Detections of pronghorn from fixed-wing aerial surveys in Southeastern
Wyoming using four angular bins defined by strut marks. Illustrates data
where altitude above ground level (AGL) varies during the survey.
Format
A data frame with 660 observations on the following 5 variables.
STRATUM
a numeric vector
direction
a factor with levels NS
representing the survey direction
AGL
height above ground
level
Band
a factor with levels ABCD which represent angular bands between breaks at
35.42,44.56,51.52,61.02,70.97 degrees. These angles were set based on
selected distance bins based on the target AGL.
cluster
number of pronghorn in the observed cluster
Details
Each record is an observed cluster of pronghorn. The data provide the
stratum for the observation, the direction of travel, the AGL at the time of
the observation, the angular bin which contained the center of the pronghorn
cluster(group), and the number of pronghorn in the group. The angular bins
were defined by a combination of two window and five wing strut marks to
define bin cutpoints for perpendicular ground distances of 0-65, 65-90,
90-115, 115-165 and 165-265 meters when the plane is 300' (91.4 meters)
above ground level. The inner band is considered a blind region due to
obstruction of view beneath the plane; thus th the line is offset 65 meters
from underneath the plane.
Source
Data provided courtesy of Rich Guenzel of Wyoming Game and Fish.
References
Laake, J., R. J. Guenzel, J. L. Bengtson, P. Boveng, M. Cameron,
and M. B. Hanson. 2008. Coping with variation in aerial survey protocol
for line-transect sampling. Wildlife Research 35:289-298.