The selection of native and invasive plants by frugivorous birds in Maine

Frugivores and fruit-producing plants often have a mutualistic relationship in which plants provide animals with nutritious fleshy pulp in return for the dispersal of seeds within the fruit. Although the selection and dispersal of invasive plant species by birds has major implications for native animals, plants, and communities, few studies have focused on whether birds select invasive versus native fruits. I compared fruit removal and fruit choice by birds, and fruit energy content of two invasive plant species, Lonicera tatarica and Rosa multiflora, and two native plant species, Cornus amomum and Viburnum opulus, in central Maine. Frugivores preferentially consumed fruit from L. tatarica and C. amomum, and they did not discriminate between R. multiflora and V. opulus during choice trials. Although the two native plant species had significantly higher caloric content than the two invasive species, higher energy density of native plants was not directly correlated with more rapid fruit removal or fruit preference.