|Description||The problem. The objective of the study was to
develop a technique of estimating large numbers of geese accurately and to provide a permanent reproducible record of the estimate. The technique to be developed was to utilize equipment easily available to field personnel.
Procedure. The red, blue, green, and infra-red
electromagnetic wave lengths were examined for use in the technique. The band providing the maximum contrast between the geese and the natural background was analyzed to determine
the accuracy and reproducibility of estimated goose numbers.
Findings. The blue color band should be used when
aerial photography is used to count geese. Count estimates obtained with the Digacol Model 4010 density analyzer (Iowa Geological Survey Remote Sensing Lab.) did not have the accuracy desired. When the photo negatives were changed to
positives and enlarged, the accuracy improved to acceptable limits.
Conclusions. The techniques developed included:
using a blue pass filter (Kodak 47 B), verticle aerial photography, photographing resting on a uniform background (preferably water) at an altitude where the geese are not disturbed but can be photographed easily, and finding that
easily available equipment can be used to estimate large numbers of geese. Finding the limitations of the density analyzing equipment available lead to the acknowledgement that machinery does exist that can use the photographs to count geese.
Recommendations. A method for photographing geese
has been developed however estimating goose numbers by density analyzing is dependent upon the availability and sophistication of the equipment. For reproducible accurate count
estimates, photographs and negatives should be submitted to the EROS Data Center, Sioux Falls, South Dakota.||en