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Townsend's Warbler
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2001 Landbird Inventory
Early in the morning, before the sun peeks over the eastern horizon,
go outside and try to count every different bird that you see or
hear. How many did you survey? Could you identify any of them?
North Cascades National Park did this same survey for the total
park area of almost 700,000 acres. Actually, researchers didn't
go to every spot on the park map, but surveyed sample points (locations)
throughout the park to get a general idea which birds lived there.
Researchers were trained and even tested on bird calls and on their
ability to make visual identifications of bird species—some
birds were as large and obvious as a great horned owl, others as
tiny and fleeting as a rufous hummingbird.
Each morning the researchers woke up hours before dawn and hiked
to their survey locations over steep and precipitous terrain. For
a few hours they recorded each species they heard or saw within
a 50-meter radius. They did this survey for 640 points throughout
the entire park. A computer chose random points on the map to help
keep the science unbiased, otherwise some of the researchers may
have chosen their favorite hiking locations as survey points! But
with a computer making the choices, some of these randomly chosen
locations were on terrain so steep and dangerous that the experiment
needed to be modified in the field.
While at each site, surveyors recorded detailed information about
the area. The noted what the habitat was like, whether there were
shrubs or trees, or if they were in a barren landscape of rock and
talus. In the final report 24 different habitat
types were recorded and data was analyzed according to these
habitats. Knowing what habitat birds live in helps scientists know
how to protect a species—because protecting habitat is the
first step in protecting a species.
When the summer was over, researchers counted 4,936 birds and
recorded 104 different species.
Compare these two data sets below. This is a sample chart from
the final report. Which habitat type is most likely to be preferred
by Western tanagers? Where would you go in North Cascades to most
likely find a Western tanager during the summer? Click on the habitat
type to see if you are correct.
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