Field observations and citizen science reveal ecological insights into rare and threatened parrots in the Philippines

Despite their charismatic appeal and threatened conservation status, parrots of the genera Tanygnathus and Prioniturus remain poorly studied throughout their range. Their inconspicuous behaviour, elusive nature, and rarity further hinder efforts to gather comprehensive ecological data. In this study, we describe the breeding behaviour, diet, and nesting phenology of the Blue-naped Parrot Tanygnathus lucionensis and the Green Racquet-tail Prioniturus luconensis, combining field observations and citizen science data to acquire insights into their ecology. Field observations were conducted at Subic Watershed Forest Reserve from February to June 2022 and March to August 2023. Results show that T. lucionensis exhibits a long breeding period, with multiple copulation events, male-to-female regurgitative feeding, and biparental care—traits consistent with the reproductive behaviour of Old World parrots. However, fieldwork did not locate any nests of actively breeding P. luconensis during the study period. To supplement field observations, we analyzed 1,281 media records of both parrots dating from 2012 to 2025, sourced from two citizen science platforms: eBird and Facebook. These records revealed that P. luconensis breeds year-round, while T. lucionensis breeds predominantly in the dry season. Both species are confirmed as mixed plant resource feeders, primarily consuming fruits but also feeding on flowers, leaves, and bark. Notably, 73% of records were native plant species from diverse families, asserting the importance of planting native species as food resources for parrots. Our findings provide much-needed baseline information to inform future ecological research and conservation strategies for these understudied parrot species.