Conservation of the american black duck
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Conservation of the American Black Duck. A presentation by Patrick Gaskin. American Black Duck. Large dabbling duck of the North East A species of special concern Combined conservation efforts between the US and Canada may have the numbers on the rise. Background Information.

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Conservation of the american black duck

Conservation of the American Black Duck

A presentation by Patrick Gaskin


American black duck

American Black Duck

  • Large dabbling duck of the North East

  • A species of special concern

  • Combined conservation efforts between the US and Canada may have the numbers on the rise


Background information

Background Information

  • Order- Anseriformes

  • Family- Anatidae

  • Sub-family- Anatinae

  • Tribe- Anatini

  • Anas rubripes

  • Other names

    • Canard noir (French) Andande sombrio americano (Spanish)


Description

Description

  • Body is a dark blackish brown

  • Head and neck are lighter

  • Legs and feet are red

  • White linings under wings

  • Blue speculum is not bordered by white

    • Similar to female Mallard and Mottled Duck at a distance

  • Immature are similar to adults

    • Underparts more heavily streaked


Description continued

Description continued

  • Size: 54-59 cm (21-23 in)

  • Wingspan: 88-95 cm (35-37 in)

  • Weight: 720-1640g (25.42-57.89 oz)

  • Population about ½ million

  • Voice is a raspy “quack”


Differences among the genders

Differences among the genders

  • Male is slightly larger

  • Bill colors differ

    • Male has a yellow bill

    • Female has a green bill often with black mottling

  • Males legs are a brighter red than female


Similar species

Similar species

  • Female Mallard


Eclipse male mallard

Eclipse Male Mallard


Mottled duck

Mottled Duck


Mallard black duck hybrid male

Mallard/Black Duck hybrid male


Range

Range

  • Breeds: Eastern Canada and the North East US

  • Winters: Southern Canada to the Gulf Coast, as far west as Iowa

    • SE refuges especially

      in TN and AL

  • Most migrate along the Atlantic Flyway

    • but about 1/3 use the Mississippi Flyway


Habitat

Habitat

  • Breeds in a variety of wetland habitats

    • Salt marshes, beaver ponds, river islands and boreal bogs

      • Often prefers wooded habitats (boreal forests and parkland ecotones)

    • Nest typically in upland locations

  • Winters in salt water along coasts, but also in a variety of freshwater areas inland


Other info

Other info:

  • Diet is diverse

    • Higher in animal protein than many other dabblers

      • Mussels, snails, and gizzard shad

    • Also grains and seeds as other dabblers

      • Filter feeds at surface and also tips up in shallow water


Other info continued

Other info continued…

  • Nest in vegetation in upland locations (boreal forest and parkland ecotones)

    • Nest is lined with down

    • 1-17 eggs in clutch, typically 9-10 on average


What happened

What happened?

  • Populations declined in the mid-20th century

  • Several factors have contributed to the decline


Reasons for population decline

Reasons for population decline

  • Loss of habitat (both breeding and non-breeding areas)

  • Over-harvesting by hunters

  • Interbreeding with the Mallard

  • Competitive disadvantages to Mallard

    • Mallards may take over some breeding spots


What is being done

What is being done?

  • Initially population counts and surveys

    • Essential to measure the scale of the problem before proceeding with any management options


The findings

The Findings:

  • American Black Duck wintering populations have been declining since 1955

    • This led to pressure to prohibit hunting of this duck

  • US government decreased the daily bag limit for this species in 1983

    • Canadian government followed suit in 1984

      • Further tightened the harvest limits in 1989 and 1990

    • Current daily bag limit in KY is 1 Black Duck


This didn t accomplish all that was hoped for

This didn’t accomplish all that was hoped for:

  • Despite these measures, the Black Duck remains a source of concern due to:

    • Hunting pressure

      • Some hunters mistake Black Ducks for female Mallards, or ignore possession limits

    • Habitat loss and degradation

    • Competition and hybridization with the Mallard

  • However, since 1989, the average number of American Black Ducks killed by hunters has decreased by 26% in Canada, and by 44% in the US


Habitat loss and degradation

Habitat loss and degradation

  • Mid Atlantic coastal areas have been affected by ditch building

    • To control mosquito populations

  • Coastal lagoon and housing developments

  • Clearing and logging

    • Losses of forested wetlands decreases suitable breeding habitats

  • Environmental contamination by pollutants

    • Formerly affected by DDT and lead poisoning

      • DDT banned by US in 1971, and lead shot banned twenty years later


Interbreeding with mallards

Interbreeding with Mallards:

  • Compounded by the introduction of captive-raised Mallards into Black Duck breeding ranges

    • Since 1940, 1.7 million game-farm Mallards have been released in American Black Duck ranges

      • Not only leads to increases in hybridization, but also to increases in competition for breeding sites

  • Leads to “diluted” stock of Black Ducks

    • Decline of American Black Duck as a distinct species


Nawmp

NAWMP

  • In 1986, the US and Canada joined forces to institute the North American Waterfowl Management Plan (NAWMP)

