Skip to main content
SpringerLink
Log in

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

  • Original Article
  • Published:
European Journal of Wildlife Research Aims and scope Submit manuscript

Abstract

Management decision-making processes require reliable tools providing information on the distribution, abundance, and trend of populations. Wolves vocalize in response to human imitations of howls. Traditionally, this phenomenon has been the basis of a widespread monitoring tool to assess the reproductive status in a wolf pack, as well as to estimate the minimum number of individuals in the pack: the elicited-vocalization technique. However, despite its broad use, only a few attempts to quantify its accuracy have been made so far. Here, we carried out a test to evaluate the accuracy of estimates obtained from the elicited-vocalization technique. We administered “chorus tests” to 205 human subjects, 182 rangers—with different level of experience with wolves—and 23 subjects with no previous experience with the species. We found that the estimates of the number of wolves participating in a chorus were not accurate, regardless of the experience of the listener (the correct number of wolves was only determined in 32% of tests). Listeners, however, identified pups vocalizing 98% of the times when there were pups in the chorus. They also reported the presence of pups when they were not present with a high frequency (71%). Estimating the number of individuals by the unaided human ear is flawed because of the bias inherent in the elicited-vocalization technique. Howling surveys have a low degree of selectivity to confirm the presence of pups. Thus, we make recommendations to improve the elicited-vocalization technique as a tool to monitor the presence of pups.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5

Similar content being viewed by others

References

  • Apollonio M, Mattioli L, Scandura M et al (2004) Wolves in the Casentinesi Forests: insights for wolf conservation in Italy from a protected area with a rich wild prey community. Biol Conserv 120:249–260

    Article  Google Scholar 

  • Baker MC (2004) The chorus song of cooperatively breeding laughing kookaburras (Coraciiformes, Halcyonidae: Dacelo novaeguineae): characterization and comparison among groups. Ethology 110:21–35

    Article  Google Scholar 

  • Bates DM, Sarkar D (2007) The lme4 library. [Online], Available: http://lib.stat.cmu.edu/R/CRAN/

  • Bibby CJ, Burgess ND, Hill DA (1992) Bird census techniques. Harcourt Brace & Company, London

    Google Scholar 

  • Boitani L, Fuller TK (2000) Research techniques in animal ecology. Controversies and consequences. Columbia University Press, New York

    Google Scholar 

  • Bradbury JW, Vehrencamp SL (2011) Principles of animal communication, 2nd edn. Sinnauer Associates Publishers, Sutherland

    Google Scholar 

  • Burnham KP, Anderson DR (2002) Model selection and multimodel inference: a practical information theoretic approach. Springer-Verlag, New York

    Google Scholar 

  • Chapron G, Kaczensky P, Linnell JDC et al (2014) Recovery of large carnivores in Europe’s modern human-dominated landscapes. Science 346(6216):1517–1519

    Article  CAS  PubMed  Google Scholar 

  • Dekker D (1985) Response of wolves, Canis lupus, to simulated howling on a homesite during fall and winter in Jasper National Park, Alberta. Can field-naturalist 99:90–93

    Google Scholar 

  • Dugnol B, Fernández C, Galiano G, Fernández C (2007) Wolf population counting by spectrogram image processing. Appl Math Comput 186:820–830

    Google Scholar 

  • Filibeck U, Nicoli M, Rossi P, Boscagli G (1982) Detection by frequency analyzer of individual wolves howling in a chorus: a preliminary report. Boll di Zool 49:151–154

    Article  Google Scholar 

  • Gaines WL, Neale GK, Naney RH (1995) Response of coyotes and gray wolves to simulated howling in North-Central Washington. Northwest Sci 69:217–222

    Google Scholar 

  • Galaverni M, Palumbo D, Fabbri E et al (2012) Monitoring wolves (Canis lupus) by non-invasive genetics and camera trapping: a small-scale pilot study. Eur J Wildl Res 58:47–58

    Article  Google Scholar 

  • Gazzola A, Avanzinelli E, Mauri L et al (2002) Temporal changes of howling in south European wolf packs. Ital J Zool 69:157–161

