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 Although northern pintails are very abundant in North America, their status has deteriorated over the last 30 years (see long-term pintail breeding population graph at left).
In spring 1998, the pintail breeding population (BPOP) was only about 2.5 million as determined
during the May Breeding Population and Habitat Survey (May Survey),
but edged up to 3.2 million in 2001
(2001 Waterfowl Population
Status Report issued by the U.S.
Fish and Wildlife Service. See the Division of Migratory
Bird Management homepage for this and other population status reports).
This population was well below the long-term
average and the objective level established by the North American Waterfowl Management Plan
(5.6 million). Even though the estimated number of prairie wetlands (May Ponds) indexed by the
May Survey increased to record high levels in Canada and the U.S. subsequent to the long drought
of the 1980s and early 1990s, pintail populations did not increase as expected based on the
historical relationship between these two indices. Each peak in pintail numbers since that in
1955-56 has been successively lower than the one before and each low point (1960s and 1980s-early
1990s) has been lower than the one before. In contrast, all other species of prairie nesting
dabbling ducks rebounded to average or above average (in some cases, record) numbers as of May
1997, as pond numbers increased. For example, the mallard (Anas platyrhynchos) BPOP was
10% over the long-term average in 1996 and increased to 37% above the long-term average in 1997.
By 1999, the mallard BPOP was at an all time record high. Gadwalls (A. strepera) and
northern shovelers (A. clypeata) reached record high numbers in 1997, the BPOP for
blue-winged teal (A. discors) and green-winged teal (A. crecca) increased to more
than 40% above long-term averages, and in 1997 American wigeon (A. americana) were 20%
above long-term averages. Also, all of these species were above objective levels set by the
North American Waterfowl Management Plan (NAWMP). In stark contrast, in 1996 the pintail BPOP
was nearly 40% below the long-term average and 60% below the NAWMP objective level. Even after
a 30% increase in BPOP in 1997, pintails remained 19% below the long-term average and 36% below
the NAWMP goal. In 1998, pintail BPOP declined 29% to 2.5 million as parts of the prairie region
important to pintails again suffered dry conditions as May Ponds declined. In 1999, good wetland
conditions returned to most of the prairie and pintail BPOP increased to just over 3 million.
The minimal recovery of the North American pintail population is perplexing given the very large
populations attained during previous periods of abundant May Ponds (1950s and 1970s), and the
current high populations of other ducks. Clearly, there is a need to more fully understand
pintail population dynamics and determine what is limiting pintail recovery so that useful
remedies may be applied.
Ultimately, waterfowl managers need to understand effects of winter and spring migration habitat quality, relative to nesting habitat quality and extent, on body condition of nesting pintail hens, settling patterns and habitat selection across nesting regions, and production of young ducks. The first step in this effort is to identify spring migration routes and critical staging areas where pintails acquire nutrients prior to arrival in nesting regions on the prairies and in Alaska. Further, managers need to identify distribution patterns of pintails relative to May Pond abundance and distribution and to the location of May Survey strata. Postnesting distribution needs to be known to link molting lakes with specific nesting regions, measure population exposure rates to perennial botulism lakes, and assess efficiency of operational banding sites in representing pintail breeding distribution. These data are needed for drought and wet years where most pintails nest, including the prairies of southern Canada and the northern Great Plains in the U.S. (North and South Dakota, eastern Montana, western Minnesota), and in Alaska and other northern areas. |
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