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Résumé :
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Capsule The capture-recapture model M(o) is an efficient way to estimate local population size. Aims To test if a single capture-recapture modelling approach, combined with a simple survey method, can produce estimates of local population size from a dataset involving large-scale multi-observer surveys Methods We sampled the presence of Nightjars in three separate sessions at three forests. Territory numbers were estimated using conventional territory-mapping criteria. We ran different capture-recapture models to analyse the detection histories of territories obtained across the three sampling sessions and in the three different forests, using either only registrations of churring birds or all contacts. Results The capture-recapture model M(o), assuming a constant detection probability, was the most efficient one to produce estimates of local population size. Using only two of the three sampling sessions gave less precise, though quite similar, estimates of the number of territories, with standard deviations representing 5-10% of the estimate values. However, this was reduced to 0.7-3.5%, i.e. three to seven times lower, when using the three sessions. Conclusion Repeated sampling sessions to map territories can be efficiently used within the capture-recapture model M(o) to estimate detection probability and produce precise estimates of local population size.
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