05392nas a2200265 4500008004100000245008800041210006900129520457700198653002404775653002704799653000904826653001304835653002504848653002804873653001904901653002104920653002704941653001304968653001804981653002404999653001505023653001505038100003205053856004105085 2020 eng d00aDivergent selection and reproductive isolation: an empirical study on reed buntings0 aDivergent selection and reproductive isolation an empirical stud3 a

Divergent selection and local adaptation are responsible for many phenotypic differences between populations, potentially leading to speciation through the evolution of reproductive barriers. Acoustic divergence, in particular, is often the basis of assortative mating and behavioral isolation in birds. However, some species have different singing styles used in distinct social contexts, and songs of each style may change at different rates over time and space. Mate recognition largely depends on learning, generally resulting in discrimination against nonlocal stimuli. Nevertheless, there may also be geographical variation in discrimination, allowing inference on the mechanisms behind recognition. Morphologic divergence can cause reproductive isolation too, and a strong association between bill traits and foraging niche, at a given place and time, may indicate ecological speciation is at play and how.
This thesis focused on reed buntings (Emberiza schoeniclus), a small passerine that breeds in marshlands throughout the Palearctic. Populations of three subspecies were studied: migratory E. s. schoeniclus, breeding in northern and central Europe; and the residents E. s. lusitanica from northwest Iberia and E. s. witherbyi from southeast Iberia and southern France (hereafter schoeniclus, lusitanica and witherbyi, respectively).
Four main objectives were addressed using different approaches: (1) phenotypic divergence was evaluated to determine the extent of local adaptation to migration and diet, using linear measurements and geometric morphometrics; (2) song divergence between subspecies and between the three singing styles of each subspecies were tested searching for effects of sexual selection, using spectral traits and derived synthetic variables; (3) song discrimination level was determined to infer premating reproductive isolation, using playback of fast song to test territorial males; (4) association between bill morphology and foraging niche was evaluated searching for evidence of natural selection, by sampling blood in southwest Europe during the winter (when target subspecies co-occur) and performing stable isotope analyses (carbon and nitrogen).
As predicted, migratory subspecies were smaller and had longer and more pointed wings. Unexpectedly, their tail was longer, probably due to correlation with wing length. witherbyi, which feed on insects hiding inside reed stems during the winter, had a very thick bill; whereas schoeniclus, which feed on seeds, had thinner bills. Although smaller, lusitanica had thicker and longer bill than schoeniclus. Geometric morphometrics revealed that southern subspecies have a more convex culmen than schoeniclus, and that lusitanica and schoeniclus bills differ more in shape than in linear measurements. The two singing styles under sexual selection (dawn and fast songs, related to obtaining extrapair and social mates, respectively) diverged more than the slow songs (an all-clear signal to nest attending females). Multiple song traits differed between subspecies in all styles, with intermediate values for lusitanica. Cluster analyses of populations indicate that sexually selected styles better discriminate subspecies, describing a major split in song features between schoeniclus and the resident subspecies. It was found that witherbyi, and to some extent lusitanica, males largely ignored schoeniclus songs. However, witherbyi reacted less strongly to lusitanica than the converse. In contrast, schoeniclus males reacted equally strongly to all subspecies. schoeniclus showed a broader isotopic niche than southern subspecies, which seemed similar despite witherbyi more divergent bill. Stable isotope ratios were consistent with resident subspecies feeding on C3-plant-feeding insects, whereas schoeniclus diet also included C4 plant material.

Subspecies differing in several traits as theoretically predicted indicate local adaptation through natural selection. Greater song divergence in fast and dawn styles implies that sexual selection is important in this evolutionary process. Differential territorial defense provides evidence of premating reproductive isolation, and discrimination by southern subspecies seems associated with local adaptation. Recognition pattern agrees with ecological rather than neutral divergence, as predicted in ecological speciation processes. Isotopic niche divergence between northern and southern subspecies suggests that bill differentiated by natural selection through competition during winter.

