scholarly journals Deceptive vocal duets and multimodal display in a songbird

2017 ◽  
Vol 284 (1864) ◽  
pp. 20171774 ◽  
Author(s):  
Paweł Ręk ◽  
Robert D. Magrath

Many group-living animals cooperatively signal to defend resources, but what stops deceptive signalling to competitors about coalition strength? Cooperative-signalling species include mated pairs of birds that sing duets to defend their territory. Individuals of these species sometimes sing ‘pseudo-duets’ by mimicking their partner's contribution, but it is unknown if these songs are deceptive, or why duets are normally reliable. We studied pseudo-duets in Australian magpie-larks, Grallina cyanoleuca , and tested whether multimodal signalling constrains deception. Magpie-larks give antiphonal duets coordinated with a visual display, with each sex typically choosing a different song type within the duet. Individuals produced pseudo-duets almost exclusively during nesting when partners were apart, but the two song types were used in sequence rather than antiphonally. Strikingly, birds hid and gave no visual displays, implying deceptive suppression of information. Acoustic playbacks showed that pseudo-duets provoked the same response from residents as true duets, regardless of whether they were sequential or antiphonal, and stronger response than that to true duets consisting of a single song type. By contrast, experiments with robot models showed that songs accompanied by movements of two birds prompted stronger responses than songs accompanied by movements of one bird, irrespective of the number of song types or singers. We conclude that magpie-larks used deceptive pseudo-duets when partners were apart, and suppressed the visual display to maintain the subterfuge. We suggest that the visual component of many species' duets provides the most reliable information about the number of signallers and may have evolved to maintain honesty in duet communication.

1995 ◽  
Vol 83 (6) ◽  
pp. 1184-1193 ◽  
Author(s):  
Keerti Gurushanthaiah ◽  
Matthew B. Weinger ◽  
Carl E. Englund

Abstract Background Anesthesiologists use data presented on visual displays to monitor patients' physiologic status. Although studies in nonmedical fields have suggested differential effects on performance among display formats, few studies have examined the effect of display format on anesthesiologist monitoring performance.


1986 ◽  
Vol 30 (7) ◽  
pp. 675-678 ◽  
Author(s):  
Robert G. Eggleston ◽  
Richard A. Chechile ◽  
Rebecca N. Fleischman

An approach for measuring the cognitive complexity of visual display formats is presented. The approach involves modeling both the knowledge that can be extracted from a format and the knowledge an operator brings to a task. A semantic network formalism is developed to capture task-relevant knowledge, from which four orthogonal predictor measures of cognitive complexity are derived. In an experiment, seven different avionic missions, performed with the aid of a horizontal situation display, were studied, and three of the predictor measures were found to correlate significantly with observed task difficulty. The results indicate that a semantic network formalism can be used to produce an objective metric of format quality in terms of cognitive complexity.


Author(s):  
W. Peter Colquhoun

Using a task which closely simulated the actual output from a sonar device, the performance of 12 subjects was observed for a total of 115 hr in repeated prolonged monitoring sessions under auditory, visual, and dual-mode display conditions. Despite an underlying basic superiority of signal discriminability on the visual display, and the occurrence of long-term practice effects, detection rate was consistently and substantially higher under the auditory condition, and higher again with the dual-mode display. These results are similar to those obtained by earlier workers using artificial laboratory tasks for shorter periods, and are consistent with the notion that auditory displays have greater attention-gaining capacity in a “vigilance” situation. A further comparison of the auditory and visual displays was then made in an “alerted” situation, where the possible occurrence of a signal was indicated by a warning stimulus in the alternative sensory mode. Ten subjects were observed for a total of 57 hr in these conditions, under which performance was found to be clearly superior with the visual display. Cross-modal correlations of performance indicated the presence of a common factor of signal detectability within subjects. It was concluded that where efficiency both in the initial detection of targets and their subsequent identification and tracking are equally important, the best solution would seem to be to retain both auditory and visual displays and to ensure that these are monitored concurrently.


The Condor ◽  
2006 ◽  
Vol 108 (2) ◽  
pp. 326-335 ◽  
Author(s):  
David M. Logue

Abstract In many duet-singing songbirds, paired birds combine their song types nonrandomly to form duet songs. Several different behavioral mechanisms could generate nonrandom song type associations in duets. I tested female Black-bellied Wrens (Thryothorus fasciatoventris) for one such mechanism: adherence to a set of rules linking female response songs to male stimulus songs. I call this set of rules a “duet code.” Duets of free-living Black-bellied Wrens were recorded in 2001 and 2002. In 2003 I returned to the same territories and played the male song types from the recorded duets. Females answered male song stimuli as if duetting with the playback speaker. Although the known repertoires of females averaged 8.4 song types, each female sang only a single song type in response to each male song type. Random answering could not account for this pattern, supporting the hypothesis that females abide by duet codes. Females that were still paired with their mates from 2001–2002 answered 100% of their mate's songs with the same song types they had used previously, demonstrating that codes are stable over time. In contrast, females that were new to a territory answered an average of only 18% of their mate's song types with the same song type as the previous female, indicating that duet codes are individually distinctive. Duet participation by female Black-bellied Wrens represents a special kind of animal communication, in which discrete vocal signals consistently elicit discrete vocal responses according to an individually distinctive set of rules.


