Parrots are largely considered plant antagonists as they usually destroy the seeds they feed on. However, there is evidence that parrots may also act as seed dispersers. We evaluated the dual role of parrots as predators and dispersers of the Critically Endangered Parana pine (Araucaria angustifolia). Eight of nine parrot species predated seeds from 48% of 526 Parana pines surveyed. Observations of the commonest parrot indicated that 22.5% of the picked seeds were dispersed by carrying them in their beaks. Another five parrot species dispersed seeds, at an estimated average distance of c. 250 m. Dispersal distances did not differ from those observed in jays, considered the main avian dispersers. Contrary to jays, parrots often dropped partially eaten seeds. Most of these seeds were handled by parrots, and the proportion of partially eaten seeds that germinated was higher than that of undamaged seeds. This may be explained by a predator satiation effect, suggesting that the large seeds of the Parana pine evolved to attract consumers for dispersal. This represents a thus far overlooked key plant-parrot mutualism, in which both components are threatened with extinction. The interaction is becoming locally extinct long before the global extinction of the species involved.

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Amazona is the largest genus of the Psittacidae, one of the most threatened bird families. Here, we study four species of Amazona (Amazona brasiliensis, A. pretrei, A. vinacea, and A. rhodocorytha) that are dependent on a highly vulnerable biome: the Brazilian Atlantic Forest. To examine their distribution and abundance, we compile abundance estimates and counts, and develop site-occupancy models of their geographic range. These models integrate data from formal research and citizen science platforms to estimate probabilistic maps of the species’ occurrence throughout their range. Estimated range areas varied from 15,000 km2 for A. brasiliensis to more than 400,000 km2 for A. vinacea. While A. vinacea is the only species with a statistical estimate of abundance (~8000 individuals), A. pretrei has the longest time series of roost counts, and A. rhodocorytha has the least information about population size. The highest number of individuals counted in one year was for A. pretrei (~20,000), followed by A. brasiliensis (~9000). Continued modeling of research and citizen science data, matched with collaborative designed surveys that count parrots at their non-breeding roosts, are essential for an appropriate assessment of the species’ status, as well as for examining the outcome of conservation actions.

Population size is a key predictor of extinction risk and is critical to listing species in IUCN threat categories. The population size of parrots-one of the most threatened bird families-is often assessed using roost counts, which suffer from multiple sources of uncertainty that need to be addressed in monitoring efforts. To improve estimates of abundance for endangered Vinaceous-breasted Parrot (Amazona vinacea), we compared extensive roost counts over the whole range of the species (Argentina, Paraguay, Brazil) with an intensive regional survey designed to address five sources of uncertainty about parrot abundance in western Santa Catarina state (WSC), Brazil, in 2016 and 2017. We estimated regional-scale abundance using a sampling design that minimizes double counting and an N-mixture model of replicated count data, which accounts for imperfect detection, implemented in a Bayesian framework. The whole-range counts amounted to 3,888 and 4,084 individuals in 2016 and 2017, respectively; regional estimates were 945 ± 50 and 1,393 ± 40 individuals, for the same two years. We found no evidence of population growth because the increase in numbers matched an increase in observation effort on both spatial scales. When extrapolating the WSC abundance estimate to three hypothetical geographical range areas of the species, under the simplifying assumption of homogenous density, we obtained values above the whole-range counts, but within the same order of magnitude, putting the global population size of Vinaceous-breasted Parrot in the thousands of individuals. Although our estimates of abundance and geographic range are larger than those currently reported by the IUCN, we suggest that Vinaceous-breasted Parrot remain in the 'Endangered' IUCN threat category pending further investigation of population trends. We recommend that roost-monitoring programs for parrots consider and address sources of 3 uncertainty through field protocols and statistical analysis, to better inform assessments of population size, trends, and threat status.

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The Endangered Vinaceous-breasted Parrot, Amazona vinacea, is endemic to the Atlantic Forest. Habitat fragmentation and nest poaching have had a substantial impact on the conservation of the species. These anthropogenic factors, combined with uncertainty regarding the species’ ecology, distribution and population size, make it difficult to plan management actions. This study aimed to monitor the population size of the Vinaceous-breasted Parrot in a communal roost in southern Brazil to identify monthly and annual variation. The study also aimed to characterize the vegetation of different sites used to roost. Roost counts were performed at dawn or dusk with two observers located around the roost area. Each observer recorded the number, time and flight direction of parrots arriving or departing the roost. The highest number of individuals recorded in the roost was 184 during the non-breeding period. The months with the highest means were March, January and May, while those with the lowest were October, November and September. The number of individuals in the roost varied throughout the year, possibly due to food availability at the site. The sites frequently used as roosts were characterized by having high anthropogenic influence and the absence of an understory. The creation, maintenance and expansion of protected areas to provide food resources and nesting sites, as well as the maintenance of forest fragments in private properties, are essential for the conservation of this parrot.