The wild diet of reintroduced Red-and-green Macaws (Ara chloropterus) in the Iberá Wetlands, Argentina

VOLPE, NOELIA L.; ADRIAN S. DI GIACOMO; BERKUNSKY, IGOR

Vancouver

Congreso; 27th International Ornithological Congress, Vancouver, Canada; 2018

International Ornithological Union

Background: The Red-and-green Macaw (Ara chloropterus) reintroduction project aims to restore this species to the savanna of the Iberá Wetlands, northeast Argentina, from where it became extinct in the 19th century. Since October 2015, 17 macaws have been released into the wild inside the Iberá National Park. All individuals were captive-sourced. Ten individuals underwent a pre-release rehabilitation process of 6-12 months, which involved the exposure to an array of 54 different wild fruits. Of these, 35 of the offered species were considered ?accepted? (consumed more than 25% of the occasions).Aims: We analyzed the exploitation of wild food sources of the reintroduced macaws. Methods: Seven macaws were fitted with VHF radio-collars, and followed daily to monitor their movements and consumption of wild fruits. We recorded the location and identity of each individual tree or vine the macaws fed from. Results: Between June 2017 and March 2018 the macaws were observed feeding from 361 different trees and vines, comprising 26 plant species (13 families). Eighty five percent (22) of the consumed plant species had been presented to the macaws during the pre-release stage. Two species were highly consumed: the guava Psidium guajava (56% of the used trees) and the palm Syagrus romanzoffiana (15% of the trees). Four new species were incorporated into the diet after release. These included the pine (Pinus sp.), which comprised 8% of the trees used for feeding. Macaws were also seen eating flowers, which had not been offered to them during the pre-release stage. The used trees were distributed in 43 forest patches, within a radius of 11 km from the release site (mean distance: 3.6 km; range: 0.025 -11.3 km). Conclusions: Reintroduced macaws showed good exploration skills, being able to find fruiting trees at long distances from the release site. The ability of the reintroduced macaws to locate and use wild food sources, despite coming from captive conditions, confirms the flexibility of the species and its capacity to adapt to a new environment. Most of the consumed plant species were offered to the macaws during the pre-release stage. Yet, it is not clear if this early exposure to the fruits contributed to their acceptance in the wild. Controlled experiments should be carried on in order to evaluate the effectiveness of this practice.