- a Czech University of Life Sciences Prague, Faculty of Environmental Sciences, Department of Ecology, Kamýcká 129, Praha 6 - Suchdol 165 21, Czech Republic
- b Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Department of Animal Science and Ethology, Kamýcká 129, Praha 6 - Suchdol 165 21, Czech Republic
- c Institute of Animal Science, Department of Ethology, Přátelství 815, Praha 10 - Uhříněves 104 00, Czech Republic
- Received 29 October 2014, Revised 9 February 2015, Accepted 13 March 2015, Available online 20 March 2015
Highlights
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- The method applied did not deliver satisfactory estimates of surviving owl fledglings.
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- It can be assumed the method will not work reliably also in other smaller owl species.
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- The probability of hearing a fledgling decreased with distance from the natal nestbox.
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- The probability of hearing a fledgling decreased as the time of night progressed.
Abstract
Counting
of calling males during territorial or nuptial displays is a method
widely used for census of populations of wild vertebrates during the
pre-breeding and breeding periods, particularly in relation to census of
populations of wild birds. In principle, a similar method could be used
for assessing numbers of surviving offspring, by monitoring of begging
calls, but is used only rarely. We explored the possibility of assessing
post-fledging survival of Tengmalm's Owl young by counting the number
of individuals begging for food. This method did not however deliver
satisfactory estimates of numbers of surviving fledglings and its
accuracy depended on time of night, distance from the natal nestbox, and
presence or absence of begging calls. We suggest that this method can
be used in Tengmalm's Owls for rough estimates only and our finding
could be applicable also for other, generally smaller, owl species whose
fledglings exhibit quick dispersion from the nest site after the
fledging.
Keywords
- Begging calling;
- Boreal Owl;
- Method reliability;
- Mortality rate;
- Untrained observer;
- Radiotelemetry
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