A new audio-visual technique for effectively monitoring nest predation and the
behaviour of nesting birds
Diane Colombelli-Négrel A , Jeremy Robertson A , B and Sonia Kleindorfer A
A School of Biological Sciences, Flinders University, GPO Box 2100, Adelaide,
SA 5001, Australia.
B Corresponding author. Email:
Abstract
Effective monitoring techniques are vital to understanding a range of
behaviours and their consequences for evolution of life histories. Video and
photographic monitoring is regularly used but rarely with audio monitoring even
though it can identify birds or predators off-camera, and detect alarm calls
and songs. We developed a 4-channel audio-visual recording system to
continuously monitor the nests of Superb Fairy-wrens (Malurus cyaneus). This
innovative system worked autonomously for 3 days and identified repeat visits
by some predators, detected nest predation by Grey Currawong (Strepera
versicolor) and two rodents, and provided new insights into nest defence,
provisioning rates, vocalisations of parents and nestlings and interactions
between them.
Emu 109(1) 83-88
Submitted: 16 September 2008 Accepted: 17 December 2008 Published: 10
March 2009
Full text DOI: 10.1071/MU08048
© Royal Australasian Ornithologists Union 2009
Pitfalls in using counts of roaring stags to index red deer (Cervus elaphus)
population size
Paolo Ciucci A , B , Gianluca Catullo A and Luigi Boitani A
A Dipartimento di Biologia Animale e dell'Uomo, Università 'La Sapienza' di
Roma, Viale dell'Università 32 - 00185, Roma, Italy.
B Corresponding author. Email:
Abstract
Counting roaring stags during the rut has been proposed as a means to assess
deer population size and trends but few, if any, attempts have been made to
evaluate the reliability of this technique. By means of a commonly used field
protocol, we assessed to what extent relative abundance estimates of red deer
(Cervus elaphus) based on roaring-stag counts in the northern Apennines (Italy)
were susceptible to exogenous and unpredictable sources of variability. By
using up to 26 simultaneous observers in an area of 5218 ha, we estimated
densities from 0.45 to 0.61 roaring stags per 100 ha in 3 consecutive years
(1992-94), corresponding to annual changes in the number of counted roaring
stags ranging from -21% to +35.7%. However, only in two of the three years were
seasonal trends and peaks in roaring activity apparent, and timing of the
survey was not always synchronous with the roaring peak. In addition, annual
and nocturnal variation in roaring activity, and weather conditions during the
survey, might have influenced the counts to some extent, probably determining
high Type I and Type II error rates. We contend that additional sources of
error, associated with unknown demographic and ecological settings, may further
increase unreliability of the technique when it is used to estimate absolute
density of red deer populations. We conclude by emphasising that managers
should not use this method for population monitoring unless they can prove it
can yield reliable results.
Wildlife Research 36(2) 126-133
Submitted: 27 August 2007 Accepted: 6 November 2008 Published: 20
February 2009
Full text DOI: 10.1071/WR07121
© CSIRO 2009
DISCLAIMER:
This Email message is for the sole use of the intended recipient and may
contain confidential and privileged information. Any unauthorised review, use,
disclosure or distribution is prohibited. If you are not the intended
recipient, please contact the sender by reply Email and destroy all copies as
well as the original message. All views expressed in this Email are those of
the sender, except where specifically stated otherwise, and do not necessarily
reflect the views of Forests NSW.
|