geese
were giants. Since MVP, EPP and giant Canada geese cannot be separated
by casual observation, biologists took specific measurements of wings,
legs and heads from harvested geese collected during the special season.
The combination of these measurements, along with the bird’s age and sex,
can be used to determine, with relative certainty, which population (EPP,
MVP or giant) the goose was from.
These evaluations were
conducted in many parts of the Mississippi Flyway during the 1980’s and
1990’s. Combined, they indicated that very few subarctic or arctic-nesting
Canada geese (EPP, MVP, or SJBP) migrate into the states before September
15. Consequently, in 1996, the USFWS permitted any state within the
Flyway to implement special early seasons for giant Canada geese between
September 1-15 without conducting a rigorous evaluation.
In Iowa, the giant Canada
goose population in the northcentral and northwestern parts of the state
appeared to have saturated most of the available nesting habitat in 1996
and was believed capable of sustaining some additional hunting pressure.
As a result, a special 2-day early September Canada goose season was implemented
in those regions. Hunters took advantage of this opportunity and
harvested 10,000 to 16,000 Canada geese during those special 2-day seasons
between 1996 and 1998. Nearly all the harvested birds were giant
Canada geese that had hatched in Iowa, although a few undoubtedly originated
in southern Minnesota.
At the time, it was not
known if our local Canada goose populations could maintain themselves in
the face of this additional hunting pressure. Some very recent information
suggests that they may not be able to. Because the status of our
own giant Canada goose population largely determines the goose hunting
opportunities and success across the state, this situation will be closely
monitored to ensure that these local populations remain at viable levels.
In other words, the special 2-day Canada goose season may not be open consistently
from year to year. Implementation of this special season will depend
upon the status of our local giant Canada geese.
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