SREL Reprint #0001




Measurement of Territory and Home Range Size in Birds

E. P. Odum and E. J. Kuenzler

It is suggested that the distinction between maximum territory (defended area) or home range (in case area is not defended) and utilized territory or home range simplifies the problem of quantitative measurement.

When observed size of the occupied area was plotted against the number of observations made at 5-minute intervals, characteristic “observation-area” curves were obtained (figures 1 and 2), which can be used to standardize measurement of size.  The one percent level on the smoothed curve is suggested as a suitable point to use in comparisons; it is arbitrary but represents a point of diminishing returns, is independent of the total number of observations on the size of the territory, and is comparable regardless of species or stage of the breeding cycle.

The use of the observation-area curve is illustrated by a comparison of territory size at successive stages in the nesting cycle of the same pair (table 1) and at the same nesting stage in different individuals (table 2).

An alternate procedure, that of expressing territory size in terms of an activity radius, is tested employing the method used by Dice and Clark in a study of home range in deermice.  The frequency polygons for Chipping Sparrows and Kingbirds were essentially normal but exhibited platykurtosis which is interpreted to mean that territorial birds, in contrast to mice, are relatively fixed in their movements during a given phase of the nesting cycle.  Therefore, the expression of territory size in terms of area and the use of the observation-area curve are justified.

SREL Reprint #0001

Odum, E.P. and E.J. Kuenzler. 1955. Measurement of territory and home range size in birds. Auk 72:128 137.


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