10aacoustic divergence10aasymmetric recognition10abill10abirdsong10aEmberiza schoeniclus10ageometric morphometrics10aisotopic niche10alocal adaptation10amorphologic divergence10aplayback10asinging style10asong discrimination10aspeciation10asubspecies1 aGordinho, Luís, de Oliveir uhttps://bio.acousti.ca/fi/node/5819802298nas a2200241 4500008004100000022001300041245009500054210006900149260001600218300001100234490000800245520154100253653002501794653001301819653002901832653002001861653001601881100002401897700001801921700002801939700002201967856006701989 2020 eng d a0003682X00aA two-stage approach to automatically detect and classify woodpecker (Fam. Picidae) sounds0 atwostage approach to automatically detect and classify woodpecke cJan-09-2020 a1073120 v1663 a

Inventorying and monitoring which bird species inhabit a specific area give rich and reliable information regarding its conservation status and other meaningful biological parameters. Typically, this surveying process is carried out manually by ornithologists and birdwatchers who spend long periods of time in the areas of interest trying to identify which species occur. Such methodology is based on the experts’ own knowledge, experience, visualization and hearing skills, which results in an expensive, subjective and error prone process. The purpose of this paper is to present a computing friendly system able to automatically detect and classify woodpecker acoustic signals from a real-world environment. More specifically, the proposed architecture features a two-stage Learning Classifier System that uses (1) Mel Frequency Cepstral Coefficients and Zero Crossing Rate to detect bird sounds over environmental noise, and (2) Linear Predictive Cepstral Coefficients, Perceptual Linear Predictive Coefficients and Mel Frequency Cepstral Coefficients to identify the bird species and sound type (i.e., vocal sounds such as advertising calls, excitement calls, call notes and drumming events) associated to that bird sound. Conducted experiments over a data set of the known woodpeckers species belonging to the Picidae family that live in the Iberian peninsula have resulted in an overall accuracy of 94,02%, which endorses the feasibility of this proposal and encourage practitioners to work toward this direction.

10aAudio classification10abirdsong10aBirdsound classification10aevent detection10aWoodpeckers1 aVidaña-Vila, Ester1 aNavarro, Joan1 aAlsina-Pagès, Rosa, Ma1 aRamírez, Álvaro uhttps://linkinghub.elsevier.com/retrieve/pii/S0003682X1930508002184nas a2200181 4500008004100000245009100041210006900132520157400201653002501775653002501800653001301825653002201838653001401860653002401874100002501898700002401923856005501947 2020 eng d00aSong-type switching rate in the chaffinch carries a message during simulated intrusion0 aSongtype switching rate in the chaffinch carries a message durin3 a

Birds communicate their motivation and willingness to escalate a territorial conflict with a variety of agonistic signals. One of these, song-type switching, has been suggested to be a conventional signal in male–male interactions. However, this behavior does not show a consistent pattern across species. In this study, we asked whether variation in song-switching rate carries a message for song receivers among territorial chaffinches, Fringilla coelebs. Chaffinch song is well described, but only a few studies have focused on the communicative function of song-type switching or bout duration. Using data from playback experiments, we show here that variation in song-type switching rate affects the response of chaffinches. In response to the low switching rate treatment, territorial males began to sing later, produced fewer songs and more rain calls, decreased flight intensity, and spent more time close to the speaker than during playback of songs with a high switching rate. Our results provide strong evidence that the song-type switching rate is an agonistic signal in the chaffinch and that territorial males exhibit a stronger response toward rivals that sing with a lower song-type switching rate. A secondary purpose of our study was to determine the receivers’ response with respect to their own song rate and song repertoire. We found that the reaction of tested males was correlated with their own spontaneous song rate. This implies that a male’s response to stimuli may be predicted on the basis of his own song output.

