T h e P u e r t t o R i i c a n P a r r r o t t
A m a z z o n a v i i t t t t a t t a
A r r e v i i e w o f f t t h e c u r r r r e n t t s s t t a t t u s s a n d o u t t l l o o k o n i i t t s s f f u t t u r r e
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Species Name
Scientific Name: Amazona vittata
Common Name: Puerto Rican Parrot
Historic and Current Ranges
The Puerto Rican parrot is presently found only in Puerto Rico, but until about 1899 it was also found on nearby Culebra Island. Earlier, it was found on Vieques and Mona
Islands as well. It may also have inhabited the Virgin Islands at the time of the arrival of the Spanish in 1493 (Snyder et al. 1987). 1 In Puerto Rico, the parrots were known to be in Guajataca Forest at medium elevation until 1910. In the Rio Abajo Forest, they were found also at medium elevations until the 1920s. In the Carite Forest, the parrot was found at high elevations until the 1930s 2 (The U.S. Forest Service estimated its population at this time to be about 2,000 birds (Wordsworth, 1949)). 1 In the swamp at the mouth of the Mameyes River it was found until 1927.
Since 1940, the range has been limited to the Caribbean National Forest in extreme eastern Puerto Rico. Although the Caribbean National Forest contains more than 26,000 acres, the parrots have concentrated in a small area of some 3,000 acres in the western and west central part of the forest (Rodriquez-Vidal 1959). 2
At the time of Columbus, the parrot’s total population may have exceeded 100,000 individuals. Some estimates are as high as 1,000,000 (Snyder et al., 1987; Wiley 1991).
In the 1950s, the population was estimated at 200 birds. In 1973, the population reached
1 an all-time low of 13 birds. By August 1989, the wild flock was numbered at 47, including 5 breeding pairs, although not all bred each year. As a result of Hurricane
Hugo, which hit eastern Puerto Rico hard on September 18, 1989, severely impacting the
Caribbean National Forest, the population was reduced. Currently there are about 24-26 parrots in the wild, including four breeding pairs. There are 56 in captivity at the Luquillo
Aviary. 2
Ecosystem and Habitat Needs
The present habitat consists of mature rain forest located between about 1,300 and 2,700 feet in elevation. Dwarf forest at the higher elevations and second growth lowland forest are not used. The parrots are confined to areas having the largest number of old colorado trees ( Cyrilla racemiflora ), which supply nesting cavities.
Historically, parrots occupied eight major climax or old-growth forest types (Little and
Wadsworth, 1964) that covered Puerto Rico and were interspersed only by small, scattered, sandy, or marshy areas near the coast (Snyder et al. 1987). 1 The parrots nested in holes in cliffs as well nesting cavities in trees, and occupied a more diverse habitat, particularly at lower elevations.
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General Life History, Characteristics, and Vulnerabilities
Birds do not mature and begin to successfully mate until they are 3 or 4 years old.
Typically they lay clutches of two to four eggs. The young fledge about 13 weeks after the eggs are laid. Breeding is limited by access to the preferred nesting sites. These are natural cavities found in Colorado trees. The nests are located between 7 & 15 meters above the ground.
The birds do not seems to be nearly as selective in their eating habits as they are in their breeding location habits. Threats caused by difficult access to food are not mentioned in the literature that was reviewed. As a protective mesure newly released captives are provided with feeding stations to augment their diet while fully acclimating.
There is no active “natural” dispersal of the population going on. There is a captive population that is being used to augment the wild population through a fairly successful captive breeding program and there are plans underway to establish a second population located in another area of Puerto Rico. Thus, any dispersal at this point will be driven by human effort. The population is so small and limited in breeding opportunities that if anything is on the parrots’ collective mind it is survival and not dispersal. It is believed, however, that they are blissfully ignorant of their precarious state!
Predators are a threat in the forest. These include rats and pearly-eyed thrashers. The thrashers pack a one-two punch since in addition to being predators they are also opportunistic egg layers who will lay their eggs in the nests of the parrots to be fledged by the parrot parents. When the baby thrasher hatches it is much larger and soon forces the parrot baby out of the nest or into starvation.
Other natural pressures are infestation of bot flies in the nestlings and the presence of honeybees. The bees create breeding pressure since they utilize the same cavities for their hives that the parrots use for their nests.
