DOI: 10.5061/dryad.2hf15
title: Data from: Alarm calls of a cooperative bird are referential and elicit context-specific antipredator behavior

description: Although functionally referential signals have been extensively studied,
 largely in mammals (e.g., nonhuman primates, see Cheney and Seyfarth
 (1988); mongooses, see Manser et al. (2002); and other ground-dwelling
 species, see Blumstein and Armitage (1997), other social taxa such as
 birds would similarly benefit from the use of referential signals. We
 therefore investigated alarm calling in the cooperative noisy miner
 (Manorina melanocephala), a species that has been anecdotally recorded
 producing aerial alarms to flying predators and empirically recorded
 generating terrestrial alarms to ground-based threats. For these signals
 to be truly referential however, they must meet 3 criteria. First, calls
 must be structurally distinct, a requirement that these 2 call types meet.
 Second, calls must be stimulus-specific and reliably associated with a
 given stimulus. We tested this on free-living birds by exposing them to a
 simulated aerial predator that was either in flight or subsequently
 perched and thus presented one of the first studies on functionally
 referential alarm systems where both aerial and terrestrial alarm calls
 have been tested. Miners only produced aerial alarms while the stimulus
 was in flight, switching to terrestrial alarms once it landed. Third,
 referential signals must elicit different escape responses that are
 “appropriate” to the associated threat. Under field conditions, aerial
 alarm playback alone provoked an almost instantaneous response of fleeing
 to vegetation cover, whereas terrestrial alarm playback elicited
 significantly slower responses by receivers and an increase in scanning
 behavior. During laboratory experiments, aerial alarms stimulated birds to
 spend more time looking upwards, whereas terrestrial alarm calls
 stimulated individuals to scan perpendicularly, as expected if these
 stimuli provided information on likely predator location. Although other
 avian taxa have been shown to use referential alarm signals, this system
 provides novel evidence of referential calls based on the behavior rather
 than the type of predator, providing a highly adaptive means of
 communicating risk to other members of the social group in this
 cooperative species.
description: Experiment One: Are the
 type of alarm signals produced stimulus-specific?Presentation of a
 stimulus similar to a gliding raptor established a direct association
 between aerial stimuli and aerial alarm call production by noisy
 miners.Exp
 1 data.xlsxExperiment Two: Does
 receiver flight response alter between alarm call types?In the second field
 test, noisy miners demonstrated the ability to alter their behavior
 according to changes in the alarm call type broadcast.Experiment
 2.csvExperiment Three: Does
 receiver observational response differ between alarm call
 types?Birds were then tested
 in standardized conditions and demonstrated the ability to alter their
 behavior in the 20 seconds post-playback as expected under a referential
 signaling communication system.Experiment
 3.csv