Introduction to Behavioural Ecology

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Introduction to Behavioural Ecology

• Lecture 5

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Behavioural Ecology

• Study of individual animals
• Their interactions with the environment
• Including their interactions with
• Conspecifics
• Predators
• Parasites
• Prey
• Etc.

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Behavioural Ecology

• Can provide important insight for the restoration
  or management of populations
• Examples
• Learning in animals reared in captivity
• Both failure to learn behaviours required for the
  wild
• And learning inappropriate behaviours in
  captivity
• Maintenance of genetic variation
• Need to understand mating systems

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Behavioural Ecology

• Population data may be misleading
• Places where animals are most abundant may not be
  the habitat feature that is limiting population
  growth

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Behavioural Ecology

• Directing restoration or management at the wrong
  stage may not be effective
• e.g. yellow perch
• Preserving genetic variation
• Rare behaviours (genotypes) are important to
  preserve
• Maintains the populations capacity to adapt

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Behavioural Ecology

• Much of the early behavioural ecology focused on
  proximate causes of behaviour
• This continued long after Darwin proposed his
  theory of evolution by natural selection
• Recent efforts have shifted toward looking for
  ultimate evolutionary causes

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Behavioural Ecology

• Animals face numerous behavioural decisions which
  they must make each day

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Behavioural Ecology

• Whether to
• feed or remain at the roost
• Defend young or flee
• When to migrate
• Where to roost
• Where to feed

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Behavioural Ecology

• Many decisions involve trade-offs
• Investing in territorial defence means less time
  to feed, mate etc.
• Decisions will influence an animals fitness

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Behavioural Ecology

• Decisions may be conscious or evolutionary
  decisions
• The idea that animals make conscious decisions
  has been controversial

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Early behavioural studies

• Focused on proximate explanations of behaviour
• Early ethologists divided behaviours into two
  categories
• Learned
• Instinctive

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Learned behaviours

• Acquired or modified through experience

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Instinctive behaviours

• Genetically programmed
• Hard wired into the animals nervous system
• They are not modified by an animals experience

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Learned behaviours

• Young blue jay feeding on a monarch butterfly
• After experiencing the distasteful prey the blue
  jay learns to avoid monarchs

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Instinctive behaviour

• Heat avoidance reflex in humans
• Many parental instincts in birds

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Instinctive behaviour

• Niko Tinbergen
• Feeding instincts in Herring gulls
• Nestlings instinctively know to peck at the
  parents bill spot
• Will peck at anything long with a red spot

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Instinctive behaviour

• Greylag geese
• Retrieve stray eggs with a characteristic
  behaviour
• Perfectly executed the first time it is used

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Instinctive behaviour

• We call these behaviours that are characterized
  by highly stereotyped patters
• Fixed Action Patterns (FAP)

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Fixed Action Patterns

• Stimulus that initiates the FAP is called a
  releaser
• Red spot on the bill of a herring gull is the
  releaser
• Once FAP behaviour is released it is difficult to
  stop (Greylag goose will continue to gather an
  egg that has been removed midway through the FAP)

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Fixed Action Patterns

• Some species exploit the FAPs of other species
• Rove beetles exploit the parental behaviour of
  ants
• Rove beetles release a pheromone that releases
  the brooding instinct of the ants
• The ants take care of the beetle larvae which
  then eat the eggs of the ants

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Supernormal stimulus

• Cowbirds
• Nest parasites
• Eggs and nestlings are large
• Provide supernormal stimulus
• Elicits parental behavior of parents

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Learned behaviours

• Russian Psychologist Ivan Pavlov
• Salivation response of dogs

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Pavlov
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Pavlov
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Conditioned response

• After several trials with the paired stimuli
• Bell and meat
• Bell alone induces salivation response
• Classical conditioning

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Operant conditioning

• B.F. Skinner Skinner box
• Rat placed in a box with a lever that controls a
  food dispenser
• Learns that pressing leaver leads to food reward
• Rat is operantly conditioned to press the lever

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Skinner box
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Learned and instinctive behaviour

• May sometimes be difficult to separate
• In many cases behaviours have both learned and
  genetic (instinctive) components

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Australian Parrots

• Both species live in eucalyptus forest
• Both nest in tree cavities
• Both parrots lay one egg per day and only begin
  incubation after the clutch of eggs is complete

Galah
Pink Cockatoo
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Australian Parrots

• Because it takes 3-4 days to complete clutch both
  species can lay eggs in the same cavity without
  much interaction
• Conflict arises when incubation begins
• The larger Pink Cockatoo has the advantage and
  evicts the smaller Galah

Galah
Pink Cockatoo
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Australian Parrots

• The Pink Cockatoo will often raise both its own
  young and the Galahs offspring

Pink Cockatoo
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Rowley and Chapman

• Compared the behaviour of Galahs that were
  raised by their own parents to the Galahs that
  were cross-fostered
• Question do cross-fostered Galahs behave like
  Pink Cockatoos or Galahs?

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Rowley and Chapman

• Answer It depends on the behaviour
• Begging calls and alarm calls are typical Galah
  calls
• Contact calls, wingbeat frequency, food choices
  resemble Pink Cockatoo behaviour

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Nest location by digger wasps

• Use location of landmarks to find their nests

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Nest location by digger wasps

• Use location of landmarks to find their nests

Nest Location
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Food caching behaviour

• Many species store food during times of food
  abundance
• Retrieve it when food is scarce
• Examples Birds chickadees
• nutcrackers
• Mammals squirrels
• hamsters

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Food caching behaviour

• How do these animals retrieve the stored food
• Hypotheses
• Randomly search the general area
• Look for patches that look recently disturbed
• Remember exactly where they put the food

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Chickadees

• Store hundreds of bits of food

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Sherry, Shettleworth and others

• Placed chickadees in aviaries
• Stored food in hiding places provided
• Stored food was not visible (under Velcro tabs)

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Monitored birds searching behaviour

• Birds did not search randomly
• Went to sites where they had stored food
• Rarely revisited sites from which they had stored
  and then removed food

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Clarks Nutcracker
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Clarks Nutcracker

• Store up to 9000 food items
• Pine seeds (1-10 seeds per cache)
• Stored over an entire hillside

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Clarks Nutcracker

• Store seeds in holes that they dig
• Store seeds in the fall and retrieve them months
  later

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Clarks Nutcracker

• Aviary experiments
• Birds allowed to store seeds
• Seeds then removed and aviary swept clean
• Compared search patterns to map of where the
  seeds were stored
• Birds dug in former cache sites 80 of the time

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Tool use once though to be activity exclusive to
humans

• We now know it is wide spread
• Non-human primates
• Birds
• insects

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Tool use

• Chimps will use sticks to extract termites from
  termite mounds
• Some birds will do the same to obtain termites,
  ants and other insects

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Leafcutter Ants

• Will use leaves to mop up sticky food sources

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Leafcutter Ants

• Fungus gardens

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Observational learning

• Inexperienced observers in many species will
  learn tasks more quickly after observing others
  perform the task correctly
• e.g., young big brown bats that observe
  experienced bats get food by navigating an
  obstacle course take fewer tries to succeed
  themselves
• In starlings observing failure results in
  better learning than observing success

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Some applications of learning

• Training captive animals to avoid predators
• Lack of predator avoidance is one of the main
  reasons for failed reintroduction attempts
• Also need to avoid the learning of inappropriate
  behaviours while in captivity