There is currently a captive breeding program underway. This is meant to serve several purposes. Primarily the goal is simply to increase the total number of birds in existence, the captive flock is also used to augment the total number of birds in the wild through release programs. In addition the captive populations serves the very important function of locating a second population in a second location to act as insurance against localized stochastic events. The value of this strategy was shown in 1989 when Hurricane Hugo hit
Puerto Rico and had a large impact on reducing the wild population. Lastly the captive population serves as a genetic reservoir for the metapopulation.
Main Human-induced Changes
Deforestation of their habitat, hunting, and the pet trade are the three main human activities that have contributed to this species becoming endangered.
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Of the three, deforestation had the biggest impact, leading to loss of food sources and nesting cavities for the parrot. Little habitat change occurred until the 200 year period of
1650-1850, when the local human population soared to almost 500,000 and clearing for agriculture eradicated forests (Wadsworth 1949). By 1900, the human population had doubled to a million. About 76% of the land had been converted from forest to agriculture
(Snyder et al. 1987). After 400 years of European civilization, less than 1% of old-growth forest remained. 1 This rapid decline of habitat was the most important driver in the tremendous decline of the original metapopulation.
Important Threats
Given the small size of the remaining population of Puerto Rican parrots, all adverse pressures are very serious.
2 Any threat to the population is an important one.
In addition to the human generated threats described above, the Puerto Rican parrot faces additional threats from natural predators: the black rat ( Rattus rattus ), the pearly-eyed thrasher ( Margarops fuscatus ) and the red-tailed hawk ( Buteo jamaicensis ). The pearlyeyed thrasher, whose population has grown more abundant and widespread in recent years, also competes with the Puerto Rican parrot for suitable nesting cavities, an additional source of pressure.
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Competition arises from honey bees ( Apis mellifloris ) for nesting cavities that they utilize to build their hives.
Particularly severe hurricanes in 1898, 1928, 1932, and 1989 reduced the small, isolated parrot populations further.
Bot fly ( Philornis spp.) infestations pose a minor problem to nestlings.
Introduced parrots and parakeets are common in Puerto Rico and could pose a threat if they expand their ranges into older forests, introducing diseases and competing for resources.
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Specific Vulnerabilities
The primary vulnerability the birds have today is the infinitesimal size of the wild and of the total population. A single misadventure could finish them for good. A single storm, a fire or disease could either wipe out or harm the population in an inordinate way.
Beyond that is their most important vulnerability is the dependence on very specific nesting sites. Because of the deforestation caused by agriculture and other human development activities the areas that have the required sites are quite limited. This dependence also makes them more sensitive to competitive pressures from other birds,
(thrashers, introduced parrots), and honeybees.
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Because the birds are not able to breed until they are between 4 & 5 years old the delay in their maturity rate (as an absolute, not as compared to other birds) is a limiting factor in the speed of recovery and growth rate of the population.
The birds are also sensitive to the severely disruptive effects of low-flying planes over the area. Over the past seven years scientists have observed that they can thwart breeding and nesting. Although rules are in place to keep planes out of the area and aviation charts are annotated to restrict flight, but both civilian and military aircraft have flouted the ban.
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Current Conservation Actions and Recommendations for Species Recovery
Efforts to protect and restore the population of Puerto Rican parrots began in 1968 with the commencement of a captive program made up of wild parrots and several in captivity.
At that time the population stood at 24. In 1975 it reached an all-time low of 13.
Subsequently it climbed to 47 in 1989 when Hurricane Hugo did catastrophic damage. In the early 1990s the population stood at 24 in the wild with 56 in captivity, and by 2000 had reached 40 in the wild, with 112 in captivity. The sizable captive population can also provide different genetic stock for exchange with the wild population. Since the disaster of Hurricane Hugo, part of the program has been designed to establish two separate populations of birds as a hedge against destruction. Drawing on captive-bred populations in recent years, the team has performed several successful reintroductions.
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In the past quarter century research teams have intensively investigated the habitat of the
Puerto Rican parrot, particularly nesting and predators. Black rats and pearly-eyed thrashers have been identified as predators and subject to control. Honey bee swarms and bot fly infestations injurious to nestlings have also been controlled. Captive bred young have been introduced into wild nests. Nests have been guarded and maintained, and enhanced nesting cavities have been created.
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The Recovery Plan for the Puerto Rican Parrot, Amazonas vittata, (approved April 1987) has recommended the following actions:
1.
Increase effective wild population at the Caribbean National Forest to a selfsustaining level of 500 birds.
2.
Maximize production of Puerto Rican parrots in captivity for eventual release.
3.