10aAggressive signaling10aanimal communication10abirdsong10aFringilla coelebs10asong rate10aSong-type switching1 aDeoniziak, Krzysztof1 aOsiejuk, Tomasz, S. uhttp://link.springer.com/10.1007/s00265-020-2825-201990nas a2200193 4500008004100000245006400041210006200105520138800167653001301555653001901568653001401587653002401601653001101625100002301636700002501659700002201684700002401706856006601730 2020 eng d00aSound sequences in birdsong: how much do birds really care?0 aSound sequences in birdsong how much do birds really care3 a

The complex and melodic nature of many birds' songs has raised interest in potential parallels between avian vocal sequences and human speech. The similarities between birdsong and speech in production and learning are well established, but surprisingly little is known about how birds perceive song sequences. One popular laboratory songbird, the zebra finch (Taeniopygia guttata), has recently attracted attention as an avian model for human speech, in part because the male learns to produce the individual elements in its song motif in a fixed sequence. But psychoacoustic evidence shows that adult zebra finches are relatively insensitive to the sequential features of song syllables. Instead, zebra finches and other birds seem to be exquisitely sensitive to the acoustic details of individual syllables to a degree that is beyond human hearing capacity. Based on these findings, we present a finite-state model of zebra finch perception of song syllable sequences and discuss the rich informational capacity of their vocal system. Furthermore, we highlight the abilities of budgerigars (Melopsittacus undulatus), a parrot species, to hear sequential features better than zebra finches and suggest that neurophysiological investigations comparing these species could prove fruitful for uncovering neural mechanisms for auditory sequence perception in human speech.

10abirdsong10afine structure10aphonology10asequence perception10asyntax1 aFishbein, Adam, R.1 aIdsardi, William, J.1 aBall, Gregory, F.1 aDooling, Robert, J. uhttps://royalsocietypublishing.org/doi/10.1098/rstb.2019.004402516nas a2200217 4500008004100000245010300041210006900144260001600213490000700229520180700236653002502043653002402068653001302092653001402105653002202119653001802141653001702159100002502176700002402201856007302225 2019 eng d00aHabitat-related differences in song structure and complexity in a songbird with a large repertoire0 aHabitatrelated differences in song structure and complexity in a cJan-12-20190 v193 a

Background

Urbanisation has been shown to influence many aspects of animal vocal communication. Much attention has been paid to anthropogenic noise, which is often described as one of the most challenging disturbances for urban dwellers. While a large body of literature describes associations between vocal behavior of avian populations and background noise level, most of these studies were conducted on species with relatively simple songs and small repertoire sizes. This study focuses on the song thrush, Turdus philomelos, a common Eurasian songbird with a complex singing style and large syllable repertoire. Our objective was to determine whether frequency, repertoire and temporal organisation of song parameters vary between birds inhabiting urban and adjacent forest habitats in which ambient noise levels differ.

Results

Songs of urban males were found to be more complex than in conspecifics from natural forest populations. Urban dwellers possessed greater syllable repertoires and repeated syllable sequences more often. In addition, they used a smaller proportion of whistles and a higher proportion of twitter syllables when singing compared to the nonurban males. Moreover, we found significant differences in the minimum and peak frequency of the whistle syllable between studied populations.

Conclusions

These findings may be an example of adaptation of acoustic communication in noisy urban environments, but we also discuss other possible explanations. We emphasize the need for further investigation into the relationships between birdsong and habitat characteristics, male quality, population density and ambient noise level in populations occupying urban and nonurban habitats.

