02826nas a2200265   4500008004100000022001300041245010000054210006900154260001600223520198800239653002502227653002502252653002502277653000802302653002102310653003002331653002102361653001702382653001702399653003402416110003002450700001802480700001802498856004402516       2018                        eng d  a0110646500aUsing paired acoustic sampling to enhance population monitoring of New Zealand’s forest birds0 aUsing paired acoustic sampling to enhance population monitoring   cNov-11-20193 a<p>Large-scale bird monitoring can provide valuable insights about drivers of population change across different spatial and temporal scales. Yet, challenging terrain and survey costs hinder the collection of data needed to estimate absolute abundance or population densities for New Zealand&rsquo;s forest birds. Acoustic sampling is being used more frequently to increase efficiency in avian monitoring and paired sampling facilitates robust density estimation from acoustic data. In paired sampling, point counts are conducted simultaneously by human observers and autonomous recording units (ARUs) to allow estimation of statistical offsets that correct biases in ARU data relative to human observers. These offsets can then be used to calibrate count data collected only by ARUs in a larger sampling scheme. However, the effectiveness of paired sampling has not yet been evaluated in New Zealand. We assessed bias in bird counts from ARUs relative to traditional point counts and evaluated whether paired sampling reduced ARU bias, when present, at 280 count stations in six indigenous forest patches on the North Island from January to April 2017. For 13 forest bird species, we estimated &delta;, a statistical offset that represents the ratio of the effective detection radius (EDR) of the ARU data to human count data and compared bias in density estimates from ARUs relative to human observers between models with and without &delta; offsets. We found that &delta; estimates of EDR ratios were near 1.0 and 95% confidence intervals around &delta; overlapped 1.0 for nine of 13 species. Furthermore, densities produced by ARU counts were unbiased relative to human point counts for nine of 13 species. When models included &delta; offsets, ARU density estimate bias was removed for all species. Thus, paired acoustic sampling offers a promising strategy for increasing the efficiency, and spatial and temporal coverage of bird population monitoring across New Zealand.</p>
10a5-minute bird counts10aabundance estimation10aacoustic survey bias10aARU10aaudio monitoring10aautonomous recording unit10aavian monitoring10abioacoustics10apoint counts10apopulation density estimation1 aColorado State University1 aBombaci, Sara1 aPejchar, Liba  uhttps://newzealandecology.org/nzje/3356