ts of its
regular home range). In any case the rat may find it necessary to
traverse an additional area in order to reach the food source. This may
involve, in part, extension vertically, as when the rat obtains food
from trees directly over the house. The home range is thus somewhat
three-dimensional; both trails and feeding places are often above
ground. Because of dependency on cover, woodrats do not forage randomly
in all directions from the house.

Although the house and its immediate environs are defended as a
territory by the occupant, possession may be soon relinquished. A
woodrat may shift frequently from one house to another, especially if
unoccupied houses are readily available. Because woodrats had undergone
drastic reduction in numbers, as discussed on p. 505, unoccupied houses
in various stages of disrepair were numerous throughout the woodland in
1948 and 1949, and the rats that were present then seemed especially
inclined to wander. Even old houses that are collapsed and
disintegrating may be used temporarily, or may be taken over and
repaired. Houses that are in sites exceptionally favorable in that they
provide food and shelter may be occupied more or less permanently, with
a succession of woodrats over many generations.

Shifts to new areas are perhaps most often motivated by a search for
mates. Such shifts are, on the average, longer and more frequent in
males. Males must range farther in search of females when numbers are
low. On the other hand, when numbers are high and most of the best sites
are occupied, newly independent young and displaced adults are forced to
travel greater distances in search of homes. Some of the larger and more
powerful males move far greater distances than smaller males. The
longest distances recorded were mostly for large adult males in breeding
condition. The average maximum distance between successive points of
capture for 27 adult males was 345 feet. For 39 females (adults and
subadults) the corresponding figure was 143 feet. The extremes for males
were 0 to 1080 feet and for females, 0 to 650 feet. Of the 27 males,
five moved the maximum distance in a single night. Most of the long
movements by males did not constitute clear-cut shifts in home range,
and many returned to their original locations.

The average distance between points of first and last captures for 72
subadult and adult males was 165 feet. A similar figure for 72 subadult
and adult females was 133 fe