Nectar and pollen of the invasive century plant Agave americana as a food resource for endemic birds

Abstract

Capsule Flowers of an invasive plant species are more visited by native birds than flowers of ornithophilous endemic plants.Aims To describe the bird guild and its behaviour visiting the century plant Agave americana in an insular environment and to determine which factors are affecting visitation rates.Methods We noted number and species of birds visiting inflorescences on Tenerife, Canary Islands. We used multimodel inference of generalized linear models to analyse the factors affecting the number of visits and the visitor species richness.Results Eighty-one per cent of inflorescences were visited by eight native bird species. All species fed on nectar and only the Atlantic Canary fed also on pollen. Foraging behaviour varied among species. Visitation rate increased with density and diversity of birds and flower characteristics and decreased through the day. The number of species visiting the inflorescences increased with diversity and density of birds in the surroundings and decreased through the day.Conclusion The native bird community uses the invasive century plant as a feeding resource at a higher rate than it uses endemic ornithophilous plants. This could have negative effects for the pollination of endemic plants, but positive effects for birds.