Viability of an endangered population of ortolan buntings: The effect of a skewed operational sex ratio

Steifetten, Øyvind; Dale, Svein

doi:10.1016/j.biocon.2006.03.016

Cited by 78 publications

(112 citation statements)

References 45 publications

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“…Here, we found a negative trend in the relationship between inter-annual population change and the SR. In contrast, a positive trend between population change and the proportion of males breeding was found in ortolan buntings (Emberiza hortulana) with a male-biased sex ratio (Steifetten and Dale, 2006). This result suggests that an adult population of Przewalski's gazelles with a higher proportion of females breeding can substantially increase the population's realized reproductive output (also see Brook et al, 2000a).…”

Section: Sensitivity Analysismentioning

confidence: 99%

Metapopulation viability of a globally endangered gazelle on the Northeast Qinghai–Tibetan Plateau

Jiang

Mallon

2013

Biological Conservation

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Section: Sensitivity Analysismentioning

confidence: 99%

Metapopulation viability of a globally endangered gazelle on the Northeast Qinghai–Tibetan Plateau

Jiang

Mallon

2013

Biological Conservation

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“…Vzrok za to je večja pognezditvena disperzija samic (Dale 2001). Ta faktor dodatno zmanjša možnost preživetja izoliranih populacij vrtnega strnada (Steifetten & Dale 2006). Tudi naša raziskava je pokazala visok delež samcev v populaciji, ki je primerljiv s podatki izolirane norveške populacije vrtnega strnada (Steifetten & Dale 2006).…”

Section: Diskusijaunclassified

“…Ta faktor dodatno zmanjša možnost preživetja izoliranih populacij vrtnega strnada (Steifetten & Dale 2006). Tudi naša raziskava je pokazala visok delež samcev v populaciji, ki je primerljiv s podatki izolirane norveške populacije vrtnega strnada (Steifetten & Dale 2006). Raziskava je tudi pokazala, da so samci vrtnega strnada na Krasu tvorili agregacijo, večjo skupino pojočih samcev.…”

Section: Diskusijaunclassified

Breeding range, population size and population trend of the Ortolan Bunting Emberiza hortulana in Slovenia between 1979 and 2016

Stanič¹,

Kmecl²,

Figelj³

et al. 2017

Acrocephalus

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In this work we investigated the historical and present breeding range of the Ortolan Bunting in Slovenia and studied one of its last remaining breeding grounds in the country. Its range has suffered a marked decline in the last few decades, bringing the species on the brink of extinction in Slovenia. Firstly, we gathered all the available data and field records regarding the species in Slovenia and created several distribution maps outlining the status of the Ortolan Bunting in Slovenia. Thus we were able to confirm the drastic reduction in the species range, now confined to only two larger breeding grounds on the Karst (Kras). Field work was then concentrated on studying and monitoring one of the two last known populations of Ortolan Buntings in Slovenia. We paid special attention to the study of the males’ singing territories. Our main discovery was the presence of a lek in the central part of the study area, where several different male Ortolan Buntings shared their song-posts. In 2013 we counted a total of 18 Ortolan Buntings and found 5 nests, whereas in 2014 we counted 16 individuals, with 4 pairs probably breeding there. The number of breeding pairs is thus significantly lower than the total number of males holding territory. In the period from 2005 to 2016, the population of Ortolan Bunting in Slovenia was in steep decline.

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“…The species has declined steadily the last 50 years in Western Europe, and is currently listed in Norway as critically endangered on the Norwegian red-list. The population size is now only about 100 singing males and declines an average of 8% annually ͑Dale, 2001; Steifetten and Dale, 2006͒. The initial decline of the Norwegian population was probably due to the habitat loss related to changes in agriculture practices ͑Dale, 2001͒.…”

Section: A Species Under Studymentioning

confidence: 99%

“…The initial decline of the Norwegian population was probably due to the habitat loss related to changes in agriculture practices ͑Dale, 2001͒. However, 10 years of intensive study revealed that the main reason for the continuous decrease is female-biased dispersal pattern, which in isolated and patchy population seriously affects sex ratio, behavior of males, and breeding success measured at the population level Steifetten and Dale, 2006͒. It is hoped that increasing our understanding of male ortolan bunting vocalizations will enable us to better understand breeding behavior and reduce the risk of extinction.…”

Section: A Species Under Studymentioning

confidence: 99%

Acoustic model adaptation for ortolan bunting (Emberiza hortulana L.) song-type classification

Jin

Johnson

Osiejuk

2008

The Journal of the Acoustical Society of America

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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 adaptation data to build individual-specific models. Since, as in human speech, individual vocal variability is a significant source of variation in bioacoustic data, acoustic model adaptation is naturally suited to classification in this domain as well. To demonstrate and evaluate the effectiveness of this approach, this paper presents the application of maximum likelihood linear regression adaptation to ortolan bunting ͑Emberiza hortulana L.͒ song-type classification. Classification accuracies for the adapted system are computed as a function of the amount of adaptation data and compared to caller-independent and caller-dependent systems. The experimental results indicate that given the same amount of data, supervised adaptation significantly outperforms both caller-independent and caller-dependent systems.

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Viability of an endangered population of ortolan buntings: The effect of a skewed operational sex ratio

Cited by 78 publications

References 45 publications

Metapopulation viability of a globally endangered gazelle on the Northeast Qinghai–Tibetan Plateau

Metapopulation viability of a globally endangered gazelle on the Northeast Qinghai–Tibetan Plateau

Breeding range, population size and population trend of the Ortolan Bunting Emberiza hortulana in Slovenia between 1979 and 2016

Acoustic model adaptation for ortolan bunting (Emberiza hortulana L.) song-type classification

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