02965nas a2200277 4500008004100000022001300041245012000054210006900174260001600243300001200259490000800271520192300279653002202202653001802224653002502242653001602267653002402283653002202307653001402329100002202343700002402365700002302389700002002412700002202432856023302454 2018 eng d a0003347200aBarn owl nestlings vocally escalate when interrupted by a sibling: evidence from an interactive playback experiment0 aBarn owl nestlings vocally escalate when interrupted by a siblin cJan-11-2018 a51 - 570 v1453 a

To resolve conflicts of interest, animals can vocally signal their resource-holding potential and motivation to compete. This allows conspecifics to adjust their behaviour to each other without fighting physically. Making sure that competitors correctly assess each other's vocal information requires mechanisms to prevent signal interference. Alternating calls with those of an opponent (i.e. waiting until the opponent's call has ended before starting to vocalize) is widely observed in animals and could be partly acquired through learning. Regardless of whether competitors interrupt conspecifics as a signal of dominance or by accident, the information transferred by the interrupted individual is likely to be partly blurred. Interrupted individuals would hence benefit from counterattacking by calling more intensely, indicating to their competitors that calling simultaneously is counterproductive. We tested this ‘social feedback’ hypothesis in the barn owl, Tyto alba, in which young siblings negotiate vocally over which individual will have priority access to the next food item delivered. It has already been shown that nestlings actively avoid interrupting each other, but it remains untested whether nestlings give social feedback when interrupted. To test this, we developed an ‘automated interactive playback’ which broadcast calls that either interrupted or did not interrupt the calls of a singleton nestling. When a playback call interrupted a nestling, this individual immediately intensified vocal communication by quickly producing a long call and by producing more calls. As previously shown, this reaction tends to silence competitors and thereby increases the individual's likelihood of obtaining the next food item. Such social feedback could reinforce the evolutionary stability of vocal sibling negotiation as a nonaggressive way to share food.

10aauditory feedback10acommunication10ainteractive playback10aoverlapping10asibling negotiation10atemporal dynamics10aTyto alba1 aDucouret, Pauline1 aDreiss, Amélie, N.1 aGémard, Charlène1 aFalourd, Xavier1 aRoulin, Alexandre uhttps://linkinghub.elsevier.com/retrieve/pii/S0003347218302732https://api.elsevier.com/content/article/PII:S0003347218302732?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0003347218302732?httpAccept=text/plain02246nas a2200349 4500008004100000245010300041210006900144260001600213300001400229490000800243520124400251653001401495653001401509653001201523653001801535653001601553653002101569653001601590653001401606100002401620700002201644700002601666700002201692700002201714700002001736700002301756700001801779700001901797700002201816700001501838856004301853 2017 eng d00aNo need to shout: Effect of signal loudness on sibling communication in barn owls Tyto alba0 aNo need to shout Effect of signal loudness on sibling communicat cJan-06-2017 a419 - 4240 v1233 a

In animal communication, signal loudness is often ignored and seldom measured. We used a playback experiment to examine the role of vocal loudness (i.e., sound pressure level) in sibling to sibling communication of nestling barn owls Tyto alba. In this species, siblings vocally negotiate among each other for priority access to parental food resources. Call rate and call duration play key roles in this vocal communication system, with the most vocal nestlings deterring their siblings from competing for access to the food item next delivered by parents. Here, we broadcast calls at different loudness levels and call rate to live nestlings. The loudness of playback calls did not affect owlets' investment in call rate, call duration or call loudness. The rate at which playback calls were broadcast affected owlets' call rate but did not influence their response in terms of loudness. This suggests that selection for producing loud signals may be weak in this species, as loud calls may attract predators. Moreover, given that owlets do not overlap their calls and that they communicate to nearby siblings in the silence of the night, loud signals may not be necessary to convey reliable information about food need.

10aacoustics10aamplitude10abegging10acommunication10acompetition10amultiple signals10anegotiation10aplaybacks1 aDreiss, Amélie, N.1 aDucouret, Pauline1 aRuppli, Charlène, A.1 aRossier, Virginie1 aHernandez, Lucile1 aFalourd, Xavier1 aMarmaroli, Patrick1 aCazau, Dorian1 aLissek, Hervé1 aRoulin, Alexandre1 aFusani, L. uhttp://doi.wiley.com/10.1111/eth.12612