    Article  Google Scholar 

  • Gregory RD, Gibbons DW, Donald PF (2004) Bird census and survey techniques. In: Sutherland WJ, Newton I, Green RE (eds) Bird ecology and conservation; a handbook of techniques. Oxford University Press, Oxford, pp 17–56

    Chapter  Google Scholar 

  • Hallberg KI (2007) Information in a long-distance vocal signal: chorus howling in the coyote (Canis latrans). The Ohio State University, Columbus

    Google Scholar 

  • Harrington FH (1989) Chorus howling by wolves: acoustic structure, pack size and the beau geste effect. Bioacoustics-The Int J Anim Sound its Rec 2:117–136

    Google Scholar 

  • Harrington FH, Asa CS (2003) Wolf communication. In: Mech LD, Boitani L (eds) Wolves: behavior, ecology, and conservation. University of Chicago Press, Chicago, pp 66–103

    Google Scholar 

  • Harrington FH, Mech LD (1978) Howling at two Minnesota wolf pack summer homesites. Can J Zool 56:2024–2028

    Article  Google Scholar 

  • Harrington FH, Mech LD (1982) An analysis of howling response parameters useful for wolf pack censusing. J Wildl Manag 46:686–693

    Article  Google Scholar 

  • Hopp SL, Morton ES (1998) Sound playback studies. In: Hopp SL, Owren MJ, Evans CS (eds) Animal acoustic communication: sound analysis and research methods. Springer-Verlag, Berlin Heidelberg, pp 323–352

    Chapter  Google Scholar 

  • Jiménez J, García EJ, Llaneza L et al (2016) Multimethod, multistate Bayesian hierarchical modeling approach for use in regional monitoring of wolves. Conserv Biol:1–23

  • Joslin PWB (1967) Movements and home sites of timber wolves in Algonquin Park. Am Zool 7:279–288

    Article  Google Scholar 

  • Kaczensky P, Chapron G, von Arx M et al (2013) Status, management and distribution of large carnivores—bear, lynx, wolf & wolverine—in Europe. Istituto di Ecologia Applicata, Rome

    Google Scholar 

  • Kershenbaum A, Root-Gutteridge H, Habib B et al (2016) Disentangling canid howls across multiple species and subspecies: structure in a complex communication channel. Behav Process 124:149–157

    Article  Google Scholar 

  • Koenig R (2008) Rangers assess toll of Congo conflict on threatened mountain gorillas. Science 322(5909):1778

    Article  CAS  PubMed  Google Scholar 

  • Kuijper DPJ, de Kleine C, Churski M et al (2013) Landscape of fear in Europe: wolves affect spatial patterns of ungulate browsing in Białowieża Primeval Forest, Poland. Ecography (Cop) 36:1263–1275

    Article  Google Scholar 

  • Lehner PN (1978) Coyote vocalizations: a lexicon and comparisons with other canids. Anim Behav 26:712–722

    Article  Google Scholar 

  • Llaneza L, Ordiz A, Palacios V, Uzal A (2005) Monitoring wolf populations using howling points combined with sign survey transects. Wildl Biol Pract 1:108–117

    Article  Google Scholar 

  • Llaneza L, García EJ, López-Bao JV (2014) Intensity of territorial marking predicts wolf reproduction: implications for wolf monitoring. PLoS One 9:e93015

    Article  PubMed  PubMed Central  Google Scholar 

  • Mitchell MS, Ausband DE, Sime CA et al (2008) Estimation of successful breeding pairs for wolves in the Northern Rocky Mountains, USA. J Wildl Manag 72:881–891

    Article  Google Scholar 

  • Nakagawa S, Schielzeth H (2013) A general and simple method for obtaining R2 from generalized linear mixed-effects models. Methods Ecol Evol 4:133–142

    Article  Google Scholar 

  • Nowak S, Jedrzejewski W, Schmidt K et al (2007) Howling activity of free-ranging wolves (Canis lupus) in the Białowieza Primeval Forest and the Western Beskidy Mountains. J Ethol 25:231–237

    Article  Google Scholar 

  • Nowak S, Myslajek RW, Jedrzejewska B et al (2008) Density and demography of wolf, Canis lupus population in the western-most part of the polish Carpathian Mountains, 1996-2003. Folia Zool 57:392–402

