A tiny butterfly federally listed as endangered. Down to a few hundred individuals. Devastated by habitat loss, hurricanes, and possibly invasive predators.

Also called: Miami Blue

Native status: Native; federally endangered

§ Quick facts

SizeWingspan 1.9–2.6 cm (0.75–1.0 in)
Weight~0.05 g
LifespanAdults 1–2 weeks; multiple generations per year
OrderLepidoptera
FamilyLycaenidae

§ Encyclopedia

The Miami blue is a small butterfly that is native to coastal areas of southern Florida. It is a subspecies of Thomas's blue. Once common throughout its range, it has become critically endangered, and is considered to be near extinction. Its numbers have recently been increased by a captive breeding program at the Florida Museum of Natural History.

Source: Wikipedia — Miami blue Licensed under CC BY-SA 4.0

§ Identification

Field marks. Tiny blue butterfly: males bright iridescent blue above; females duller blue-gray. Underside white-gray with small black eyespots near tail.

Similar species. Cassius Blue (longer tail). Ceraunus Blue (different spot pattern). Other Lycaenids — expert ID often required.

Voice. N/A

§ Diet & behavior

Diet. Adults: nectar. Larvae: nickerbean (Caesalpinia bonduc) and balloon vine, growing in coastal tropical hammocks.

Behavior. Federally endangered (2012, emergency listing). Once locally common from Tampa to the Keys; reduced to a handful of individuals on remote Florida Keys. Believed extinct after Hurricane Andrew (1992) until small population rediscovered in 1999. Hurricanes, climate change, sea-level rise, and host plant loss all threats. Captive breeding at the Florida Museum of Natural History; reintroductions ongoing.

§ Range

Restricted to Florida Keys

§ Habitat

Coastal hammocks and dune areas

§ Threats

Habitat loss, hurricane impacts, climate change, sea-level rise.

§ Conservation status

According to the IUCN Red List, the miami blue butterfly is currently classified as Critically Endangered.

§ What helps

Support Florida Keys conservation. Don't collect coastal plants. Donate to USFWS recovery.

Support our work More ways to help

§ Further reading

§ Sources cited

  • USFWS Miami Blue Recovery
  • Florida Museum of Natural History
  • Florida Park Service
  • The Nature Conservancy Florida