Waterfowl Species Abundance an indicator of wildlife sustainability in British Columbia's Interior

What is Happening?

Since 1988 the total number of waterfowl counted in spring (April-May) surveys throughout British Columbia's interior wetlands (see location map) have steadily increased, peaking in numbers in 1998 and then gradually decreasing. In 2004, there were an average of 6,289 ducks recorded per survey (4,576 diving ducks and 1,713 dabbling ducks). This represents a 17.5 % decrease below the 1988- 2003 long-term average.

The waterfowl observed in the surveys are ducks that breed in the area or are migrating to breeding grounds in Alaska or northern Canada (Yukon, NWT, or Alberta). These counts therefore reflect not only the local population but also to an extent the condition and size of waterfowl populations of other areas. The recent decreasing trend in waterfowl numbers mirror the decreases seen in North American waterfowl populations as a whole (U. S. Fish and Wildlife Service. 2004).

Source: Breault 2005. Environment Canada, Pacific Wildlife Research Centre, Delta, BC. Note the mean number of waterfowl is an average of 6 replicate ground surveys conducted on a fixed set of wetlands in April-May of each year.

GRAPH DATA

While diving ducks are more numerous and have increased fairly consistently from 1988 to 1996 and then in 2002, dabbling ducks have fluctuated widely with the highest counts for the database reported in 1998. In 2004, there were 24.4% less dabbling ducks counted than in 2003, representing a 35.0% decrease below the 1988-2003 long term average. In 2004, diving ducks counts were 23.4% below 2003 with a 8.3% decrease below the long term (1988-2003) average.

Counts of breeding pairs of waterfowl increased up to 1995, but thereafter declined. In 2004, the number of breeding pairs was down 11.6% from 2003 and 22.4% lower than the 1988-2003 long-term average. This continued long-term decline was observed in both diving and dabbling duck breeding pairs and for most of the common species of both groups. Some caution must be taken in interpreting changes in breeding pairs counts. This survey covers a fixed number of wetlands. On wet years, when additional wetlands become available, waterfowl disperse from permanent wetlands into this new habitat, resulting in lower abundance in surveyed areas. Under dry conditions, when the remaining wetlands are either semi-permanent or permanent water bodies, this bias is low. The current fixed number of wetlands is therefore not well-suited to track habitat changes. The last six years have been very dry in central and southern British Columbia with the spring of 2004 being driest encounteres since the surveys were initiated in 1988.

Why is it Happening?

It is difficult to determine whether the above trends are linked to the breeding or wintering areas or both. Various factors are likely contributing to the changes that are occurring. They could be related to natural or human-caused changes in habitat availability, variations in the local/global climate, wildlife management and hunting pressure, forest exploitation, agriculture, ranching, mining, and urbanization. As pointed out above, the limitations of the design of the survey may also limit its ability to monitor changes in waterfowl abundance.  However, one factor which is mirroring the increase in numbers of diving ducks, is the declining trend in hunting and harvest of ducks in BC. The estimated number of active hunters and number of ducks harvested have steadily declined over the last two decades. This declining trend in harvesting has also been documented in other parts of Canada and the USA. 

Source: Canadian Wildlife Service National Harvest Survey, 1974 to 2002, reported in Breault (2005). Note that the fall year is equal to the fall of the current year plus the spring of the coming year, e.g. 1997 = fall 1997 + spring of 1998.

GRAPH DATA

According to the Canadian Wildlife Service National Harvest Survey, there were only 4,021 active waterfowl hunters in 2003-2004, and this number has been declining overall for more than 20 years. The 2003-2004 estimate of active waterfowl hunters was 64% lower than the 1974-2003 long-term average. Only 51,989 ducks were harvested in 2003-2004 or 59.8% lower than the 1974-2003 long-term average and on average 97% of the ducks harvested were dabbling ducks.

Why is it Significant?

BC's Interior waterfowl community, which is made-up of approximately 23 waterfowl breeding species, is one of the most diversified in Canada. Its predominance of cavity-nesting species (Barrow's Goldeneye and Bufflehead) also sets this waterfowl community apart from other regions in Canada. BC is believed to be home to over 60% of the world's population of Barrow's Goldeneye on a year-round basis.

BC's Interior region is not only an important breeding area for waterfowl but also an important area during spring and fall migration and during wing molt.

Waterfowl have an important economic value to British Columbia both in terms of hunting (consumptive use) and viewing of bird species (non-consumptive use). Surveys conducted since 1981 on the importance of nature to Canadians have tried to estimate and assess this economic value of nature (including waterfowl).  Although the statistics are not specific to waterfowl nor to the interior region of BC, it was estimated that in 1996 $1,938 million was spent by residents of BC on nature-related activities (Du Wors et al. 1999). In 1991, these expenditures were only $977.2 million, yet they supported 20,281 jobs (Filion, et al. 1993). In 1991, over $174 million, or 17.8%, was spent on hunting (includes birds and mammals), whereas almost $572 million, or 58.6%, was spent on primary non-consumptive wildlife related trips or outings.

This difference is attributable to the fact that the number of days of participation in primary non-consumptive trips or outings has been increasing since 1981, whereas the number of days spent hunting is in decline.

Even though there has been a declining trend in hunting since the late 70's, the economic importance of expenditures and benefits derived from wildlife-related activities in BC continues to be significant for the provincial economy.

What is Being Done?

On-going waterfowl use surveys of BC's interior wetlands have been conducted since 1988, by an inter-agency project called the Cooperative Waterfowl Survey. The inter-agency team, with representatives from the Canadian Wildlife Service, Ducks Unlimited Canada, the BC Wildlife Branch, the Canadian Parks Service, biological consultants and volunteers from local naturalist clubs, assesses the abundance of breeding and migrating waterfowl in about 400 wetlands located on private property, native, provincial and federal lands throughout the BC Interior. The results of these surveys are used in the annual evaluation and assessment of hunting regulations. The annual monitoring of waterfowl populations is one of the tools used to manage waterfowl populations and track biodiversity in the Pacific and Yukon Region.

The Canadian Wildlife Service and Ducks Unlimited (Canada) are working in developing techniques to estimate the total wetland and breeding waterfowl abundance in British Columbia. A preliminary data analysis suggest that 750,000 pairs of waterfowl breed in the southern interior portion of the province, primarily on wetlands of less than 1 hectare.

For more information contact: Andre.Breault@ec.gc.ca

Check the following sites for additional information on this indicator:

• CWS - Hinterland Who's Who
• CWS - Hinterland Who's Who - Benefits of wildlife
• CWS - Hinterland Who's Who - What you can do for wildlife
• CWS - Waterfowl
• Breeding Bird Survey
• Canadian Bird Trends
• EnviroZine - Environment Canada's on-line newsmagazine

The following Web sites are not under the control of Environment Canada (EC) and they are provided solely for the convenience of users. Environment Canada is not responsible for the accuracy, currency or the reliability of the content. Environment Canada does not offer any guarantee in that regard and is not responsible for the information found through these links, nor does it endorse the sites and their content. Users should be aware that information offered by non Government of Canada sites that are not subject to the Official Languages Act, and to which Environment Canada links, may be available only in the language(s) used by the sites in question.

• WetKit - linking people with practical tools for better understanding and managing wetlands
• Ducks Unlimited
• Yukon Waterfowl and Wetlands
• North American Breeding Bird Survey Home
• US Fish & Wildlife Service
• US Fish & Wildlife Waterfowl Migratory Bird Population Status

For references used in this indicator click here.