Distribution, behaviour, and provenance of Oriental Dollarbirds Eurystomus orientalis in Micronesia, including the first two records from the Mariana Islands

Abstract

We document the status of Oriental Dollarbird Eurystomus orientalis in Micronesia, a region extralimital to the generally accepted geographic range of the species. Our review yielded 34 Micronesian records between 1938 and 2019, with 27 at Palau, four at Yap, and one at Pohnpei in the Caroline Islands, as well as one each at Guam and Saipan, which are the first for the Mariana Islands. Expanded observer effort since 2000 has produced an increase in regional sightings, with birds detected in ten of the 18 years from 2002 to 2019. Examination of museum specimens (n = 3) and photographs of wild dollarbirds (n = 10) confirmed all but one individual as belonging to the migratory Australasian subspecies E. o. pacificus. Timing of records, with nearly all between mid April and mid October, largely matches the known migration and overwintering periods for E. o. pacificus, further indicating that most records involved this taxon.