Protect and improve present and potential parrot habitat within the Caribbean
National Forest Area and the Rio Abajo area.
4.
Establish and maintain a second aviary at Rio Abajo Forest to produce parrots for release.
5.
Manage wild populations in the Caribbean National Forest and in the Rio Abajo area.
6.
Construct and operate a second aviary at Rio Abajo Forest to produce parrots for release.
7.
Encourage research and recovery efforts by reputable members of the private sector.
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Action Steps to Aid Recovery of the Species
This is the first animal to be listed as endangered on the Federal Register. As the recipient of such a dubious honorific it could be argued that any and all activities undertaken to save the species fall into the “absolutely necessary and critical” category. To lose the first listing would be a negative that would be hard to recover from emotionally and politically
(providing ammunition to those who might argue that our efforts to save highly endangered species is ineffective and wrong headed).
With the understanding that there are many species who need our attention and that resources (human, financial, and scientific) are always limited, we list the following steps for a program of recovery:
Absolutely Necessary & Critical
 Set the goal: To increase effective wild population of Puerto Rican parrots at the
Caribbean National Forest to a self-sustaining level of 500 birds by 2010
 Create benchmarks to measure incremental successes in moving towards goal via efforts below.
 Continue captive breeding programs
 Continue the development of a second aviary at Rio Abajo Forest to produce parrots for releas
 Continue and expand release programs, reintroduce into new locations
 Design and develop alternative nesting sites
 Continue to monitor and control competition, predation, and disease vectors
 Resolve the overflight problem
 Improve enforcement of existing regulations
 Continue outreach to educate public of the efforts underway, particularly with the goal of fundraising for the Puerto Rican parrot conservation efforts.
 Write grants to generate additional funding for the above efforts.
 Develop a plan and a time line to send small numbers of the population to zoos and other research facilities for additional breeding efforts as well as location stochasticity insurance. Although there are now three different locations (two captive and one wild), they are not dispersed enough to guarantee survival in the event of a
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catastrophe (i.e., hurricane, major disease outbreak) given the extreme vulnerability of the species.
 Explore ways to get the parrots to adapt to their former habitat at various elevations on the islands of Puerto Rico, Culebra, Vieques and Mona; Guajataca Forest, Carite
Forest, and the swamp at the mouth of the Mameyes River.
Important Support but Not Immediately Critical
 Community education – encourage development of backyard nesting sites to provide nesting sites for the stray couple that may pass by. Although highly unlikely to happen it will increase awareness and people will naturally begin to feel proprietary about the species.
 Increase potential nesting sites by increasing protected land. This may be possible since agriculture is becoming less and less of an important industry in Puerto Rico.
This may be critical to long term survival but not to the short term issues.
1 Puerto Rican Parrots, Michael J. Meyers, http://biology.usgs.gov/s+t/noframe/b016.htm
(3 Nov. 2002)
2 Puerto Rican Parrot, Amazona vittata , U.S. Fish & Wildlife Service, http://www.tld.net/users/fconserv/PRParrot.htm (3 Nov. 2002)
3 U.S. Fish and Wildlife Service Puerto Rican Parrot, http://endangered.fws.gov/birds2.html (4 Nov. 2002)
4 Low-altitude flights endanger rare parrot, Environmental Network News, http://www.enn.com/enn-news-archive/1998/06/062298/parrot.asp (3 Nov. 2002)
Puerto Rican Parrot Release, U.S. Fish and Wildlife Service (Adobe Acrobat pdf document, undated), http://southeast.fws.gov/pubs/facts/PR_parrot_release.pdf (5
Nov. 2002)
Little E.L. Jr. and F.H. Wadsworth, 1964. Common trees of Puerto Rico and the Virgin
Islands (reprint). Agriculture Handbook 249. U.S. Department of Agriculture,
Washington, DC. 556 pp.
Rodriguez-Vidal, J.A., 1959.
Puerto Rican parrot study. Monographs of the Department of
Agriculture and Commerce1. San Juan, Puerto Rico. 15 pp.
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Snyder, N.R.F., J.W. Wiley, and C.B. Kepler, 1987.
The parrots of Luquillo: natural history and conservation of the Puerto Rican parrot. Western Foundation of
Vertebrate Zoology, Los Angeles, CA. 384 pp.
Wadsworth, F.H., 1949.
The development of the forested land resources of the Luquillo
Mountains, Puerto Rico. Ph.D. dissertation, University of Michigan, Ann Arbor. 481 pp.
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