    Google Scholar 

  • Palacios V, Font E, Márquez R (2007) Iberian wolf howls: acoustic structure, individual variation, and a comparison with North American populations. J Mammal 88:606–613

    Article  Google Scholar 

  • Palacios V, López-Bao JV, Llaneza L et al (2016) Decoding group vocalizations: the acoustic energy distribution of chorus howls is useful to determine wolf reproduction. PLoS One 11:e0153858

    Article  PubMed  PubMed Central  Google Scholar 

  • Passilongo D, Mattioli L, Bassi E et al (2015) Visualizing sound: counting wolves by using a spectral view of the chorus howling. Front Zool 12:22

    Article  PubMed  PubMed Central  Google Scholar 

  • Peters G, Wozencraft WC (1989) Acoustic communication by fissiped carnivores. In: Gittleman J (ed) Carnivore behavior, ecology, and evolution. New York University Press, Ithaca, pp 14–49

    Chapter  Google Scholar 

  • R Development Core Team (2010) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria

  • Schassburger RM (1993) Vocal communication in the timber wolf, Canis lupus, Linnaeus: structure, motivation, and ontogeny. Advances in Ethology Series 30

  • Sinclair ARE, Fryxell JM, Caughley G (2009) Wildlife ecology, conservation and management, second. Wiley, Oxford

    Google Scholar 

  • Sinnott JM, Brown CH (1993) Effects of varying signal duration on pure-tone frequency discrimination in humans and monkeys. J Acoust Soc Am 93:1541–1546

    Article  CAS  PubMed  Google Scholar 

  • Sutherland WJ (2006) Ecological census techniques. A handbook, 2nd edn. Cambridge University Press, Cambridge

    Book  Google Scholar 

  • Valeix M, Loveridge AJ, Chamaillé-Jammes S et al (2009) Behavioral adjustments of African herbivores to predation risk by lions: spatiotemporal variations influence habitat use. Ecology 90:23–30

    Article  CAS  PubMed  Google Scholar 

Download references

Acknowledgements

We are in debt to the rangers of the Regional Government of Galicia and Picos de Europa National Park in Spain, as well as the rangers of the different counties with wolf presence in Sweden. We thank all volunteers collaborating in this study and conducting the “chorus test.” With respect to the chorus howls recordings used in this research, we thank Junta de Castilla y León, Principado de Asturias, and Xunta de Galicia for allowing us to record wild wolves and F. Petrucci-Fonseca and S. Pinho (CRLI), J. Escudero (La Dehesa), P. España and E. Sánchez (Cañada Real), and P. Abad (Carpín) for allowing us to obtain recordings from the captive wolves under their care. JVLB was supported by a Juan de la Cierva research contract (JCI-2012-13066) from the Spanish Ministry of Economy and Competitiveness. This is scientific paper no. 17 of the Iberian Wolf Research Team (IWRT).

Author information

Authors and Affiliations

  1. Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Universidad de Valencia, Valencia, Spain

    Vicente Palacios & Enrique Font

  2. A.RE.NA. Asesores en Recursos Naturales, S.L. Perpetuo Socorro n°12-Entresuelo, 2B, 27003, Lugo, Spain

    Vicente Palacios, Emilio José García & Luis Llaneza

  3. Grimsö Wildlife Research Station, Department of Ecology, Swedish University of Agricultural Sciences, Riddarhyttan, Sweden

    Linn Svensson, Jens Frank & José Vicente López-Bao

  4. Research Unit of Biodiversity (UO/CSIC/PA), Oviedo University, Mieres, Spain

    José Vicente López-Bao

Authors
  1. Vicente Palacios
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Enrique Font
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Emilio José García
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Linn Svensson
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Luis Llaneza
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Jens Frank
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. José Vicente López-Bao
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Vicente Palacios.

Ethics declarations

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Palacios, V., Font, E., García, E.J. et al. Reliability of human estimates of the presence of pups and the number of wolves vocalizing in chorus howls: implications for decision-making processes. Eur J Wildl Res 63, 59 (2017). https://doi.org/10.1007/s10344-017-1115-4

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1007/s10344-017-1115-4

Keywords

Search

Navigation