SR14: Flower 2014-deception by alarm mimicry in drongos Flashcards
deception is common but what will victims do if they are produced too often?
discriminate against it and ignore it
what was the study species?
fork tailed drongos
what do the drongos do that could be considered a deceptive signal?
use false mimic alarm calls to scare species away from the food so they can steal it
if the alarm call is repeated what will the target species do?
reduce its response
why will the drongo change its alarm call type when making repeat theft attempts on a species?
to maintain the fear response and avoid frequency dependent constraints
what happens as signal frequency increases?
individual success declines
how many wild drongos were looked at?
64
how long do the dongos spend following target species and give 2 examples
over 1/4 of their time
southern pied babblers
meerkats
when predators approach what is produced and what does this allow for?
true alarm calls
allows for the target species to flee in cover and increase their foraging returns
when target individuals find large food items what may drongos do?
produce false alarm calls so the target flees and it can steal the food
if drongos had failed their previous food theft attempt what were they likely to do the following time?
change their false alarm call
what % of biomass intake does food theft account for?
23%
in terms of number of different calls what did the repertoires range from?
9-32 different calls
how many different false alarm call types were recorded and of these how many were drongo specific and how many mimic other species?
51
6 drongo specific
45 mimic
in what % of false alarms were mimic calls?
42%
what was the experimental procedure on pied babblers? (4)
- 4 different call types at 20 min intervals
- control non alarm, drongo alarm, mimicked starling, mimic pied babbler
- measured response time for them to stop handling food
- slower response to resume foraging with mimic calls
what did the babblers do when:
a) the same alarm call was played 3 times
b) if the third call was different
a) decreased response
b) maintained response
when observing food theft attempts on 151 occasions what was found after failed food theft attempt?
call type changed
over time what may happen to the deceived species?
may habituate to all deceptive signals
