A native parrot as an invasive plant controller

Abstract

Generalist psittacines (parrots) can adjust to anthropogenic ecosystems by taking advantage of novel opportunities therein, such as by feeding on introduced plant species (Wilson J Ornithol 2008; doi.org/10.1676/07-038.1). In the city of Ilha Solteira (within the state of São Paulo, Brazil), a native blue-and-yellow macaw (Ara ararauna) – shown here – consumes flower buds of the African tulip tree (Spathodea campanulata) to access the calyx water, which is rich in amino acids. Such behavior, considered a dietary innovation (Ornitol Neotrop 2015; doi.org/10.58843/ornneo.v26i2.27), is a case of florivory of a non-native plant by a native animal. Florivory diminishes plant fitness by decreasing, and even eliminating, the chances that fruits and seeds will form (New Phytol 2021; doi.org/10.1111/nph.17670). According to the IUCN's Global Invasive Species Database, the African tulip tree is ranked 88 out of “100 of the World's Worst Invasive Alien Species” (https://bit.ly/3ZvinOX). Outside of its native range in West Africa, the tree can degrade tropical ecosystems not only by altering habitat structure and ecological processes but also by reducing biodiversity (Anthr Sci 2022; doi.org/10.1007/s44177-021-00004-y). Notably, macaws’ florivory provides some degree of biological control, which could be high given that the birds en masse can consume more than 100 flower buds in a single feeding bout lasting only a few minutes. Indeed, since 2014 (when the macaws discovered this food resource), we have rarely observed nearby African tulip trees bearing fruit and thus seeds, thereby limiting daughter plant recruitment.