The Coqui Frog (Eleutherodactylus coqui)

Originally published in The Manitoban, 2011

             

This week I have been bitten by fire ants, termites and a cactus. Now I've got all that out of the way, I hope to spend the rest of my stay in glorious Puerto Rico in perfect harmony with nature. I would especially like to harmonize with the common coqui frog, Eleutherodactylus coqui. They have a very pretty song.

            

While I have not yet seen one, they are the first thing I heard when I set foot on this fascinating island. Male coquis start singing as soon as the sun begins to set, currently around 6pm, and they continue singing until the sun comes up around 6:30am. Males sing to advertise to females and announce their territory to other males.

            

Named onomatopoeically for their song (ko-kee, ko-kee), the coqui belongs to the genus Eleutherodactylus, a long Greek name lending itself to over 600 species, meaning “free toes”. This refers to the fact that members of this genus do not have webbed feet, but have individual and unattached toes with large pads adapted for climbing. As you might guess, coqui frogs are arboreal, climbing trees as the sun sets to hunt insects until dawn, at which time they retreat to their hide-outs for the day. Just like teenagers and goths.

            

Coqui frogs are very small, ranging from 15 to 80mm in length. In fact, coqui means “little frog”. Unlike most frogs, fertilization is internal and coquis do not lay their eggs in water but terrestrially in moist areas. The young develop within the egg over a period of about 17 to 26 days and hatch as miniature adults with very small tails that disappear shortly after hatching. The tadpole stage occurs within the egg so there is no free-living larval stage as in most frogs. There are also developmental differences; some of the stages that free-living tadpoles pass through are absent in the coquis.

           

Coquis reproduce year-round but the majority of breeding takes place during the rainy season from about September to December. Male coquis guard the eggs and remain at the nest for the first few days after their eggs hatch, but by that time, the females are long gone. Females usually lay between four and six clutches of anywhere from 16 to 41 eggs per clutch – with a schedule like that, it's no wonder she doesn't stick around!

            

For the taxonomically inclined, coquis belong to the order Anura and family Leptodactylidae. In Puerto Rico there are 17 species of coqui frog; however, only two of them actually have the 'ko-kee' song for which they are named. Three species of coqui, web-footed, mottled and golden, are believed to be extinct. The golden coqui, E. jasperi, is (was?) the only member of the family Leptodactylidae that gives birth to live young.

            

Common coquis are found on St. Croix, St. John and St. Thomas, U.S. Virgin Islands, Dominican Republic, Vieques, and Florida. They are considered an invasive species in Hawaii, where efforts to eradicate the little guys are under way. The common coqui is doing quite well on the island of Puerto Rico, and Puerto Ricans like it that way – the coqui symbol is used by many local businesses and institutions and is advertised as a source of local pride.

            

In fact, in my tireless efforts to bring you only the most well-informed articles, I drove all the way to Rincon to check out an Oktoberfest (yeah, I know, right?) celebration sponsored by one of Puerto Rico's two local breweries, Old Harbor Brewery based in San Juan, so that I could sample their Coqui Lager. Coquis are great, but I liked the pale ale better. At that point, I didn't know what animal that ale was named after, but there is a Puerto Rican boa that's endangered, so stay tuned next week for the low down on that lovely creature.

              

The Puerto Rican Parrot (Amazona vittata)

Originally published in The Manitoban, 2012

The Puerto Rican Parrot (Amazona vittata) is the only endemic parrot species in Puerto Rico. The Taino Indians referred to this parrot as Higuaca or Iguaca (the "h" is silent), and so shall I throughout this article.

Higuaca are about 12 inches long. They are emerald green with blue primary feathers, a white eye ring, red forehead and a short, blunt tail. The Hispaniolan Parrot (Amazona ventralis), an introduced species, are often mistaken for Higuaca.

            

Higuaca reach sexual maturity between three to five years of age and form long-lasting pair bonds. Pairs remain together year round, breeding once a year during the dry season (February to June). Females incubate the eggs while males forage for themselves as well as for the incubating female. Both parents feed the chicks. Once fledged, the young (two to four on average) remain with the parents for several months or even into the next breeding season.

            

Higuaca are primarily frugivorous (fruit eaters) and live in the old-growth rainforests of Puerto Rico. Unfortunately very little rainforest remains, as most of it has been cut down to make way for agriculture. Yes that's right folks, that old beast habitat loss through deforestation (via massive human population increase) is back to haunt us again in this, the last Puerto Rican edition of Zoological Investigations.

