Eleutherodactylus coqui
coqui

Coqui & greenhouse frogs:
alien Caribbean frogs in Hawaii

Problematic frogs trouble people, environment
Eleutherodactylus planirostris
greenhouse frog

coqui (L) and greenhouse frog (R) with dime and pencil
coqui (L) and greenhouse frog (R)
Non-native Caribbean frogs* have become established in some areas in Hawaii (*coqui and greenhouse frogs: Eleutherodactylus spp. [not true 'tree frogs', as some have called them]). They cause both environmental problems and problems for people. These creatures have a special appeal to some people; however, these frogs are not native to Hawaii, and their existence in Hawaii poses a great threat to native species in Hawaii . Although the call of the coqui is often beloved by residents of the coqui's native habitat, the extremely loud noise they make in Hawaii (presumably louder than in native habitats because of higher concentrations of populations) has been reported to be extremely annoying to numerous Hawaii residents and visitors. (For example, a recent article in a health-related magazine cites coqui as causing sleepless nights on the island of Oahu.)


The frogs

Eleutherodactylus coqui
coqui
Eleutherodactylus coqui: Up to 52mm (2") in length; brown or gray-brown with variable patterns including light mid-dorsal stripe, dorsal chevrons, dark suprascapular W's, or unicolor. Call a two-note, high-pitched "co-qui" (ko-kee').
Eleutherodactylus planirostris
greenhouse frog
Eleutherodactylus planirostris: Up to 36mm (1.5") in length; mottled dark brown and tan, or brown with a mid-dorsal tan stripe. The call  of this species is a diffuse series of irregularly pitched chirps or twitters.


Where do they live?


Species


Known Location in Hawaii


Native Range


Native Habitat


Eleutherodactylus coqui
Maui, Big Island (60,000 acres)*, Oahu; nurseries and surrounding forest, residential areas, hotels Puerto Rico mesic and rain forest

0-1000m (3900') elev.

Eleutherodactylus planirostris Big Island, Oahu; nurseries and adjacent ohia scrub, residential areas Cuba, Bahamas, Caymans dry and mesic forest;

0-610m (2000') elev.

*2009, Raymond McGuire (DLNR/DOFAW), pers. comm.


Detailed information

Ecological attributes

Only the ecology of Eleutherodactylus coqui has been well-studied. This species can occur in its native rain forest at densities exceeding 20,000 animals/ha (8100/acre) and consume an average of 114,000 prey items/night/ha (46,000 prey/night/acre). Densities in one nursery on Big Island probably equal or exceed this. They prey primarily on arthropods, but will also forage on snails and small frogs.

Eleutherodactylus planirostris consumes similar, though smaller, prey items to Eleutherodactylus coqui and can occur at high densities, but probably requires warmer temperatures for survival than does Eleutherodactylus coqui. Hence, it is unlikely to invade mid-elevation rain forest. All three species are nocturnally active, feeding, calling, and mating at this time. Eleutherodactylus coqui forages from the ground to up in the canopy. Eleutherodactylus coqui calls primarily from 1-2m (3-7') elevation on exposed perches. It hides in forest leaf litter during the day and shuttle to elevated perches at night. Preferred daytime retreats are large rolled leaves, although animals will use artificial hide boxes constructed of bamboo sections if made available. Eleutherodactylus planirostris is terrestrial and climbs only a few centimeters above ground level. For all species, eggs are laid in protected sites among the leaf litter, are guarded by the male parent, and require approximately 2-3 weeks to develop directly into small froglets. There is no tadpole stage and, consequently, no need for access to surface water. Generation time for Eleutherodactylus coqui is approximately eight months, and Eleutherodactylus planirostris is probably similar.


Anthropocentric concerns ("People problems")

Eleutherodactylus coqui has a loud, piercing call[online sounds!] that often disturbs people's sleep (calls are typically measured at 90-100 decibels at a distance of 0.5m [1.5'] from the frog). This same problem has been noted for other species of Eleutherodactylus introduced to areas outside their native ranges. Several populations of frogs have come to our attention as complaints from disturbed residents, visitors, or hotel managers. All of these have been for small choruses of frogs. Large choruses can be deafening but are restricted so far to a couple of nurseries and a few residential areas.

Frog calls online
We have several recordings of Eleutherodactylus coqui calls online.
single frog calling:
short (41 kb)
longer (102 kb)
or a chorus:
short (60 kb)
longer (163 kb)
coqui chorus at Lava Tree State Park (Big Island)
03 October 2000 (MPG format):
short (93 kb)
longer (176 kb)


Conservation concerns

Eleutherodactylus coqui poses the greatest threat to native Hawaiian ecosystems because it can invade mid-elevation moist and rain forests. It can be expected to exert tremendous predation pressure on a variety of native arthropods and, possibly, snails. Consequently, they will likely have an indirect negative effect on the remaining native forest birds, most of which are partially or largely insectivorous. The frogs may serve as an energy sink in native ecosystems into which they insert themselves due to lack of native predators, although it is more likely they will instead serve as an additional food source enhancing population levels of rats and mongoose, thereby increasing predation pressure on native forest birds.


For more information...

For more information about these frogs, see the:

If you need more information about these frogs, have specific questions about them (or other alien animal pests in Hawaii), contact the  Hawaiian Ecosystems at Risk project (HEAR) via e-mail:  webmaster@hear.org.


To report locations of these frogs...

To report locations of these frogs, , use the appropriate contact information for your island provided by CTAHR. contact the Hawaii Department of Agriculture via phone or fax.


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The Hawaiian Ecosystems at Risk (HEAR) project is currently funded by the Pacific Basin Information Node (PBIN) of the National Biological Information Infrastructure (NBII) through PIERC (USGS) with support from HCSU (UH-Hilo). More details are available online. Pacific Basin Information Node (PBIN) National Biological Information Infrastructure (NBII)

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Unless otherwise noted, technical details in the main text of this page were last updated on 08 February 2000 based on information provided by Fred Kraus. Photos on this page are by Allen Allison, Hawaii Biological Survey . This page is a product of the Hawaii Ecosystems at Risk Project . This page was created on 08 March 1999 by PT , and was last updated on 28 January 2009 by  PT.