Post-Typhoon Mawar population counts of the endangered yǻyaguak (Mariana swiftlet) on Guam

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dc.coverage.spatialMarianas Islands
dc.coverage.temporalApril to November 2023
dc.creatorEben H. Paxton
dc.creatorP. Marcos Gorresen
dc.creatorPaul Cryan
dc.creatorMegan Parker
dc.date.accessioned2024-05-15T16:39:14Z
dc.date.available2024-05-15T16:39:14Z
dc.date.issued2024-05-15
dc.description.abstractThe yǻyaguak (Mariana swiftlet, Aerodramus bartschi) is an endangered cave-roosting species native to Guam and southern Mariana Islands, Micronesia. The population on Guam has declined substantially over the last half century, likely due to the introduction of the brown treesnake (Boiga irregularis), but other factors have been proposed including habitat loss, pesticides, reduced food resources, and powerful storms. On May 24–25, 2023, Guam was hit by the category-4 Typhoon Mawar, which brought wide-spread destruction to the island. Approximately 6 weeks prior to the typhoon in April 2023, we conducted surveys of the three known colonies of yǻyaguak at Mahlac, Maemong, and Fachi caves. This survey provided a baseline population estimate prior to Typhoon Mawar’s landfall. In July 2023, we resurveyed the caves to estimate colony size and assess whether the cave colonies experienced significant declines in the immediate aftermath of the storm. In November 2023, we conducted our regularly scheduled biannual surveys which provided a longer-term assessment of potential impacts from the typhoon. Our counts indicated that in the immediate aftermath (~6 weeks) there was a 7–8% reduction in size of colonies compared to the April 2023 counts, but in November there were larger, 19–35% reductions in the cave colonies from pre-Mawar surveys. These results suggest that the long-term effects of the storm were more detrimental to the yǻyaguak populations than the immediate impacts if these colony size reductions are a result of the storm. Continued monitoring of the yǻyaguak cave colonies will allow for documenting the pace of recovery from the storm.
dc.formatTechnical Report
dc.format.extent11 pages
dc.identifier.citationPaxton, E. H., P. M. Gorresen, P. Cryan, and M. Parker. 2024. Post-Typhoon Mawar population counts of the endangered yǻyaguak (Mariana swiftlet) on Guam. Hawai‘i Cooperative Studies Unit Technical Report HCSU-110. University of Hawai‘i at Hilo. 11 pages.
dc.identifier.urihttps://hdl.handle.net/10790/5392
dc.languageeng
dc.languageother
dc.publisherUniversity of Hawai'i at Hilo
dc.rightshttp://rightsstatements.org/vocab/NoC-NC/1.0/
dc.subjectAerodramus bartschi
dc.subjectbrown treesnake
dc.subjectconservation
dc.subjectGuam
dc.subjectMariana swiftlet
dc.subjectTyphoon Mawar
dc.subjectyǻyaguak
dc.titlePost-Typhoon Mawar population counts of the endangered yǻyaguak (Mariana swiftlet) on Guam
dcterms.rightsCreative Commons
dcterms.typeText
prism.endingpage8
prism.number110
prism.publicationnameHawai'i Cooperative Studies Unit Technical Report Series
prism.startingpagei

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