Elucidating dietary secrets of the Blue-headed Macaw, Primolius couloni (Sclater, 1876), through citizen-sourced photographs

Abstract

Dietary data are vital for understanding species' resource requirements and ecological roles and supporting conservation efforts. The Blue-headed Macaw, Primolius couloni, is a vulnerable and endemic species in the Amazon. Due to their rarity, elusive nature, complex forest canopy habitat, and occurrence in remote areas, we minimally know their dietary habits. To address this gap, we analysed photographs of Blue-headed Macaws posted on wildlife-focused social media platforms, specifically targeting images that capture foraging behaviour on plants. Photographs depicting the same foraging were included only once, and those where the plants were not identified were discarded. By doing so, we identified 36 distinct foraging events (or photos), primarily taken between July and October, concentrated in specific locations in Peru and Brazil, a potential seasonality in foraging. We documented 27 food plant species and items such as nectar (n = 9 photos), pulp (8), seeds (7), buds, bark (5 each), aril, and leaves (n = 1 photo each). Notably, floral resources, including nectar, are a potentially important food in the driest months. Using Levin's Index (Ba), we identified a broad dietary niche, indicating a generalist feeding strategy with a wide variety of plant species (Ba = 0.69) and food items (Ba = 0.88). Additionally, the study revealed interactions such as florivory, seed predation, bark consumption, and potential mutualistic roles like pollination and seed dispersal. Our photo-centric approach here expanded the known dietary spectrum of the Blue-headed Macaw from four to 31 plant species, offering new insights for conservation strategies. We recommend the preservation of identified food plants and suggest using these data to inform habitat restoration efforts that support the macaws' dietary needs and ecological functions. Future research should focus on continuous monitoring of these food plants to deepen our understanding of seasonal foraging trends and ecological interactions and refine conservation approaches.