    • Mexico signed on in 1988


Main goal of nawmp

Main goal of NAWMP

  • Restore waterfowl populations to their 1970’s (1970-1979) winter levels

    • The urgency of restoring the Black Duck led the NAWMP to set up the Black Duck Joint Venture (BDJV)

      • Between the US, Canada, and Mexico


Black duck joint venture mandate

Black Duck Joint Venture mandate:

  • Facilitate and coordinate the gathering of information

  • Improve our knowledge of the species

  • Guide conservation and manage most decisions


Three programs were established under the venture

Three programs were established under the venture:

  • Survey program

  • Banding program

  • Research program


Survey program

Survey Program

  • The survey data has been analyzed to determine population trends and changes

    • Birds are counted from aircraft

    • Count all pairs and lone males in a breeding habitat

    • The numbers are expressed as breeding pairs


American black duck trends of breeding pairs since 1990

American Black Duck Trends of Breeding Pairs since 1990


Banding program

Banding Program

  • Coordinated by the Atlantic Flyway Eastern Cooperative Banding Agreement under the BDJV

  • Determine the relative distribution of kills and sport harvest rates

    • Used to calculate the survival rates for the populations sampled

    • These can be done using program ESTIMATE or others


Research program

Research Program

  • Identify the causes for Black Duck population declines

  • Identify factors that may help the species to recover

    • Attempt to determine the relative importance of the factors influencing American Black Duck numbers and population dynamics


At the beginning of the program

At the beginning of the program:

  • Research efforts focused on measuring annual American Black Duck productivity compared to that of Mallards


More recently the priority has been on the relation between

More recently the priority has been on the relation between:

  • Variation in recruitment rates and landscape configuration

  • Habitat productivity

  • The presence of the Mallard


Conservation of the american black duck

  • The current focus of the program is on Adaptive Harvest Management related studies


Adaptive harvest management ahm

Adaptive Harvest Management (AHM)

  • Seeks to reach a long-term harvest objective

    • Decisions being annual harvest regulations (quota)


Tasks of ahm

Tasks of AHM

  • Using the analyses completed under previous work orders, develop a model set for use in adaptive optimization

    • Emphasis devoted to initiating a very simple AHM model

      • Exploring the consequences of finer vs. coarser resolution in objective, decision space and state space, and of alternative model weightings


Conservation of the american black duck

  • Working with BDJV and other stakeholders, develop and incorporate objective functions

    • Formulation of a suitable objective function is critical

      • A matter for resolution among managers and policy makers

    • Concept of “sustainability” is at the core of most natural resource management


Conservation of the american black duck

  • Working with BDJV and other stakeholders, develop alternatives

    • Joint Black Duck-Mallard objective

      • Joint consideration of harvest regulations for each species

        • Restrictive for both species

        • Liberal for both species

        • Restrictive for one, liberal for the other


Conservation of the american black duck

  • Definition of state space and resolution of monitoring efforts

    • Important state variables to consider

      • Estimates of breeding (wintering, or both) Black Duck populations

      • Estimate of breeding habitat conditions

      • Estimates of breeding Mallard populations


Conservation of the american black duck

  • Evaluate the potential impacts of model resolution and management scale on optimal decision making, with respect to gain in objective value, vs. costs Evaluate the potential impacts of model resolution and management scale on optimal decision making, with

    • Reconfigure models to allow for multiple populations and stratified objectives and decision making

    • Evaluate the consequences of spatial stratification on

      • The ability to meet resource objectives

      • The tradeoffs in terms of complexity and costs of finer vs. coarser scale management


Conservation of the american black duck

  • Depending on the results of 1-5, develop a working adaptive management protocol for Black Ducks

    • Possible joint Black Duck-Mallard protocol

      • Recommend one or more forms for the objective function

      • Recommend sets of decision alternatives

      • Develop a working model set and optimization procedure

      • Recommend the scale and intensity at which relevant state variables and other parameters should be measured


Conclusions

Conclusions:

  • Combined conservation efforts of the US and Canada may have numbers on the rise

    • The BDJV graph showing breeding pair distribution trends shows a higher population of breeding pairs since 1994

      • Populations still experience rising and falling trends, but they remain higher than the low population count of 1994

      • The steady decline in breeding pairs from 1990-1994 looks to be halted


Conservation of the american black duck

  • No solid evidence of major decreases in quality or quantity of breeding habitat for Black Ducks since the late 1980’s

    • Except in specific areas, such as those disrupted by hydroelectric projects

    • An increase in beaver populations may be helping to create more wetland breeding habitat

  • Populations are currently steady

    • But only about ½ as many Black Ducks as there were in the early 1950s

  • Still face problems with Mallard competition and hybridization

    • Adaptive harvest management techniques could be employed to ease the hunting pressure on American Black Ducks, while working to control Mallard populations in areas shared by the two species


Sources

Sources

  • Canadian Wildlife Service (CWS), Quebec Region www.lavoieverte.qc.ec.gc.ca/faune/sauvagine/html/historic.html

  • Cornell Lab of Ornithology

    www.birds.cornell.edu

  • Hinterland Who’s Who

    www.hww.ca.com

  • Black Duck Adaptive Management Working Group

    http://coopunit.forestry.uga.edu/blackduck/overview.html


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