Reliability of human estimates of the presence of pups and the number of wolves vocalizing in chorus howls: implications for decision-making processes

Palacios, Vicente; Font, Enrique; García, Emilio José; Svensson, Linn; Llaneza, Luís; Frank, J. Howard; López‐Bao, José Vicente

doi:10.1007/s10344-017-1115-4

Cited by 14 publications

(5 citation statements)

References 29 publications

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“…Canids were usually targeted as one of the most interesting cases of chorusing animals because their monitoring is one of the central issues in conservation biology [ 41 , 42 ]. The study of Passilongo and colleagues [ 43 ] showed that a spectral examination of the chorus howling allowed to estimate real versus bioacoustically predicted chorus size in a way far more precise and objective that field estimations by ear.…”

Section: Introductionmentioning

confidence: 99%

Call and be counted! Can we reliably estimate the number of callers in the indri's (Indri indri) song?

et al. 2018

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Estimating the number of animals participating in a choral display may contribute reliable information on animal population estimates, particularly when environmental or behavioral factors restrict the possibility of visual surveys. Difficulties in providing a reliable estimate of the number of singers in a chorus are many (e.g., background noise masking, overlap). In this work, we contributed data on the vocal chorusing of the indri lemurs (Indri indri), which emit howling cries, known as songs, uttered by two to five individuals. We examined whether we could estimate the number of emitters in a chorus by screening the fundamental frequency in the spectrograms and the total duration of the songs, and the reliability of those methods when compared to the real chorus size. The spectrographic investigation appears to provide reliable information on the number of animals participating in the chorusing only when this number is limited to two or three singers. We also found that the Acoustic Complexity Index positively correlated with the real chorus size, showing that an automated analysis of the chorus may provide information about the number of singers. We can state that song duration shows a correlation with the number of emitters but also shows a remarkable variation that remains unexplained. The accuracy of the estimates can reflect the high variability in chorus size, which could be affected by group composition, season and context. In future research, a greater focus on analyzing frequency change occurring during these collective vocal displays should improve our ability to detect individuals and allow a finer tuning of the acoustic methods that may serve for monitoring chorusing mammals.

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Section: Introductionmentioning

confidence: 99%

Call and be counted! Can we reliably estimate the number of callers in the indri's (Indri indri) song?

et al. 2018

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“…It is known that wolves respond to the howl of their conspecifics or the wailer on the hunt. They can also respond to other sources of sound, such as a horn (Palacios et al 2017, Domken et al 2021. This can be explained by the similar acoustic structure of all these sounds, namely, they are long and harmonic with a close frequency range.…”

Section: Discussionmentioning

confidence: 98%

Vocal interaction between Eurasian Eagle-Owl (Bubo bubo) and canines (Carnivora, Canidae)

Andreychev

2023

Ornis Hungarica

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We recorded vocal interaction in the natural environment of an Eurasian Eagle-Owl (Bubo bubo) with canines Gray Wolves (Canis lupus), Red Foxes (Vulpes vulpes) and domestic dogs (Canis familiaris). Vocalization was recorded using Olympus digital voice recorders. The calls of the male Eurasian Eagle-Owl were recorded by us in the frequency range of 200–420 Hz. The howl of a Gray Wolf was recorded in the frequency range from 300 to 1,100 Hz. Red Fox barking was recorded in the frequency range from 750 to 1,000 Hz. Barking of domestic dogs was recorded in the frequency range from 250 to 1,500 Hz. The vocalization of the Eurasian Eagle-Owl had an independent character inherent in the biology of the species. The Eurasian Eagle-Owl, with its cries, involuntarily provoked the entry of canines into joint vocal interaction, which can be explained by the high social activity of the latter. Co-vocalizations of the Eurasian Eagle-Owl and canines were noted in winter, spring and autumn, but mainly in spring (50%). The increased use of autonomous voice recorders, which record spontaneous vocalizations emitted by animals over long periods, will allow us to better document and study the importance of such interspecific interactions.

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“…Wydeven. Such howling surveys are somewhat accurate for the detection of pups in experimental, field tests but are not accurate for counting pack size or pup numbers in those same tests [ 66 ]. Although we cannot extrapolate to the whole state or assume that response to human howls would continue as in the past, their anecdotal data suggest a scenario with a lower estimate is also plausible.…”

Section: Methodsmentioning

confidence: 99%

Uncertainty and precaution in hunting wolves twice in a year

Treves

Louchouarn

2022

PLoS ONE

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When humanity confronts the risk of extinction of species, many people invoke precautions, especially in the face of uncertainty. Although precautionary approaches are value judgments, the optimal design and effect of precautions or lack thereof are scientific questions. We investigated Wisconsin gray wolves Canis lupus facing a second wolf-hunt in November 2021 and use three legal thresholds as the societal value judgments about precautions: (1) the 1999 population goal, 350 wolves, (2) the threshold for statutory listing under the state threatened and endangered species act, 250 wolves; and (3) state extirpation <2 wolves. This allows us to explore the quantitative relationship between precaution and uncertainty. Working from estimates of the size wolf population in April 2021 and reproduction to November, we constructed a simple linear model with uninformative priors for the period April 2021-April 2022 including an uncertain wolf-hunt in November 2021. Our first result is that the state government under-counted wolf deaths in the year preceding both wolf-hunts. We recommend better scientific analysis be used when setting wolf-hunt quotas. We find official recommendations for a quota for the November 2021 wolf-hunt risk undesirable outcomes. Even a quota of zero has a 13% chance of crossing threshold 1. Therefore, a zero death toll would be precautionary. Proponents for high quotas bear the burden of proof that their estimates are accurate, precise, and reproducible. We discuss why our approach is transferable to non-wolves. We show how scientists have the tools and concepts for quantifying and explaining the probabilities of crossing thresholds set by laws or other social norms. We recommend that scientists grapple with data gaps by explaining what the uncertainty means for policy and the public including the consequences of being wrong.

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Reliability of human estimates of the presence of pups and the number of wolves vocalizing in chorus howls: implications for decision-making processes

Cited by 14 publications

References 29 publications

Call and be counted! Can we reliably estimate the number of callers in the indri's (Indri indri) song?

Call and be counted! Can we reliably estimate the number of callers in the indri's (Indri indri) song?

Vocal interaction between Eurasian Eagle-Owl (Bubo bubo) and canines (Carnivora, Canidae)

Uncertainty and precaution in hunting wolves twice in a year

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