Geoscience Reference
In-Depth Information
Territories
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A territory is an area within an animal's home range over which the animal has
exclusive use, or perhaps priority use. A territory may be the animal's entire
home range or it may be only part of the animal's home range (its core, for
example). Territories may be defended with tooth and claw (or beaks, talons,
or mandibles) but generally are defended through scent marking, calls, or dis-
plays (Kruuk 1972, 1989; Peters and Mech 1975; Price et al. 1990; Smith
1968), which are safer, more economical, and evolutionarily stable (Lewis and
Murray 1993; Maynard Smith 1976). Members of many species, such as red
squirrels (
Tamiasciurus hudsonicus;
Smith 1968), defend individual territories
against all conspecifics, but tremendous variation in territorial behavior exists.
In some species, individuals defend territories only against members of the
same sex. In other species, mated pairs defend territories. In still other species,
extended family groups, sometimes containing non-family members, defend
territories. Whether territories are defended by an individual, mated pair, or
family appears to depend on the productivity, predictability, and fine-grained
versus coarse-grained patchiness of the limiting resources (Bekoff and Wells
1981; Doncaster and Macdonald 1992; Kruuk and Parish 1982; Macdonald
1981, 1983; Macdonald and Carr 1989; Powell 1989).
Members of many species in the Carnivora exhibit intrasexual territoriality
and maintain territories only with regard to members of their own sex (Powell
1979, 1994; Rogers 1977, 1987). These species exhibit large sexual dimor-
phism in body size and males of these species are polygynous (and females un-
doubtedly selectively polyandrous). Females raise young without help from
males and the large body sizes of males may be considered a cost of reproduc-
tion (Seaman 1993). For species that affect food supplies mostly through
resource depression (i.e., have rapidly renewing food resources such as ripen-
ing berries and nuts or prey on animals that become wary when they perceive
a predator and later relax), intrasexual territoriality appears to have a minor
cost compared to intersexual territoriality because the limiting resource
renews. This cost may be imposed on females by males (Powell 1993a, 1994).
Males of many songbird species defend territories. In migratory species, the
males usually establish their territories on the breeding range before the females
arrive and a male will continue to defend his territory if his mate is lost early in
the breeding season. For these territories, the limiting resource may be a com-
plex mix of the food and other resources that females need for successful repro-
duction and the females themselves. In red-cockaded woodpeckers (
Picoides
