Restoration of the Floreana Mockingbird

Mockingbirds (Nesominmus sp.) are attractive, curious and easily observed in the Galapagos Islands. When Charles Darwin visited the islands in 1835, he discovered and participated in the description of the four mockingbird species of Galapagos. During his short visit, he was able to observe a great abundance of these clever birds. His experience in the archipelago was critical in the development of his theory of evolution by natural selection.

Today, three of the four species of Galapagos mockingbirds are on the Red List for birds. The mockingbird of Floreana (N. trifasciatus) is considered critically endangered, primarily due to a drastic reduction in population size and distribution. Its survival during the next 100 years is questionable. At the end of the 19th century, the Floreana mockingbird became extinct on its island of origin and is currently restricted to two satellite islets close to the northern coast of Floreana – Champion and Gardner by Floreana.

The Threats

The extinction of the mockingbird on Floreana was directly related to the presence of introduced species, including cats, rats, goats, burros and pigs. The cats and black rats attack birds and their nests. Goats, burros and pigs destroyed the once-abundant Opuntia cactus forests, the preferred habitat of the mockingbird. It is also probable that the presence of domestic birds (primarily chickens) could have transmitted the viruela disease, potentially mortal to the mockingbirds.

The last refuges of the Floreana mockingbird, Champion and Gardner by Floreana, are small, pristine islets, under the protection of the Galapagos National Park Service (GNPS). To ensure that the mockingbird population survives in these refuges, the Charles Darwin Foundation (CDF) completes an annual census to determine the size and health of the population and to highlight any trends, both positive and negative. These annual visits also ensure rapid discovery of new threats, such as the introduction of invasive species or disease.

The current population on Champion (the smaller of the two islets) fluctuates between 20-40 individuals, while Gardner by Floreana maintains a population of 60-80 birds. Annual fluctuations in abundance are dependent upon precipitation. It is clear that with an overall population under 100 individuals, the probability of an ecological disaster is extremely high. If there is not an immediate and concerted effort to effectively manage and protect the Floreana mockingbird, it may become the first bird species to reach extinction in the Galapagos Islands.

Action Plan

Continue the annual census of the Floreana mockingbirds and monitoring of introduced species on Champion and Gardner by Floreana.

Early detection of population declines or the arrival of invasive species is critical to ensure the protection of the Floreana mockingbird in its two natural refuges. Regular monitoring is relatively effective for discovering introduced vertebrates but is not sufficient for identifying other potential threats such as the arrival of aggressive fire ants (Solenopsis geminata and Wasmania auropunctata), species that have been already dispersed to several other islands in the archipelago. Their arrival on Champion or Gardner by Floreana would be disastrous for the Floreana mockingbird. The CDF and the GNPS have been successful at combating fire ants in other islands, but success is dependent upon early detection. Therefore, additional monitoring to detect the arrival of fire ants must be added.

Intensify research on behavior, natural history and ecology of the Floreana mockingbird.

The CDF and the GNPS collaborate with researchers from Switzerland and the United States to increase our understanding of the genetics, feeding behavior and reproductive biology of the Floreana mockingbird. The current research would be enhanced with additional study of the genetic structure of the population, providing critical information for the protection of the species.

Develop a management plan for the recuperation of the Floreana mockingbird.

To ensure the long-term survival of the Floreana mockingbird, a workshop of international experts on the biology and conservation of mockingbirds will be held to evaluate the current available knowledge on the Floreana mockingbird, identify important gaps in knowledge, and develop a comprehensive plan for the recuperation of the species. This portion of the Action Plan has the highest priority.

Re-introduce the Floreana mockingbird to its native island.

Although both Champion and Gardner by Floreana provide an important refuge for this species, they are too small to sustain a large mockingbird population. Ultimately, the survival of the species will depend upon its re-establishment on its island of origin, Floreana. To ensure success, prior to the re-introduction of mockingbirds, the GNPS must expand its successful program of eradication of large introduced mammals to Floreana. Major successes have already been achieved on some of the larger islands – Isabela, Santiago, Pinta and Marchena. Beginning this year, the attention of the eradication team will be focused on Floreana. Once these primary threats have been eliminated from Floreana, restoration of the Opuntia forests will begin and it will be possible to re-establish the mockingbird population on its island of origin.

Please support Galapagos Conservancy and efforts to restore the Floreana mockingbird. Our success depends on our members’ involvement.

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