What is the North American Breeding Bird Survey (BBS)?
The BBS is a long-term, large-scale, international avian monitoring program
initiated in 1966 to track the status and trends of North American bird
populations. The USGS Eastern Ecological Science Center and Environment Canada's Canadian Wildlife
Service jointly coordinate the BBS program.
Why was the BBS created?
In the mid-twentieth century, the success of DDT as a pesticide ushered
in a new era of synthetic chemical pest control. As pesticide use grew,
concerns, as epitomized by Rachel Carson in Silent Spring, regarding
their effects on wildlife began to surface. Local studies had attributed
some bird kills to pesticides, but it was unclear how, or if, bird populations
were being affected at regional or national levels. Responding to this
concern, Chandler Robbins and colleagues at the Patuxent Wildlife Research
Center developed the North American Breeding Bird Survey to monitor
bird populations over large geographic areas.
Although most concerns over pesticide use in North America have subsided
in recent decades, bird populations continue to be subjected to numerous
widespread threats including habitat loss, habitat fragmentation, land-use
changes, and other chemical contaminants. Today, the BBS continues to
monitor bird populations across North America and informs researchers
and wildlife managers of significant changes in bird population levels.
If significant declines are detected, their causes can then be identified
and appropriate actions taken to reverse them before populations reach
critically low levels.
How does the BBS work?
Each year during the height of the avian breeding season, June for most
of the U.S. and Canada, participants skilled in avian identification
collect bird population data along roadside survey routes. Each survey
route is approximately 24.5 miles long with stops situated ideally 0.5-mile apart. At each stop,
a 3-minute point count is conducted. During the count, every bird seen
within a 0.25-mile radius or heard is recorded. Surveys start one-half
hour before local sunrise and take about 5 hours to complete. Over 4100
survey routes are located across the continental U.S. and Canada.
Once analyzed, BBS data provide an index of population abundance that
can be used to estimate population trends and relative abundances at
various geographic scales. Trend
estimates for more than 420 bird species and all raw
data are currently available via the BBS web site.
How are BBS data used?
- The U.S. Fish and Wildlife Service,
Service, and Partners
in Flight all use BBS trends along with other indicators to assess
bird conservation priorities.
- BBS data were instrumental in focusing research and management action
on neotropical migrant species in the late 1980s, and on grassland species
in the mid-1990s.
- State Natural Heritage
programs and Breeding Bird Atlas projects often utilize BBS data to
enrich their databases.
- Educators often use BBS data as a tool to teach biological, statistical
and GIS concepts.
- More than 450 scientific publications have relied heavily, if not
entirely, on BBS data. The entire BBS bibliography is viewable here.
Laurel, MD, USA 20708-4038
Last Modified: 2/3/2023
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