10aanimal communication10aanthropogenic noise10abirdsong10asongbirds10aTurdus philomelos10aUrban ecology10aurbanisation1 aDeoniziak, Krzysztof1 aOsiejuk, Tomasz, S. uhttps://bmcecol.biomedcentral.com/articles/10.1186/s12898-019-0255-702270nas a2200241 4500008004100000022001400041245008000055210006900135260001600204520148200220653002401702653001301726653002301739653002101762653001701783653002201800100002101822700002701843700002901870700002201899700002101921856008601942 2019 eng d a1045-224900aEvidence for differing trajectories of songs in urban and rural populations0 aEvidence for differing trajectories of songs in urban and rural  cJul-08-20203 a

Learned traits, such as foraging strategies and communication signals, can change over time via cultural evolution. Using historical recordings, we investigate the cultural evolution of birdsong over nearly a 50-year period. Specifically, we examine the parts of white-crowned sparrow (Zonotrichia leucophrys nuttalli) songs used for mate attraction and territorial defense. We compared historical (early 1970s) recordings with contemporary (mid-2010s) recordings from populations within and near San Francisco, CA and assessed the vocal performance of these songs. Because birds exposed to anthropogenic noise tend to sing at higher minimum frequencies with narrower frequency bandwidths, potentially reducing one measure of song performance, we hypothesized that other song features, such as syllable complexity, might be exaggerated, as an alternative means to display performance capabilities. We found that vocal performance increased between historical and contemporary songs, with a larger effect size for urban songs, and that syllable complexity, measured as the number of frequency modulations per syllable, was historically low for urban males but increased significantly in urban songs. We interpret these results as evidence for males increasing song complexity and trilled performance over time in urban habitats, despite performance constraints from urban noise, and suggest a new line of inquiry into how environments alter vocal performance over time.

10aanthropogenic noise10abirdsong10aCultural evolution10asexual selection10aUrbanization10avocal performance1 aMoseley, Dana, L1 aPhillips, Jennifer, N.1 aDerryberry, Elizabeth, P1 aLuther, David, A.1 aCandolin, Ulrika uhttps://academic.oup.com/beheco/advance-article/doi/10.1093/beheco/arz142/555110702126nas a2200241 4500008004100000022001300041245005900054210005800113260001600171300001200187490000800199520128200207653001301489653001901502653001401521653002101535653002501556653001901581653001101600100001801611700002201629856023301651 2019 eng d a0003347200aContext-dependent variation of house finch song syntax0 aContextdependent variation of house finch song syntax cJan-01-2019 a33 - 420 v1473 a

We explored the role of social context in the syntactical variation of house finch, Haemorhous mexicanus, songs using both traditional song measures and network analysis. In comparison to solo bouts, the bouts of countersinging males had increased syntax diversity, with higher numbers of simple paths and transition types (but not syllable types) in comparison to solo song, which had high sequence consistency. Both the proportion of introductory syllables and the degree (number of transitions to and from those syllables) increased in countersinging bouts and were an important source of syntactic variability. In contrast, courtship bouts included longer songs and longer syllables than both solo and countersinging bouts, but were similar to solo songs in sequence consistency. The longest courtship songs often included concatenated sequences that formed ‘compound songs’, or repeating strings of main song syllables, which slightly increased the degree of those syllables. Our results suggest that interactions between males are associated with increased syntactic variability in song delivery while female choice favours signals that maintain species-typical syntax and demonstrate fitness in terms of a male's capacity to sing extended songs.

10abirdsong10acountersinging10acourtship10anetwork analysis10asequence consistency10asocial context10asyntax1 aCiaburri, Ivy1 aWilliams, Heather uhttps://linkinghub.elsevier.com/retrieve/pii/S0003347218303373https://api.elsevier.com/content/article/PII:S0003347218303373?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0003347218303373?httpAccept=text/plain02725nas a2200217 4500008004100000022001400041245016200055210006900217260001600286520199500302653001302297653001802310653001202328653002502340653001402365100001802379700002302397700001602420700001602436856005502452 2018 eng d a2193-719200aSinging of Claudia’s Leaf-warbler (Phylloscopus claudiae) in aggressive contexts: role of song rate, song type diversity and song type transitional pattern0 aSinging of Claudia s Leafwarbler Phylloscopus claudiae in aggres cAug-12-20183 a

