 What do FeederWatch data tell us? When thousands of FeederWatchers in communities across
North America count birds and send their tallies to the FeederWatch database, the result
is a treasure trove of numbers, which FeederWatch scientists analyze to draw a picture of
winter bird abundance and distribution.
FeederWatch data show which bird species visit
feeders at thousands of locations across the continent every winter. The data also
indicate how many individuals of each species are seen. This information can be used to
measure changes in the winter ranges and abundances of bird species over time.
Why are FeederWatch data important?
With each season, FeederWatch increases in importance as a unique monitoring tool for more than 100 bird species that winter in North America.
What sets FeederWatch apart from other
monitoring programs is the detailed picture that FeederWatch data provide about weekly
changes in bird distribution and abundance across the United States and Canada. Importantly, FeederWatch data tell us where birds are as well as where they are not. This crucial information enables scientists to piece together the most
accurate population maps.
Because FeederWatchers count the number of
individuals of each species they see several times throughout the winter, FeederWatch data
are extremely powerful for detecting and explaining gradual changes in the wintering
ranges of many species. In short, FeederWatch data are important because they provide
information about bird population biology that cannot be detected by any other available
method.
View FeederWatch
results, and learn more about their signficance, by clicking
on the Explore Data button above.
How do scientists know when a species is at risk?
Population sizes
of many species vary from year to year. Downward trends
for two, three, or even more years may not indicate actual
population declines; in fact, such trends may simply reflect
short-term weather patterns or other variations in natural
food supply and abundance. Sometimes, however, the data
reveal a long-term population decline of a particular species.
When bird population scientists become aware of such a trend,
they evaluate what they know about the species, its habitat,
and other factors that may be causing its decline. For example,
is the species' food in short supply? Has the amount of
suitable habitat changed on the species' breeding or wintering
grounds? Has a potentially competitive species shown a population
increase?
For example, FeederWatch
data from Florida showed that the winter population of the
Painted Bunting declined steadily since the 1980s. This
information, combined with complementary data from the Breeding
Bird Survey (showing that breeding populations of Painted
Buntings have declined at a rate of about 4 percent per
year) led the Florida Game and Fresh Water Fish Commission
to begin a systematic monitoring program of bunting populations
so they could learn how to protect them.
So, by combining
all they know about a species from monitoring data and intensive
research projects, scientists can begin to understand why
a species is declining, and to make recommendations for
its recovery before it is too late. |
