Puerto Rican Parrots

By J. Michael Meyers National Biological Service Since the arrival of Columbus in Puerto Rico, the Taino Indian hasdisappeared and the parrot has just barely survived (Wadsworth 1949;Snyder et al. 1987). The Puerto Rican parrot (Amazona vittata) hadshared its habitat with the peaceful Taino Indians for centuriesbefore the arrival of European settlers in the Caribbean.Status and TrendsUpon arrival of the Spanish in 1493, the Puerto Rican parrot lived inall major habitats of Puerto Rico and the adjacent smaller islands ofCulebra, Mona, Vieques, and possibly the Virgin Islands (Snyder etal. 1987). Parrots occupied eight major climax or old-growth foresttypes (Little and Wadsworth 1964) that covered Puerto Rico and wereinterspersed only by small, scattered, sandy, or marshy areas nearthe coast (Snyder et al. 1987). Parrots nested in cavities of largetrees that were plentiful throughout the forests. Fertile, moistlowland forests in the coastal plain as well as forested mountainvalleys contained much of the fruits and seeds necessary to feed athriving parrot population. The forests of Puerto Rico probablysupported a parrot population of 100,000-1,000,000 at the end of the15th century (Snyder et al. 1987; Wiley 1991).Fig. 1. Population trends of humans and Puerto Rican parrots since1500 (Snyder et al. 1987 and U.S. Census data; all data for the year2000 are projected). Populations are converted to log10 for showingtrends.Little habitat change occurred in Puerto Rico during the first 150years of European settlement. By 1650 the Spanish population hadincreased to 880 (Snyder et al. 1987); parrots still occupied allmajor habitats and were plentiful (Fig. 1). During the next twocenturies the human population soared to almost 500,000 (Fig. 1), andclearing for agriculture, especially in the lowlands, eradicatedforests in Puerto Rico (Wadsworth 1949). By 1836 reports by Moritz, aGerman naturalist, indicated that the Puerto Rican parrot populationhad begun to decline (Snyder et al. 1987).Puerto Rican parrot (Amazona vittata). Courtesy J.M. Meyers, NBSBy 1900 the human population had doubled to a million (Fig. 1).About 76% of the land area of Puerto Rico had been converted fromforest to agriculture (Snyder et al. 1987); less than 1% of the old-growth forest remained after more than 400 years of Europeancivilization. At this time, the parrot population must have been low,but no data exist. By 1937 U.S. Forest Service (USFS) rangersestimated the Puerto Rican parrot population at about 2,000 birds(Wadsworth 1949). A few years later, parrots were found only in theLuquillo Mountains, formerly a forest reserve of the Spanish Crownand now managed by the USFS. This area contained the last foresthabitat suitable for Puerto Rican parrots.Fig. 2. Population trends of the Puerto Rican parrot in the 20thcentury.Population surveys of the Puerto Rican parrot were not conducteduntil the 1950's. Early estimates of the parrot population in PuertoRico are based on few written records and general observations(Snyder et al. 1987), knowledge of the parrot's biology, andextrapolation of population surveys conducted by Rodríguez-Vidal(1959). During the 1950's, Rodríguez-Vidal of the Puerto RicoDepartment of Agriculture and Commerce conducted the first extensivestudy of the Puerto Rican parrot. He reported a population of 200Puerto Rican parrots by the mid-1950's (Fig. 2). About 20 years laterthe population had dwindled to 14 individuals that inhabited anisolated rain forest of the Luquillo Mountains.In 1968 Kepler, U.S. Fish and Wildlife Service (USFWS), organizedparrot surveys by placing observers at strategic sites, includingoverlooks from prominent rocks, road-cuts, and building roofs. Snyderet al. (1987) improved the survey method in 1972 by constructing 10treetop lookouts in areas of major parrot use. Parrot surveys areconducted from these platforms during the breeding season and pre-and postbreeding season (Snyder et al. 1987). Observers collectinformation on parrot numbers, directions, and their distance fromthe platform by the time of day. By 1993 this treetop lookout systemwas expanded to 38 platforms (Vilella and García 1994).In 1968 implementation of the Puerto Rican Parrot Recovery Planbegan; it is