Puerto Rican Parrot
Puerto Rican Parrot
|Listed||March 11, 1967|
|Description||Green parrot with red forehead and blue wings.|
|Food||Fruits, seeds, and leaves.|
|Reproduction||Clutch of four eggs.|
|Threats||Habitat destruction, collectors.|
The brightly colored Puerto Rican parrot, Amazona vittata, is about 12 in (30 cm) long. It is mostly green with a red forehead, blue wing feathers, and peach-colored bill and feet. It is closely related to the Jamaican black-billed parrot (A. agilis ) and the Hispanolian parrot (A. ventralis ).
Puerto Rican parrots, which reach sexual maturity at three to five years, form stable pair bonds. Mates stay together throughout the year, except when the female is nesting. The male then assumes full foraging duties. The Puerto Rican parrot is a deep forest bird that nests in tree cavities and tends to use the same tree year after year. The female lays from two to four eggs, which she incubates for about 26 days. Young parrots hatch nearly naked and with closed eyes. After about a week, the female resumes foraging duties with her mate, browsing on fruits, seeds, and leaves for part of the day. Chicks fledge at about nine weeks of age.
As of the late twentieth century, the habitat of the parrot is sheltered deep within the largest remaining area of essentially unmodified forest on Puerto Rico. The parrot is critically dependent on mature, large-diameter trees to provide cavity nesting sites that have been in continuous use for decades. The tabonuco tree (Dacryodes excelsa ), used both as a nesting site and as a food source, grows mainly at elevations below 2,000 ft (610 m). Laurel sabino (Magnolia splendens ) and nuez moscada (Ocotea moschata ) grow in the upper forests now used by the parrots. The primary nesting tree in recent decades has been the palo colorado (Cyrilla racemiflora ). This habitat is not the parrot's preferred one. When lowland habitat was destroyed, parrots retreated to the upper forest area. Although parrots previously migrated seasonally to lowland forests, they now seldom leave the western edge of the forest to forage in the lowlands and are restricted to the sierra palm and palo colorado zones in the Caribbean National Forest.
This parrot was once abundant on the island of Puerto Rico and was also found on the islands of Culebra, Vieques, and Mona. Historic population figures are highly speculative, but may have exceeded one million birds. The population probably remained reasonably stable until the sixteenth century when European settlement began. By the early twentieth century the species had disappeared from all of the offshore islands and was restricted to five known areas on the mainland of Puerto Rico. By about 1940 the only remaining population was in the Luquillo Mountains, including the Caribbean National Forest of eastern Puerto Rico, the largest area of remaining native vegetation. In 1989 fewer than 100 parrots survived—about 43 in the wild and 52 in captivity. By 1994, estimates were down to about 40 birds in the wild. The U. S. Fish and Wildlife Service operates an aviary in the Luquillo Mountains rain forest, which has had success in breeding the birds in captivity. Although facilities were severely damaged by hurricane Hugo in 1989, production the year following the hurricane was normal; 37 eggs were produced and five young fledged. In 1992, 38 eggs were produced and two hatched. One of the 1992 hatchlings was taken from the aviary and successfully fledged in the wild, the first such event since the mid-1980s. Unfortunately, the other 1992 hatchling died.
The destruction of the island's native forests has been the major factor in the historic decline of the Puerto Rican parrot. By 1912 the island was more than 80% deforested; and by 1922 only about 20,000 acres (8,100 hectares) of the Luquillo Mountains remained forested. In the last decades of the twentieth century, the forests revived. By 1990, more than 40% of the island was wooded, and woodland acreage had doubled in the Luquillo Mountains. But it will take many more decades for trees to mature to the point that they provide natural cavities for parrot nests. The Puerto Rican parrot suffers from both high rates of mortality and low reproduction. The habitat in the Luquillo Mountains has a much wetter climate than the parrot's historic range. Protection from rain is a major factor in choosing nest cavities. In addition, hurricanes can cause severe parrot decline, not only through physical battering, but also by destruction of nesting trees and damage to food supplies. In late 1989, hurricane Hugo battered the eastern end of Puerto Rico. Surveys taken following the storm indicated that only about half of the island's wild parrots survived. Daily counts varied from a low of seven to a high of 23, indicating that the birds were moving around a great deal, probably in search of food. The hurricane also killed 22% of the palo colorado that were potential nesting trees in the eastern mountains. In August 1989, one month before hurricane Hugo, 47 Puerto Rican parrots were counted in the wild. Three months after the storm, only 20-22 parrots were seen, and only three breeding pairs were known to have survived. Traditional foraging areas may have been devoid of food after the hurricane, which struck before the parrot's winter breeding season. In 1990 breeding activity was low; three pairs nested, but only one pair successfully fledged young.
