Coqui Frogs Would Love Haiku

Imagine going to bed at night, but instead of peace and quiet, the night is pierced by a deafening cacophony of mating calls coming from a population of frogs not much bigger than a quarter. For the residents of Puna on the Big Island, it’s not a nightmare, it’s reality.



The Coqui frog (Eleutherodactylus coqui) is a native of Puerto Rico and is thought to have arrived in Hawaii via plant shipments. In just a few years, the coqui frog (pronounced “ko-KEE” like the sound the frog makes) has spread widely throughout the Big Island and there have been infestations on other islands as well.


The frog has become a major problem on the Big Island because of its shrill after-dusk mating call which disturbs residents and tourists, and has depressed real estate sales in areas where populations are heavy.


The frogs lay their tiny eggs inside leaves, flowers and loose soil. They are difficult to see and only adult males call at night. Unlike other frog species, Coquis do not need standing water to reproduce; froglets hatch from eggs.

On Oahu, a sizable population of coqui frogs were found at the Iwilei Home Depot store in Honolulu where eggs or juveniles likely arrived in plant shipments from the Big Island.


In Haiku Plantations, we have a large population of what are called “greenhouse frogs” (Eleutherodactylus planirostris). These frogs look quite similar to the Coqui frog, but their mating calls are completely different. Coqui frogs have a 90-100 decibel call --- as loud as a large vacuum cleaner or a lawnmower. The greenhouse frog’s call is a quiet “trill” which you can only hear with a couple feet of the frog.


Coqui frogs may reach population densities of up to 10,000 per acre. At this density, the male frogs seem to compete with each other as their calls build in volume. The result is a cacophony of overlapping calls which would turn our peacefully nighttimes into a raucous, sleep-invading jamboree.


Mac Lowson, president of the Hawaii Association of Realtors on Oahu was quoted as saying “I would rather live next to a highway than live next to an area that has the coqui frogs. The coqui frog (sound) is a shrill shriek and then silence.”


Recent attempts to prevent the spread of the coqui frog have met with some success. The population at the Iwilei Home Depot seems to have been eradicated. That meant removing a thick groundcover near the store's parking garage. At least 16 coqui frogs and more than 100 greenhouse frogs were captured there, many of the coqui were caught as the plant cover was removed. After denuding the area, a chemical treatment of citric acid was applied.


Chemical treatments which have been used include concentrated caffeine, hydrated lime, and the afore-mentioned critic acid. In the last year, plant importers have been using hot water to eliminate the frogs and their eggs on plant shipments.


Oahu's biggest colony of coqui frogs in Wahiawa recently was brought under control with the help of the Oahu Invasive Species Committee and the state Department of Land and Natural Resources. A crew has been spraying citric acid three to four times a week for the past year, according to Scott Williamson, with Forestry and Wildlife.


In Haiku, lot size and the moist environment are two major risk factors for a Coqui infestation. Coquis love plants with large leaves such as heliconia, bananas, false stag horn fern (uluhe), wild orchid, ginger, and our yellow creeping daisy (Wedelia trilobata).


Besides the nighttime disturbance, coqui frogs can wipe out beneficial insects (they don’t eat mosquitoes, but love many insects which prey on mosquitoes). The frogs are also a preferred food for rats.


The television show “Outside Hawai'i” (OC16) has sought to educate the community about Hawaii’s invasive species and what we can do to prevent them from spreading. Shows dedicated to the Coqui frog infestation on the island of Hawai‘i have aired. Howard Lontoc, Coqui Community Coordinator for Hawai`i County warns that “if other communities are not extremely careful, the same could happen elsewhere. Even if you hear just a few frogs, it’s time to take action”.


The action needed would depend on the severity of the problem. Spraying critic acid and/or hydrated lime may work. There are traps which have been employed effectively in some locations. But to completely wipe out a population would probably require more dire measures like removing all plants and bushes within the infested area and then spraying repeatedly over the course of several weeks.


In the case of coqui frogs, clearly an ounce of prevention is worth a ton of cure -- be careful where you buy plants for your backyard. Check with the nursery or better yet the Hawaii Department of Agriculture for recent outbreaks on Oahu.


Most importantly, don’t bring plants, flowers or anything which could harbor coqui frogs or eggs back from neighbor islands. This is especially true with the start of service to neighbor islands via the Superferry.

If you hear a loud “KO KEE” two-tone call during evening hours, you can look for the coqui by using a flashlight to locate the frog, capture it by hand (the coqui is non-toxic) or use a jar with a lid to contain the animal. Then call the State's Toll-Free PEST HOTLINE at 643-PEST (7378).

Undoubtedly if a small number of coqui frogs were able to gain access to our backyards, the resultant population explosion would severely alter the night-time peacefulness of our neighborhood. Let’s keep Haiku Coqui free!

For more information, contact:

Hawaii Department of Agriculture

Office of the Chairperson

1428 S. King Street

Honolulu HI 96814

Ph: 808 973-9560

Email: hdoa.info@hawaii.gov

References:

http://hawaii.gov/hdoa/meetings_reports/legislative-reports/2007LegReports/2007%20Coqui%20Report.pdf

http://honoluluweekly.com/cover/2006/08/snakes-on-a-plane-2/

http://starbulletin.com/2001/05/16/news/story4.html

http://starbulletin.com/2002/12/15/news/story6.html

http://starbulletin.com/2007/02/27/news/story04.html

http://starbulletin.com/2007/03/01/editorial/editorial01.html

http://the.honoluluadvertiser.com/article/2004/Mar/29/ln/ln17a.html

http://the.honoluluadvertiser.com/article/2006/Jan/29/ln/FP601290348.html

http://www.ctahr.hawaii.edu/coqui/index.asp

http://www.ctahr.hawaii.edu/coqui/lime.asp

http://www.ctahr.hawaii.edu/coqui/population.asp

http://www.ctahr.hawaii.edu/coqui/refugia.asp

http://www.fs.fed.us/r8/caribbean/natural-resources/related.shtml

http://www.hawaii.gov/hdoa/pi/pq/coqui/?searchterm=coqui%20frog

http://www.hear.org/AlienSpeciesInHawaii/species/frogs/lotsafrogs-short.wav

http://www.hear.org/kisc/pdfs/20070824coquinews.pdf
http://www.malamahawaii.org/news/malama_news.html


Coqui Frogs Would Love Haiku