I.C. Behavioral Ecology. Definition: How an individual animal’s behavior interacts with its environment to affect its survival and reproduction. Foraging ecology (also falls under physiological ecology, e.g., energy acquisition) Territoriality Mating systems.
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Smaller animals can travel over more of their home range in one day compared to larger animals.
Linear measure of distance
Something to do with scaling and energy requirements
Terrestrial herbivores (mammals)
Terrestrial carnivores (mammals)
Terrestrial carnivores (birds)
Higher trophic level needs more space, why?
Haskell et al. 2002
Feeding on nectar
Nests, defense of nest sites by both males and females
Territory holder survival
Benefits of territories compared to no territories
Biomass, productivity higher; Feeding rate higher
More reproduction and more successful reproduction
More offspring survived in territories, with guarding parent
Shelter holes limited, survival increased in territories
(other costs than time)
Costs of territories compared to no territories
More time spent fighting
Lower liver glycogen; fighting activities use more energy than non-fighting activities
More injuries to fins and scales in territory holders
Territory holders lost weight during defense
When animals are defending and competing for space, they become evenly dispersed in the environment.
Gannet, seabirds nest on rocky cliffs on sea coasts
See gannet colony movie on the EVE 101 web site
Clumped resources or benefit to togetherness
No interactions among individuals
A male Red-winged Blackbird displaying on his breeding territory in a marsh
Red-winged blackbird territorial song
Female red-winged blackbird
Nest of red-winged blackbird
Good nest sites that attract females to the territory
Benefit (can’t use it all)
Cost or Benefit
Prediction: this “optimal” size is the predicted size of territories in the real world, given these costs and benefits.
Costs exceed benefits here
Net benefits are maximum here
= optimal territory size
A simple economic model
Costs or benefits
Size at which costs exceed benefits
Territory size (m2)
When food is added to a territory experimentally, the territory holder adjusts the size of the area defended. Why?
Males have bigger territories than females for a given prey abundance: Why?
Territory size (cm2) =
Distance an intruder is chased
Investment in offspring after the gamete stage is related to the mating system
Tradeoff: mates v care of young
Number of mates for each sex:
Two examples illustrating how ecological conditions determine the mating system
Resource defense polygyny:
Males defend resources to attract as many mates as possible
Resources are not defensible so males compete for the opportunity to mate
Male red-winged blackbird displaying with the flash of the wings and a song. This display is intended to advertise his territorial boundaries to other males. This type of display lowers the cost of defense. Why?
The birds accommodate human altered habitats easily, using irrigation ditches as territories, and displaying from fences and telephone wires.
They choose a place they like to settle down. What conditions are they looking for?
See movie of parents feeding offspring on the EVE 101 web site
Parents continue to feed the fledgling for several weeks until it is “weaned”.
Nestling stuffing itself with dragonfly abdomens brought by the parent.
Is this play? Couldn’t the male get seriously hurt? Why bother with a heron?
1 f/terr.2 ff/terr.3 ff/terr.
Males with variable territories
A B C D
Extreme polygyny: Leks
Capercaille (grouse) UK
Males 200% size of females by weight
Gray Partridge (Europe)
Males and females the same size
See manakin movies on EVE 101 web site
Lek mating systemTerritoriality defending opportunity to mate (no resources)Resources are too scarce to be defensible; female home range very large
See grouse movie on EVE 101 website