            

Higuaca are one of the most endangered birds in the world today. Back in the 1400s, the Higuaca population was estimated at anywhere from 100 000 to one million (based on field observations). Spanish colonization in the 1600s led to massive human population increases and  deforestation. This drastically diminished the amount of suitable habitat and Higuaca numbers were reportedly declining as early as 1836.

            

By 1900, the human population on the island was about 1 million. About 76% of the forest had been converted to agriculture and less than 1% of the old-growth forest remained. In 1937 the Higuaca population was estimated at only 2000 individuals and could only be found in the Luquillo Mountains, the last suitable habitat available to these beautiful parrots. Rigorous population estimates were carried out in the mid-1950s (200 birds) and in the late-1960s the estimate was reduced to 14! Imagine trying to find a date (let alone start a family) with only 13 people to choose from, roughly 50% of which were the wrong sex for procreation. Ouch, hey?

            

Finally, in 1967 the Higuaca were declared endangered and in 1968 the Puerto Rican Parrot Recovery Plan was initiated. This was a joint effort of the Puerto Rico Department of Environmental and Natural Resources (DNR), the Caribbean National Forest and International Institute of Tropical Forestry (USFS), the United States Fish and Wildlife Service (USFWS) Puerto Rican Parrot Field Office and the National Biological Service. A captive breeding program was set up in 1987 and by 1989, the wild population had increased from 14 to 47 birds. Great news, right? Well, it's tough love in the jungle and in the same year, Hurricane Hugo wiped out about 50% of the slowly recovering population.

            

If I might detour away from habitat loss for a paragraph, Higuaca are also threatened by the introduction of exotic parrots such as parakeets and other species of amazon parrot. This includes birds that were introduced into the wild on a large scale in the past ("Hey, parrots are cool, let's get more!"), as well as by pet owners who release domesticated birds into the wild (never, ever do that!). These birds compete (and often out-compete endemic species) for food and precious, scarce habitat. Higuaca have also been (and may still be) killed by collectors and farmers to prevent crop damage. They have also been caught for sale in the pet industry (never, ever buy wild-caught animals!).

            

Ongoing genetic research uses DNA fingerprinting to improve the parrots' genetic diversity. This is done by mating genetically distinct pairs to reduce inbreeding depression (reduced biological fitness as a consequence of breeding between closely related individuals). This is both difficult and important for species that have gone through severe  bottlenecks in which the population has become drastically reduced. This is an extremely important method used in reintroduction programs, often with great success. Yet for the Higuaca, another factor comes into play - “behavioural compatibility”. 

As I pointed out in the example of choosing a procreation partner from the last 6 or 7 humans on earth, Higuaca will not mate just because you throw them in a cage with a genetically distinct bird of the opposite sex. They have to actually like each other. Sucks for science, bonus for freedom of choice.

            

Currently, there are two captive breeding programs in Puerto Rico (Luquillo and Rio Abajo) that focus on maintaining a healthy, viable captive population and successfully reintroducing captive bred birds into the wild. The goal is to establish two free-living wild populations that will be stable at about 500 individuals each.

            

So, with all the thrill and bustle dedicated to the fight to save a beautiful, gregarious and intelligent animal such as the Puerto Rican Parrot, I think the Higuaca have a decent chance. Yet, I would like to point out that it does not always go so well for what we think of as ugly, useless, irritating, un-cuddly and/or anti-social species. I think it is important to remember that we are the most successful species currently inhabiting this planet and we are making life very, very difficult for most of the species we share this very limited space with. I think we should view ourselves as stewards of this environment and strive to repair the damages we have done to all of the species we have negatively impacted, not simply the pretty and cute ones we feel we can relate to! I am now done preaching. Stay tuned for more Z.I. coming to a Manitoban near you in January, 2012.

---          

For more on the Puerto Rican Parrot research, status, and conservation plans, see Brock and White (1992; http://www.pnas.org/content/89/23/11121.full.pdf) as well as the Puerto Rican Parrot Population Viability Analysis and Recommendations (IUCN; http://www.cbsg.org/cbsg/workshopreports/23/puerto_rican_parrot_pva_final_report_1989.pdf).

Photo courtesy of Mike Morel

Photo courtesy of Mike Morel