Floreana Mockingbird

The Floreana Mockingbird (Nesomimus trifasciatus) is highly vulnerable to changes in its environment and the presence of humans, and has a restricted breeding range. Scientists from the Charles Darwin Foundation (CDF) are acting now to prevent the loss of this characteristic species from Galapagos.

Contents 1 Unique to Galapagos 2 Vulnerability 3 CDRS research activities

Unique to Galapagos

The Charles or Floreana Mockingbird is one of four mockingbird species endemic to Galapagos. This species is extinct on Floreana Island, but continues to survive on Floreana's two satellite islets, Champion and Gardner-by-Floreana. Its range does not overlap with any other mockingbird species.

The Floreana Mockingbird has dark brown- grayish upperparts, dull white underparts and a brown band across the chest. The eyes are redbrown.

The Floreana Mockingbird feeds mainly on Opuntia cacti. They also prefer nesting in Opuntia.

Vulnerability

The Floreana mockingbird is listed as Endangered on the IUCN Red List.

In 2006, the population of this species was 79 birds. Small populations that are restricted in range are particularly vulnerable. Severe weather events, such as El Niño cycles and drought, cause dramatic changes in the size of the population. Global warming may increase the occurrence and severity of El Niño cycles. IUCN recommends that the species should be changed to Critically Endangered if extreme fluctuations continue.

The extinction of Floreana Mockingbirds on the main island is likely to be due to a combination of factors. In addition to climate effects, it has been associated with the loss of Opuntia cacti, which were affected by invasive herbivores and are now very rare on this island.

Predatory cats and black rats that eat mockingbird eggs are likely to have played a role in the loss of Floreana mockingbirds from the main island.

The smooth-billed ani is an introduced bird that preys on nestlings. The parasitic Philornis fly has previously been found in nests on the islets.

As with other mockingbird species, the Floreana Mockingbird is likely to be susceptible to introduced avian diseases, such as avian pox. To date, avian pox has not affected the Floreana islets. Wet years may see the arrival of introduced birds to the islets, bringing with them the devastating effects of avian disease.

CDRS research activities

If suitable steps are not taken to protect the Floreana Mockingbird immediately, this could be the first extinct bird species in Galapagos.

The last islet refuges of the Floreana Mockingbird are under the strict protection of Galapagos National Park Service (GNPS); access for tourists and scientists is restricted to prevent the arrival of introduced species. Scientists at the CDF monitor annually the numbers and health of these populations. They use this information to make recommendations to the GNPS on how best to protect this species. Invasive species are identified and controlled to keep the Floreana islets in a pristine condition. The presence of smooth-billed anis must be controlled to prevent them preying on nestlings.

The arrival of fire ants (Solenopsis geminata and Wasmannia auropunctata) would be disastrous for the Floreana Mockingbird. The CDF and the GNPS have successfully eradicated fire ants on some islands, but this relies on early discovery. Monitoring for fire ants has been added to the annual survey.

In other studies, the CDF and the GNPS are working with visiting scientists to understand the genetics, feeding patterns, and the reproductive biology of the Floreana Mockingbird. It may be necessary to attempt to counteract the effects of drought on the survival of this species, by providing means to collect water during dry periods.

To ensure the survival the species, a comprehensive plan for its recovery is crucial. Although the islets near Floreana are important refuges for this species, these are too small to maintain a large population. Its survival will depend on its reintroduction to the main island.

Before this can happen, the GNPS needs to control the invasive species threatening the island. Goats, donkeys, and pigs have been successfully eradicated from other islands such as Santiago and northern Isabela. These as well as rats and cats must be controlled on Floreana. Once eliminated, the restoration of the forests of giant Opuntia can begin, allowing the repatriation of the Floreana mockingbird to its original home.