Two butterflies native to South Florida are most likely extinct, according to the U.S. Fish and Wildlife Service.

The butterflies, the Zestos (Epargyreus zestos oberon) and rockland grass (Hesperia meskei pinocayo) skippers, are likely extinct. These butterflies were historically found only in South Florida.

The Zestos skipper was last observed at the Key West Tropical Forest and Botanical Garden on Stock Island on January 24, 2004. This butterfly had not been observed on mainland Florida in many decades. The rockland grass skipper was last observed at Everglades National Park in 2000, with an additional population occurring on Big Pine Key until 1999.

In recent years, butterfly scientists and activists have surveyed extensively in order to determine the status of the Zestos and rockland grass skippers, and other imperiled butterflies. Surveys have been conducted at numerous locations, including many public conservation lands, throughout southern Florida and the Florida Keys.

The Zestos skipper occurs commonly throughout the Bahamas and eastern Antilles. Based on this information, the Zestos skipper was not considered imperiled, globally, and therefore the butterfly was never considered for listing as endangered in the United States. Unfortunately, it was only recently discovered that the Zestos skipper in Florida was in fact a distinct subspecies, found nowhere else. Before the conservation agencies could move to protect it, it was gone. Similarly, the rockland grass skipper was thought to be extinct in 1980s. However, it was briefly rediscovered on Big Pine Key in 1999, but disappeared again before recovery actions could be implemented.

There are a number of factors influencing butterfly populations in southern Florida, the largest being loss, modification and fragmentation, and in some instances inconsistent management, of the natural habitats that butterflies and their larval hostplants depend on. Other possible factors include: small population size, poaching, use of pesticides for mosquito control, and predation from nonnative species, such as fire ants, and the influence of climate change.

In an attempt to galvanize butterfly conservation efforts in southern Florida, the Florida Fish and Wildlife Conservation Commission (FWC), the U.S. Fish and Wildlife Service, the National Park Service, the North American Butterfly Association, as well as a number of other agencies and organizations formed the Imperiled Butterflies of Florida Working Group. The group meets quarterly to address butterfly-related issues in south Florida.

In addition, IBWG maintains a SharePoint to the latest information on butterfly conservation activities throughout southern Florida. The SharePoint can be visited here.

“We greatly appreciate the efforts of the IBWG,” said Larry Williams, the Service’s Florida state supervisor for Ecological Services. “We’re saddened by the loss of the Zestos and rockland grass skippers and hope their loss serves as a wake-up call that we really need to intensify our efforts to save other imperiled butterflies in South Florida.”

Recent efforts of the IBWG include monitoring and conservation of the federally endangered Schaus swallowtail and Miami blue butterflies in the Florida Keys. Since 2011, IBWG members have monitored Schaus swallowtail populations and initiated major restoration efforts within Biscayne National Park in order to increase availability of the butterfly’s habitat and larval hostplants. These efforts may also include implementation of captive rearing and reintroduction actions, if needed, to help recover the swallowtail.

A recent state wildlife grant by the FWC to the Florida Natural Areas Inventory involved members of the North American Butterfly Association as citizen scientists to survey and monitor the populations levels of other imperiled south Florida butterfly species. Plans are being made to continue these monitoring efforts after the grant period ends in hopes of being able to take proactive steps for protecting these other south Florida butterfly species before the need to consider federally listing them.

“The FWC will continue facilitating the IBWG’s collaborative efforts, while promoting awareness for butterfly conservation, the habitats that sustain them, and the roles they play as an indicator species in the larger environment,” FWC wildlife biologist Mary Truglio said.

In addition, the Service has funded continuing surveys and research of Miami blue populations within Key West National Wildlife Refuge. In the near future, the Service, along with IBWG members will develop a recovery plan for the Miami blue.