From the cage to the wild: introductions of Psittaciformes to Puerto Rico.

Wilfredo Falcón,Raymond L Tremblay

doi:10.7717/peerj.5669

Wilfredo Falcón, Raymond L Tremblay

Open Access

https://doi.org/10.7717/peerj.5669

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Abstract

Introduced psittacine birds can become highly invasive. In this study, we assessed invasions of Psittaciformes in Puerto Rico. We reviewed the literature, public databases, citizen science records, and performed in situ population surveys across the island to determine the historical and current status and distribution of psittacine species. We used count data from Ebird to determine population trends. For species whose populations were increasing, we modelled their potential distribution using niche modeling techniques. We found 46 Psittaciformes in Puerto Rico, of which 26% are only present as pets, at least 29 species have been reported in the wild, and of those, there is evidence that at least 12 species are breeding. Our results indicate that most introduced species which have been detected as established still persist, although mostly in localized areas and small populations. Clear evidence of invasiveness was found for Brotogeris versicolurus and Myiopsitta monachus, which have greatly expanded their range in recent years. Psittacara erythrogenys and Eupsittacula canicularis also showed population increases, although to a lesser degree. The niche models predicted suitable areas for the four species, and also indicate the potential for range expansion. We discuss the factors leading to invasion success, assess the potential impacts, and we discuss possible management strategies and research prospects.

Highlights

With the globalization of economies, the rate of species introductions has risen considerably to the extent that the shifts in species distributions and the reorganization of biodiversity are considered a signature of the Anthropocene (Seebens et al, 2017)
At least 46 psittacine species are present on the island
Of the 46 species of Psittaciformes found in Puerto Rico, at least 63% have been reported in the wild elsewhere, and 26% are considered as established or invasive

Summary

Introduction

With the globalization of economies, the rate of species introductions has risen considerably to the extent that the shifts in species distributions and the reorganization of biodiversity are considered a signature of the Anthropocene (Seebens et al, 2017). Psittaciformes are among the exotics species most commonly sold as pets, with twothirds of the known species in this group known to occur in the pet trade (parrots, conures and cockatoos) (Cassey et al, 2004b). In the 1990’s the global pet trade in Psittaciformes generated USD $1.4 billion and was largely supplied by four million wild-caught birds (Thomsen et al, 1992). Four general modes of introductions to native habitats have been identified for parrots: releases by traders due to oversupply or legal complications (Forshaw, 1973; Robinson, 2001), or the accidental or intentional releases by pet owners (Blackburn, Lockwood & Cassey, 2009)

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