Lecture 12 Flashcards
Rotation in guards appear to be linked to independent optimization of activity. How?
Heavily influenced by a nutritional status and the presence of a raised guard.
Guards inform all group members of the approach of potential predators, but guards…?
don’t appear to suffer increased risks of predation.
Learning appears to play a role in _______ behavior
guarding (difference between areas with high rates of predation vs. low)
What did Cluttonbrock say about Bednekoff’s selfish sentinel model?
Guarding may be an individual’s optimal behavior if satiated and no other individual is on guard, it might be supported, but doesn’t explain everything.
Meerkats also perform bipedal vigilance. What is that?
While foraging, individuals will stand on their hind legs and scan the area
as an increased form of vigilance. These individuals will join in producing
the ‘all clear’ signal to the group
Did females or males perform more bipedal vigilance?
Females.
T/F: Males and females spent less time foraging and eating in close proximity to pups.
true
In mixed species flocks, sentinels appear to rely on the _________ ________ abilities of the other species within the flock.
insect flushing
When an arthropod is flying away, what will a sentinel do?
will chase after it as the foraging species chases after it.
What are the steps to assessing reliability when eavesdropping?
Relevance
Discrimination
Deception
In eavesdropping, symmetric characteristics are?
-Each species is equally
reliable to the other
-Risks of predation are equal between the two species
In eavesdropping, asymmetric characteristics are?
If one species is smaller than the other, the risk of predation may be different
from the same predator
Small species find all alarms by larger species valuable, but not vice versa
Unreliable alarm calls pose a challenge to learning. Why is that?
Associative learning happens faster with a novel stimulus and a reliable consequence
Infrequently heard alarm calls are difficult to learn. Why is that?
Lack of exposure to unique alarm calls if species do not
interact often
Difficult to learn flee alarm calls versus mobbing calls (due to inherent
characteristics)
Flee alarm calls are associated with transient danger
Fairy wrens and scrub-wrens are…?
Social
vulnerable to the same threats
join mixed species flocks
Honeyeaters are?
Pair breeders
Don’t form mixed species flocks.
Fairy wrens and scrubwrens share what characteristics?
small cooperative passerines
overlapping territories.
What were the findings of Magrath’s eavesdropping study?
All three species give areal alarm calls
Fairy-wrens mean peak frequency 9.1 kHz;
Scrubwrens mean peak frequency 7.1 kHz;
Honeyeaters mean peak frequency 4.0 kHz;
Areal alarms consist of a series of similar elements rapidly
repeated
Playback of multi-element calls induce scanning and fleeing in all species
What are some characteristics of Honeyeaters?
Larger than wrens
Similar breeding seasons
Consume nectar supplemented with bugs
Feed from ground level to canopy.
What are the predators for wrens/honeyeater natural habitats?
Raptors and large avian omnivores (both groups prompt alarm calling in prey species.)
_________ ________ preys on
birds up to 25g
Collard Sparrowhawk
_______ _________ is omnivorous
and preys on eggs, nestlings,
and fledglings of all 3 species
Pied currawong
_____ __________ active
predators of small passerines
Grey butcherbirds
When recorded alarm calls were played, what were the findings?
Each species fled to cover after playback of alarm calls of conspecifics and at least 1 heterospecific call
No individuals fled to control calls
Fairy-wrens and scrubwrens were equally likely to flee to
conspecific and heterospecific alarm calls at natural amplitudes
Reduced amplitude honeyeater calls still induced fleeing
behavior in all three species, but with a slightly reduced response
What kind of alarm calls were used?
Alarm call were single element recorded at
natural spacings
single elements with high signalto-noise
ratios, minimal reverberation, and no prominent overlapping sounds
Fairy-wren and scrubwren alarm calls consisted of 4 elements; honeyeater alarms consisted of 8 elements
When did the playbacks occur?
during breeding season when these species
were not in mixed-flocks
All playbacks occurred while the focal animal was actively
foraging and no other species of bird was visible
What is the perspective on the fairy wrens from the honeyeaters?
The give false alarm calls at a high rate.
From the scrubwren’s perspective…?
both other species were
reliable
Fairy wrens and scrubwrens alerted to honeyeater calls despite what?
Despite not socializing with this species.
Honeyeaters responded to scrubwren calls ______ ________ as they
respond to conspecific calls
as reliably
Honeyeaters did not respond reliably to _______ _______ calls
fairy wren
