Possessing annual estimates of black duck population characteristics, including abundance, sex and age structure, and vital rates (i.e., survival and recruitment) is critical to fulfilling the mission of the BDJV and achieving the goals of the NAWMP. These estimates form the basis of black duck adaptive management and allow researchers and managers to assess model predictions, evaluate responses of black ducks to management, and track progress towards NAWMP goals. Black duck population monitoring consists of three complementary programs: pre-season banding, the Mid-Winter Inventory, and Eastern Breeding Waterfowl Survey.
Monitoring Seasonal Survival Rates (two-season banding program)
Pilot Project: Banding moulting males in Ontario’s Hudson Bay Lowlands
The BDJV has provided support to the Ontario Ministry of Natural Resources to test field methodology to capture moulting male black ducks in northern Ontario. The objective is to determine the feasibility of increasing the number of adult black ducks banded in Ontario annually by targeting moulting birds known to gather in the Hudson Bay Lowlands. Biologists intend to increase the banded total in Ontario by 300-500 per year to help balance the continental distribution of banded black ducks and improve estimates of vital rates.
Assessing methodology to estimate black duck pre-hunting season age ratios
Dim OpType OpType = Request.Querystring("Type") If OpType = "Banding" Then %>
Banding: Banding is an important tool in migratory bird management. When combined with population and harvest data banding provides important information about population dynamics and structure, distribution, and derivation of harvest. This information in turn helps guide management activities. The first “Continental Waterfowl Banding Program” was issued jointly by CWS and USFWS in 1959. This cooperative plan, and subsequent updates in 1967, 1971, 1975, 1985, and 1989, has served as the principle framework for waterfowl banding and provides specific banding goals (i.e., quotas) by region for the black duck. Another update to the plan is currently in progress. Pre-season banding of black ducks is coordinated by two programs, the Eastern Canada Cooperative Banding Program (ECCBP) and the Northeast States Banding Program (NESBP). The ECCBP was initiated in 1963 to focus efforts on duck banding in eastern Canada and to obtain representative samples of black ducks and mallards. The ECCBP is coordinated by the banding committee of the Atlantic Flyway. Funding for the ECCBP is provided by the Atlantic Flyway, state and provincial agencies, and the BDJV. The NESBP is funded by the BDJV to increase the number of black ducks and mallards banded in northeastern U.S.
Table 1. Number of black ducks banded in the pre-season (July–September) 2010 and 2009.
Note: Pre-season Banding Data obtained from the Bird Banding Laboratory on 20 June 2011.
<% ElseIf OpType = "MidWinter" then %> Mid-Winter Inventory: The Mid-Winter Inventory (MWI; also known as the Mid-Winter Survey) has been conducted in the United States since 1955. Because it provides the longest time series of black duck abundance data the MWI have been used extensively in research, particularly population modeling. However, the MWI has several limitations. First, it is only conducted in the United States so it does not provide an estimate of the entire wintering population. Second, recent research suggests the distribution of wintering black ducks may have shifted north, further limiting the usefulness of the MWI. Third, the MWI lacks the precision necessary to monitor population changes and does not provide estimates of variance. Finally, the MWI cannot be used to differentiate regional changes in breeding populations. A MWI has been conducted in Ontario by Environment Canada-Canadian Wildlife Service since 2002 and provides an index of abundance along the north shore of lake Ontario.
<% ElseIf OpType = "BPOP" then %> Eastern Breeding Waterfowl Survey (BPOP): Information and data on the black duck breeding population have been limited because the species breeds in eastern Canada, which is outside the traditional mid-continent breeding survey area (Fig. 1). Due to lack of information about the breeding population and limitations of the MWI, a breeding population survey program was initiated in 1990. The breeding population survey is conducted throughout black duck breeding range by the CWS and USFWS. However, the two agencies use different protocols. The CWS conducts plot surveys from helicopter, whereas the USFWS survey consists fix-winged transects. Estimates from the two surveys are integrated in a hierarchical model to produce a single estimate of the black duck breeding population. For the foreseeable future, the mid-winter and breeding population surveys will be conducted and used in research and management. However, it is anticipated that research and management will place greater reliance on the breeding population survey as the time series lengthens. The goals of the BDJV population monitoring program are to assess trends in the black duck population to evaluate progress towards NAWMP goals and develop, implement, and refine monitoring methodology. The USFWS produces black duck breeding population estimates at two different spatial scales-“core” and “total”. The core survey area has been surveyed since 1990 and the resulting data were used to calculate the NAWMP population goal and in the development of the Black Duck Adaptive Harvest Management framework. The total survey area has been monitored since 1998.
In 2010, the estimated breeding population (in the core area) was 565,000 (95% CI 479,000—624,300). This estimate was 5% lower than the 2009 estimate (596,200 [95% CI 523,000—684,300) and 32% lower than the NAWMP Population Goal (830,000). The 2010 estimate constitutes the 4th consecutive decline in the estimated black duck breeding population (in the core survey area). The 2010 estimate for the entire survey area 804,000 (95% CI 667,000—1,040,000) which is 11% lower than the 2009 estimate (900,000 [95% CI 735,000—1,200,000). However, at the scale of the total survey area the black duck population has not shown a consistent decline over the past 4 years.