Description

A study examined the association between nesting locations of the Northern Spotted Owl and availability of mature forests. Wildlife biologists identified 30 nest sites. The researchers selected 30 other sites at random coordinates in the same forest. On the basis of aerial photographs, the percentage of mature forest (older than 80 years) was measured in various rings around each of the 60 sites.

Usage

Format

A data frame with 60 observations on the following 8 variables.

Site

Site, a factor with levels "Random" and "Nest"

PctRing1

Percentage of mature forest in ring with outer radius 0.91 km

PctRing2

Percentage of mature forest in ring with outer radius 1.18 km

PctRing3

Percentage of mature forest in ring with outer radius 1.40 km

PctRing4

Percentage of mature forest in ring with outer radius 1.60 km

PctRing5

Percentage of mature forest in ring with outer radius 1.77 km

PctRing6

Percentage of mature forest in ring with outer radius 2.41 km

PctRing7

Percentage of mature forest in ring with outer radius 3.38 km

Source

Ramsey, F.L. and Schafer, D.W. (2002). The Statistical Sleuth: A Course in Methods of Data Analysis (2nd ed), Duxbury.

References

Ripple W.J., Johnson, D.H., Thershey, K.T. and Meslow E.C. (1991). Old–growth and Mature Forests Near Spotted Owl Nests in Western Oregon, Journal of Wildlife Management 55(2): 316–318.

Examples