Author(s):  
Agustín J Elias-Costa ◽  
Julián Faivovich

Abstract Cascades and fast-flowing streams impose severe restrictions on acoustic communication, with loud broadband background noise hampering signal detection and recognition. In this context, diverse behavioural features, such as ultrasound production and visual displays, have arisen in the evolutionary history of torrent-dwelling amphibians. The importance of the vocal sac in multimodal communication is being increasingly recognized, and recently a new vocal sac visual display has been discovered: unilateral inflation of paired vocal sacs. In the diurnal stream-breeding Hylodidae from the Atlantic forest, where it was first described, this behaviour is likely to be enabled by a unique anatomical configuration of the vocal sacs. To assess whether other taxa share this exceptional structure, we surveyed torrent-dwelling species with paired vocal sacs across the anuran tree of life and examined the vocal sac anatomy of exemplar species across 18 families. We found striking anatomical convergence among hylodids and species of the distantly related basal ranid genera Staurois, Huia, Meristogenys and Amolops. Ancestral character state reconstruction identified three new synapomorphies for Ranidae. Furthermore, we surveyed the vocal sac configuration of other anuran species that perform visual displays and report observations on what appears to be unilateral inflation of paired vocal sacs, in Staurois guttatus – an extremely rare behaviour in anurans.


1977 ◽  
Vol 45 (3_suppl) ◽  
pp. 1171-1178
Author(s):  
R. B. Lawson ◽  
Cynthia Whitmore ◽  
Dawn Lawrence

Detection thresholds for targets displayed against two- and three-dimensional backgrounds were measured under backward masking and non-masking conditions. The results indicate that planar ring targets displayed against a two-dimensional ground are easier to mask than identical targets portrayed against a three-dimensional background. Also, the detectability of a planar ring target is enhanced when it is included within a three-dimensional rather than an identical but two-dimensional visual display. These results confirm and extend previous findings and suggest a processing asymmetry biased toward three-dimensional visual displays.


2012 ◽  
Vol 4 (2) ◽  
pp. 241-246 ◽  
Author(s):  
Vinaya Kumar Sethi ◽  
Dinesh Bhatt ◽  
Amit Kumar

This paper aims to study the structure and pattern of dawn song in a tropical avian species, the Pied Bush Chat (Saxicola caprata) in Haridwar (290 55’ N, 780 08’ E; Uttarakhand, India) in 2009. Males delivered complex dawn chorus on daily basis during only breeding season (February to July). The dawn song bout was made up of a number of distinct sections called song types. Each song type consisted of a series of similar or dissimilar units referred to as elements. Song type length averaged 1.43±0.23 sec and did not differ significantly among males. Theaverage number and types of elements in a song type were observed 8.15±1.64 and 8.01±1.56, respectively.In more than 80% of observations, song types were delivered with immediate variety and males did not follow any definite sequential pattern of song delivery. Males sang continuously for about 30 min at high rates during dawn. Males performed continuous dawn singing throughout the breeding season and seemed to interact vocally through counter-singing for extended period. Observations suggest that dawn song delivery in Pied Bush Chat plays an important role in maintenance and adjustment of social relationship among neighbouring males.


2019 ◽  
Vol 28 (2) ◽  
pp. 181-186
Author(s):  
Rochishnu Dutta ◽  
Manjunatha Reddy ◽  
Tom Tregenza

The bush cricket Mecopoda elongata provides a striking example of sympatric intraspecific divergence in mating signals. Five completely distinct song types are found in various parapatric and sympatric locations in South India. While there is convincing evidence that population divergence in M. elongata is being maintained as a result of divergence in acoustic signals, cuticular chemical profiles, and genital characters, the causes of the evolution of such divergence in the first place are unknown. We describe the discovery of a tachinid parasitoid with an orthopteroid hearing mechanism affecting M. elongata. This parasitoid may have a role in driving the extraordinary divergence that had occurred among M. elongata song types. Over two years we sampled individuals of three sympatric song types in the wild and retained individuals in captivity to reveal rates of parasitization. We found that all three song types were infected with the parasitoid but that there were significant differences among song types in their probability of being infected. The probability of tachinid parasitization also differed between the two sampling periods. Therefore, it is possible that parasitoid infection plays a role in song type divergence among sympatric bush cricket populations.


Sign in / Sign up

Export Citation Format

Share Document