Overview

The smooth-billed ani was introduced to Galapagos in the 1960s. It is thought that anis were introduced deliberately by farmers to help manage tick infestations which were killing livestock. They were first introduced on Isabela and then over the next 50 years, spread to all but one of the major islands, Darwin, and have now reached an estimated population of 250,000.

Instead of feeding on ticks, anis feed on a variety of native wildlife, including endemic finch nestlings. They have also been observed robbing the nests of native yellow warblers and mockingbirds.

In addition, anis are effective dispersers of the seeds of the highly damaging invasive hill raspberry. They are also hosts of the invasive fly Philornis downsi, a parasite which causes high chick mortality in many native bird species and is a major threat to the mangrove finch, the bird most at risk of extinction in Galapagos.

Conservation actions

Research is underway to better understand the biology and ecology of smooth-billed anis, which will help determine the most effective measure to control populations. The answers may lie in the eradication project undertaken on Floreana island in October 2023. The Restoring Floreana project, which is partly funded by GCT, aims to reintroduce 12 locally extinct species by eradicating invasive and introduced species including rats that have decimated native species populations. In October 2023, following the removal of non-target species including finches from the island for their protection, the team began the eradication using aerial and manual delivery of poisoned baits. While this eradication did not target any non-native bird species such as anis, there is now interest in looking into the impact of such eradications on smooth-billed ani populations.