In many songbirds, males vary certain aspects of their singing behavior when engaged in territorial interactions. Song rate, song type switching rate, song matching, song overlapping, and the usage of specific song types were proposed to be aggressive signals. It is well known that transitions between different song types in a song sequence are non-random in many species, but the signaling significance of non-random vocal streams is poorly understood. We asked whether singing plays a role in male–male interactions in Claudia’s Leaf-warbler. Along with more traditional metrics (i.e., song length, song rate, song type switching rate and song type diversity), we used (1) song sequence linearity (SLIN) and consistency (SCONS) indexes, and (2) applied an information theory approach by means of a first-order relative entropy (RE1) calculation to analyze the role of song type transitional patterns in male–male interactions. The study was conducted in April–June 2016 in Hupingshan National Nature Reserve, Hunan province, China. We simulated territorial intrusion by broadcasting Claudia’s Leaf-warbler songs in territories. Experiments involved 14 different males. A comparison of spontaneous singing with that elicited by playback showed that song rate and song type diversity increased, and that entropy decreased. By contrast, SLIN and SCONS, though significantly correlated with RE1, did not differ between spontaneous singing and singing in response to playback. The decrease of entropy means that the transitions between different song types in a song sequence were determined more by specific factors and predictable and thus more non-random. However, these results were weak, as the decrease of RE1 did not coincide with the expected increase of SLIN, SCONS and S. Our results are thus partly consistent with the idea that non-random vocal structures, along with other song parameters, could play a role in male–male competition.

10abirdsong10acommunication10aEntropy10aPlayback experiments10aTerritory1 aOpaev, Alexey1 aKolesnikova, Yulia1 aLiu, Meishi1 aKang, Zujie uhttp://link.springer.com/10.1007/s10336-018-1614-402119nas a2200181 4500008004100000245013600041210006900177260001600246520146800262653002401730653001301754653002801767653001401795653002001809100003301829700003201862856004301894 2018 eng d00aVocal divergence between two disjunct populations of Giant Antshrike (Batara cinerea) is related to environmental conditions0 aVocal divergence between two disjunct populations of Giant Antsh cApr-11-20193 a

Variation in the avian vocal signals emitted may have a significant impact on species evolution. Vocal divergence in suboscine species like Giant Antshrike (Batara cinerea) may be associated with selective adaptation, since learning has little influence on vocal development and variation in acoustic structure cannot be attributed to learning deviation. Consequently, tracheophone suboscine species are ideal subjects to explore vocal variation, since cultural evolution does not seem to influence vocal variation in this group. Environmental conditions may determine the selection of vocal features because acoustic transmission could be attenuated under certain conditions of temperature, humidity and vegetation cover. Here, we examined vocalizations of Giant Antshrike and assessed possible acoustic variations between two disjunct groups (Andean and Atlantic), correlating the differences to the environmental structure. Univariate and multivariate analysis show temporal and spectral differences between both groups. Andean individuals produce vocalizations with longer duration, faster trill rates, shorter syllable duration and higher frequencies. Environmental features are different between the two populations, and they are correlated to the acoustic structure of vocalizations. Temporal variations arise directly from climatic influence, while spectral divergence could be a secondary effect of morphological adaptation to habitat structure.

10aacoustic adaptation10abirdsong10aenvironmental selection10asuboscine10avocal variation1 aSementili-Cardoso, Guilherme1 aDonatelli, Reginaldo, José uhttp://doi.wiley.com/10.1111/aec.1268200538nas a2200181 4500008004100000022001300041245005700054210005000111260001600161300001400177490000800191653001300199653001600212653002100228653002000249100002100269856006600290 2017 eng d a0003347200aBirdsong ‘performance’ studies: a sad commentary0 aBirdsong performance studies a sad commentary cJan-11-2017 a209 - 2100 v13310abirdsong10aperformance10asexual selection10avocal deviation1 aKroodsma, Donald uhttp://linkinghub.elsevier.com/retrieve/pii/S0003347217303068