Line Transect

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Hayne's Estimator

The Hayne estimator was develop to estimate density of birds that flush as an observer comes within a certain radius.  This method assumes that there is a fixed flushing distance r  and all animals within r distance of the observer will flush.

The density is estimated by :

where:

D_H is the Hayne density estimate
n is the number of animals
L is the length of the transect
r_i is the sighting distance to the ith animal.
 

R is the mean of the reciprocal of the sighing distances and is calculated as:

The variance of the density estimate is calculated as :

where:

D_H is the Hayne density estimate

n is the number of animals

var(n) is the variance of n approximately equal to n

r_i is the sighting distance to the ith animal.

 

Hayne method assumed that the mean sighing angle is 32.7^o.  This can be tested by:

Z is the standard normal deviate test value
n is the number of animals sighted
Theta is the mean observed sighting angle (Figure 1).
 

The test would be if the Z value is greater than 1.96 or less than -1.96 the sighting angle is statistically different than 32.7^o at the alpha = 0.05 level.

Also See:

Krebs, C. J. 1989. Ecological Methodology. Harper and Row, Publishers. New York. 654 pp.