Trevor Bak
Ayesha Genz
Richard J. Camp
2022
<p><span>The U.S. Navy, through Micronesian Environmental Services, surveyed landbirds in the Military </span><span>Lease Area on Tinian Island in May and June 2021 using point-transect distance sampling </span><span>methods. There were 2,074 individuals of 14 species detected during 123 point counts. Six </span><span>species were detected during >50% of the counts and were observed at relatively high </span><span>abundances, while eight species occurred at <50% of the counts and were uncommon to rare. </span><span>Densities of native landbirds in the Military Lease Area ranged from the uncommon Mariana </span><span>kingfisher (<i>Todiramphus albicilla</i>) at 0.46 birds/ha (95% confidence interval [CI] = 0.33–0.63) </span><span>to the very abundant bridled white-eye (<i>Zosterops conspicillatus</i>) at 102.63 birds/ha (95%CI = </span><span>86.70–122.91). Most distances recorded during the 2021 Military Lease Area survey were </span><span>rounded to distance intervals of 0 and 5. Measuring exact distances of detected animals is </span><span>preferable to collecting distances grouped into bins or rounding. Direct comparison with </span><span>previously published estimates was not possible because of changes in the sampling frame; </span><span>however, densities of six species were greater, two were smaller, and one was similar to the </span><span>2008 survey estimates for the Hagoi, Diablo, and Masalog regions. Our findings indicate that </span><span>the landbird community in the Military Lease Area appears to be dynamic and resilient.</span></p>
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Hawai`i Cooperative Studies Unit, University of Hawai`i at Hilo
2021 Tinian Island forest bird abundance estimates
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