CONTENT - International Society of Zoological Sciences

ICZ2008 – Abstracts S15
Spectral energy distribution as a tool for determining the
presence of pups in wolf chorus howls
Vicente Palacios 1 , Luis Llaneza 1 , Benjamin Dugnol 2 , Carlos
Fernández 2 , Gonzalo Galiano 2 and Julián Velasco 2
1
A.RE.NA. Asesores en Recursos Naturales, S. L., C/ Perpetuo
Socorro, 12 - entlo B, 27003, Lugo, Spain
2
Departamento de Matemáticas, Universidad de Oviedo, C/ Calvo
Sotelo, 33007, Oviedo, Spain
Researchers need reliable methods that provide accurate data on
the distribution, abundance, and population trend of a species in
order to advise wildlife managers. The number of packs is often
used as an indicator for determining the status of the wolf, Canis
lupus, over large areas. As a general rule, only the dominant pair
in a pack breeds and pup presence is taken as an evidence of the
existence of a pack. Response to simulated howls is commonly
used by wolf researchers to locate wolf litters during the summer.
Nevertheless, acoustic structure of chorus howls is complex and
discriminating in the field the presence of pups in a chorus is
sometimes a difficult task due to the highly modulated
vocalizations emitted, especially as pups grow up. In this study we
test the potentiality of analysing the spectral energy distribution of
choruses for distinguishing vocalizations emitted by pups from
those emitted by adult wolves. We analyzed wolf chorus howls
recordings with known pack composition. Choruses were divided
into segments of five seconds of duration. For each segment we
measured some variables related to the spectral energy
distribution of the signal and identified the types of vocalizations
present. Our results show that the frequency at which the
maximum energy peak occurs could be an important variable for
developing an easy way to discriminate between adults and pups
vocalizations.
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