| acoustic model adaptation for ortolan bunting (emberiza hortulana l.) song-type classification. | automatic systems for vocalization classification often require fairly large amounts of data on which to train models. however, animal vocalization data collection and transcription is a difficult and time-consuming task, so that it is expensive to create large data sets. one natural solution to this problem is the use of acoustic adaptation methods. such methods, common in human speech recognition systems, create initial models trained on speaker independent data, then use small amounts of adap ... | 2008 | 18345846 |
| perceptually motivated wavelet packet transform for bioacoustic signal enhancement. | a significant and often unavoidable problem in bioacoustic signal processing is the presence of background noise due to an adverse recording environment. this paper proposes a new bioacoustic signal enhancement technique which can be used on a wide range of species. the technique is based on a perceptually scaled wavelet packet decomposition using a species-specific greenwood scale function. spectral estimation techniques, similar to those used for human speech enhancement, are used for estimati ... | 2008 | 18646979 |
| acoustic censusing using automatic vocalization classification and identity recognition. | this paper presents an advanced method to acoustically assess animal abundance. the framework combines supervised classification (song-type and individual identity recognition), unsupervised classification (individual identity clustering), and the mark-recapture model of abundance estimation. the underlying algorithm is based on clustering using hidden markov models (hmms) and gaussian mixture models (gmms) similar to methods used in the speech recognition community for tasks such as speaker ide ... | 2010 | 20136210 |
| sing softly to evoke a response only from a recent intruder. | low-amplitude soft songs have been described in many birds, but in most species, research has addressed only broadcast songs. soft songs may have a similar or distinctive structure in comparison to broadcast songs produced in order to defend a territory and attract females. in some species, such soft songs were found to be produced in an aggressive context and were the best predictors of conflict escalation and later physical attack. however, such observations are not consistent across all speci ... | 2018 | 30366107 |
| song duration mediates responses of territory owner in a songbird species with a small song repertoire. | song is a sexually selected trait that is involved in mate attraction and territory defence in birds. songs may convey information about different male quality components. they are flexible in terms of frequency, amplitude, and duration. although changes in song duration are common, the function of this behaviour has been studied less strongly. it is known that song duration changes within a singing bout and may provide information about aggressive motivation. we tested whether the elongation an ... | 2017 | 28553008 |
| frequency shift in homologue syllables of the ortolan bunting emberiza hortulana. | results of this study indicate that in the ortolan bunting emberiza hortulana, syllables of the same shape on sonograms (i.e. homologue syllables) often significantly differ between males in frequency parameters. typically, homologue syllables of different males in the studied population had a similar bandwidth but shifted minimal and maximal frequencies. we found no strong evidence supporting that the frequency of homologue syllables is affected by the body size variation of males. besides, fre ... | 2005 | 15639387 |
| dispersal of male ortolan buntings away from areas with low female density and a severely male-biased sex ratio. | dispersal is expected to enhance individual fitness, and individuals should thus disperse from areas with poor conditions to areas with more favourable conditions. few studies have compared conditions before and after dispersal of the same individuals, and in birds little is known about the effects of sex ratio and female density on male dispersal decisions. in this study we examined various fitness-related parameters that adult male ortolan buntings, emberiza hortulana, might use as cues in the ... | 2012 | 21800058 |
| unravelling migration connectivity reveals unsustainable hunting of the declining ortolan bunting. | in france, illegal hunting of the endangered ortolan bunting emberiza hortulana has been defended for the sake of tradition and gastronomy. hunters argued that ortolan buntings trapped in southwest france originate from large and stable populations across the whole of europe. yet, the european commission referred france to the court of justice of the european union (eu) in december 2016 for infringements to legislation (ip/16/4213). to better assess the impact of hunting in france, we combined p ... | 2019 | 31131318 |
| stable isotopes reveal captive vs wild origin of illegally captured songbirds in france. | naturally occurring stable isotopes of several elements are important tracers in the study the wildlife ecology including the identification of origins for migration research, investigations of trophic relationships, and in the forensic determination of illegally harvested and captive fauna. extensive illegal trapping for use as decoys and in cuisine has contributed to drastic declines of ortolan bunting emberiza hortulana populations breeding and migrating through france. we contrasted feather ... | 2019 | 31377688 |