Beyond the immediate damage done by Hugo, however, researchers were delighted to note a gradual and surprising increase in the parrot population, and some believe the hurricane disturbance may have ultimately helped the species. In both 1991 and 1992, the wild flock of Puerto Rican parrots produced a record six successful nests each year, the highest number since the 1950s. In 1991, six pairs nested in the wild and produced 20 eggs, 10 of which hatched. Of the 10 nestlings, two were poorly developed and died. All but one of the eight surviving nestlings fledged successfully. The 1991 production of seven fledged parrots, however, was above the average for fledging prior to the hurricane. From 1987 through 1989, an average of five parrots fledged in the wild each year. In 1992, six pairs of parrots in the wild produced 18 eggs. The 15 eggs that hatched and the 10 nestlings that fledged were records. The average number of wild parrots fledged in 1991 and 1992 was 8.5, about 33% more than the average 1975-89 fledging rate. Expansion of the parrot's breeding range also occurred after hurricane Hugo. For the first time in recent record, a nest was found in the lower transitional forest of the Luquillo Mountains. All previously recorded parrot nest sites had been in the palo colorado life zone, a forest of higher elevation. Moreover, also for the first time in recent record, a natural cavity nest was discovered in a large tabonuco tree. When forests are disturbed by storms, however, more energy flows into reproduction and growth. Hurricane Hugo may have stimulated such activity in the parrot's current forest habitat. Thus, increases in clutch sizes and numbers of nests may result from the parrots' feeding on new growth that is high in the nutrients necessary for breeding—new growth stimulated by the hurricane's disturbance. Another possible reason for the increase in parrot productivity is that the hurricane forced parrots to disperse into the lowlands in search of food, which ultimately may have led them to discover new nesting sites. There may be enough nesting cavities for the parrot population in the short term; as the population increases, however, a shortage of nesting sites could develop. A hurricane even stronger and more devastating than Hugo may occur at any time and destroy more parrot nesting trees. Because it takes more than 660 years to produce optimum palo colorado trees for nesting parrots, and because there are no other areas in Puerto Rico with old-growth forests such as those of the Luquillo Mountains, growth of the parrot population could become limited by the supply of suitable nesting trees. Nest robbing by humans to obtain cage birds has been another major cause for parrot decline during the twentieth century. There is evidence that some nest cavities were cut open and nest trees were cut down to obtain nestling parrots. Parrots have also been shot as a crop pest and hunted as a game bird. The long-term, continual habitat decline is due to many interacting causes. Since recreational areas have been constructed in the Caribbean National Forest, there has been a dramatic increase in visitors to the area. Selective logging of mature trees has changed the character of significant areas of the forest.
Conservation and Recovery
The Puerto Rican parrot probably owes its continued survival to the fact that most of its remaining habitat is owned by the U. S. Forest Service. The Caribbean National Forest, comprising 27,846 acres (11,280 hectares) in the Luquillo Mountains, was declared a wildlife refuge in 1946. The Puerto Rico Field Station's Luquillo Aviary has collected a captive population of more than 52 birds, including six captive-bred chicks produced in 1989. In addition, biologists have "double clutched" two of the wild nests to increase egg production. This procedure involves removing the first clutch of eggs from a nest and transferring them to an incubator. The nesting female then lays a second clutch which she incubates. In 1987 this technique was used on two of the four active nests. The captive parrot flock will provide birds to establish a second wild population in the Rio Abajo forest on the western end of the island. Another approach to recovery is the possible alteration of the parrot's nesting habits. Research and management of potential nesting habitat may be able to expand the parrot's use of trees that are more common and widespread than palo colorado. Tabonuco and other large trees in Puerto Rico could provide nesting habitat if cavities in these trees suitable for parrot nesting are created or enhanced. With the successful management effort conducted by the U. S. Fish and Wildlife Service and the U. S. Forest Service, the parrot population could approach 80-100 individuals by the early twenty-first century. Encouraging new nesting traditions may be the key to increasing the population to 250 and achieving the goals of the Puerto Rican parrot recovery program.
U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345
U. S. Fish and Wildlife Service
Boquerón Ecological Services Field Office
P. O. Box 491
Boquerón, Puerto Rico 00622-0491
Telephone: (787) 851-7297
Fax: (787) 851-7440
U. S. Fish and Wildlife Service. 1987. "Recovery Plan for the Puerto Rican Parrot, Amazona vittata. " U. S. Fish and Wildlife Service, Atlanta.
Wiley, J. W. 1980. "The Puerto Rican Amazon (Amazona vittata ); Its Decline and the Program for Its Conservation." In Conservation of New World Parrots, edited by R. F. Pasquier. International Council for Bird Preservation.