Gorresen, P.M., Paxton, E.H., and Cryan, P.M., 2023, Guam, Mariana swiftlet counts, 2019-2023: U.S. Geological Survey data release, https://doi.org/10.5066/P90R04RD.
Summary
The yǻyaguak (Mariana swiftlet; Aerodramus bartschi) is an endangered cave-nesting species historically found on Guam and the southern Mariana Islands, Micronesia. The population on Guam has been severely impacted by the introduction of the brown treesnake (Boiga irregularis). Population status assessments have, however, been challenging due to the limitations of traditional counting methods, which rely on visual observations at cave entrances and are prone to inaccuracies. To improve count accuracy, we estimated yǻyaguak population size and relative nesting activity using thermal and near-infrared videography at Mahlac, Maemong and Fachi Caves from April 2019 to April 2023. This study demonstrates the potential of thermal and near-infrared [...]
Summary
The yǻyaguak (Mariana swiftlet; Aerodramus bartschi) is an endangered cave-nesting species historically found on Guam and the southern Mariana Islands, Micronesia. The population on Guam has been severely impacted by the introduction of the brown treesnake (Boiga irregularis). Population status assessments have, however, been challenging due to the limitations of traditional counting methods, which rely on visual observations at cave entrances and are prone to inaccuracies. To improve count accuracy, we estimated yǻyaguak population size and relative nesting activity using thermal and near-infrared videography at Mahlac, Maemong and Fachi Caves from April 2019 to April 2023. This study demonstrates the potential of thermal and near-infrared videography for improved monitoring of yǻyaguak colonies and nesting activity.
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Related External Resources
Type: Related Primary Publication
Gorresen, P. M., P. Cryan, M. Parker, F. Alig, M. Nafus, and E. H. Paxton. 2024. Videographic monitoring at caves to estimate population size of the endangered yǻyaguak (Mariana swiftlet) on Guam. Endangered Species Research 53:139–149. Available: https://doi.org/10.3354/esr01296
Mariana swiftlet bird and nest counts were obtained during surveys from 2019 to 2023. Here we present details of the bird and nest counts collected for this study. This data release consists of two tabular datasets: (1) Mariana swiftlet colony size and nest counts, Guam, 2019-2023, and (2) Mariana swiftlet nest cluster counts, Guam, 2019-2023.
Preview Image
Nesting Mariana Swiftlets revealed by near-infrared video. Photo: M. Gorresen.