members of the younger cohort. In other cases, younger individuals in poor habitat
forgo breeding altogether, gambling instead on inheriting a good territory at a later
date. A good example of this is the Seychelles brush warbler (Bebrornis seychellensis),
in which many youngsters choose to stay at the nest and help their parents rear
siblings rather than set off on their own (Komdeur 1992, 1993). Like all inheritances,
this can be a risky proposition, because it depends on the probability that the helper
survives and the (hopefully lower) probability that the current occupant does not.
Economic models predict that such helping behavior will be selected for when there
are pronounced disparities in the quality of potential breeding sites and where the
probability of long life is reasonably good. The Seychelles warblers proved this point
by abandoning helping behavior as soon as openings for good territories were created.
Territoriality can play a stabilizing role on population dynamics (Fryxell and Lundberg
1997). If there is an upper limit on the number of territories that can be supported,
this can effectively cap breeding by the predator population, preventing large-scale
predator–prey cycles of the sort described in Chapter 12. Since many top carnivores
are territorial (e.g. wolves, weasels, lions, hyenas, and tigers), this suggests that a
deeper understanding of carnivore territory formation and dynamics in relation to
changes in abundance of both predators and prey is essential to adequate conserva-
tion and management efforts.Foraging success is strongly affected by behavioral decisions of both predators and
their prey. We consider a number of these decisions. First, foragers must decide which
prey to attack and which to ignore. Optimal diet choice theory can be used to
determine wise solutions to this problem, based on the opportunity cost of wasting
time on poor prey in hand while better prey might yet still be found. For herbivores,
foraging decisions are shaped by multiple constraints, such as balancing the need to
meet requirements for a scarce nutrient with the objective of maximizing energy intake.
Such problems can be approached using linear programming. Optimal patch depar-
ture theory is useful in considering how long foragers should stay in a particular area
before moving on. The best theoretical solution is that animals be sensitive to the
opportunity cost of wasting time in a poor patch, when a better patch lies close
at hand. As for diet, herbivores choose patches in a manner that balances multiple
constraints on their feeding.
Patch preferences can also be shaped by the need to trade off risk of predation
against foraging gains. Risk-sensitive foraging demands complex approaches to
decision evaluation, such as dynamic state variable modeling. Measurement of
habitat-specific preferences demands special statistical tools, such as resource selec-
tion functions.
We also consider how social processes influence foraging decisions. Fitness is likely
to decline as population density in preferred habitats grows, necessitating expansion
of the population into poorer areas. Social interference plays an important role
in this process, and we show how interference and territoriality can be viewed as
adaptive responses to environmental conditions. All these behaviors have important
consequences for the dynamics of wildlife populations.THE ECOLOGY OF BEHAVIOR 77
5.7 Summary
WECC05 18/08/2005 14:42 Page 77