a cooperative effort of scientists and managers of thePuerto Rico Department of Environmental and Natural Resources, USFS(Caribbean National Forest and International Institute of TropicalForestry), USFWS Puerto Rican Parrot Field Office, and the NationalBiological Service. After the recovery program began, the parrotpopulation increased to 47 birds by 1989 (Wiley 1980; Lindsey et al.1989; Meyers et al. 1993); however, about 50% of the population wasdestroyed by Hurricane Hugo that same year. A small population of 22-24 individuals remained in late 1989 (Fig. 2). Since then, thepopulation recovered to 38-39 by early 1994 (F.J. Vilella, USFWS,personal communication). After the hurricane, the number ofsuccessful nesting pairs increased from a maximum of 5 to 6 pairsfrom 1991 to 1993 (Meyers et al. 1993; Vilella and García 1994).Research and ManagementPuerto Rican parrots declined in relation to the increasing humanpopulation (Fig. 1). Conversion of forests to agriculture and loss offorest habitat, on which the species depended for food and nestcavities, was the primary cause for decline. Shooting parrots forfood or protection of crops and capture for pets were secondarycauses for decline. The remnant parrot population in the LuquilloMountains was further stressed when trails and roads were created andwhen human uses of the forest timber were encouraged in the early1900's (Snyder et al. 1987). Storms before the arrival of Europeansprobably had little effect on the parrot population because thepopulation was more widespread, and hurricanes tend to affect only asmall geographic area. Severe hurricanes in 1898, 1928, 1932, and1989 reduced small, now-isolated populations even further. Theapparent ability of the population to rebound after these storms issuggested by increases in the parrot population and in nesting pairsafter Hurricane Hugo hit the island in 1989 (Meyers et al. 1993).Intense research and management strategies during the last 27 yearshave prevented the extinction of the Puerto Rican parrot. Much of theeffort to rebuild the population has involved research and managementof nesting sites (Wiley 1980; Snyder et al. 1987; Lindsey et al.1989; Wiley 1991). Predators, such as black rats (Rattus rattus) andpearly-eyed thrashers (Margarops fuscatus), have been controlled(Snyder et al. 1987). Bot fly (Philornis spp.) infestations ofnestlings are still a minor problem (Lindsey et al. 1989). Managementof nests by fostering captive-reared young into wild nests, guardingnests, controlling honey bees (Apis mellifera), improving andmaintaining existing nest cavities, and creating enhanced nestingcavities should increase the population of the Puerto Rican parrot(Wiley 1980; Lindsey et al. 1989; Wiley 1991; Lindsey 1992; Vilellaand García 1994).Hurricanes will continue to threaten the wild population of thePuerto Rican parrot. Researchers estimate that storms equal to theintensity of Hugo (sustained winds of 166 km/h or 104 mi/h) occur atleast every 50 years in northeastern Puerto Rico (Scatena and Larsen1991). The risk of extinction caused by hurricanes will be reduced byestablishing a geographically separated wild population (USFWS1987).Introduced parrots and parakeets are common in Puerto Rico, includingsome of the genus Amazona. Monitored populations of these non-nativebirds have increased from 50% to 250% during 1990-93 (J.M. Meyers,National Biological Service, unpublished data). If they expand theirranges to include older forests, these populations may pose a threatto the Puerto Rican parrot by introducing diseases and by competingfor resources. At present, none of the introduced Amazona populationsare found near the Luquillo Mountains; however, orange-frontedparakeets (Aratinga canicularis) have foraged and nested in thesemountains at lower elevations (J.M. Meyers, NBS, unpublished data).As the Puerto Rican parrot population increases, it is possible thatsuitable nesting sites may limit population growth. Before thisoccurs, research and management should concentrate on increasing thewild population. The ability of the Puerto Rican parrot to expand itspopulation in a manner similar to the exotic parrots in Puerto Rico,in a variety of natural and human-altered environments, should not beunderestimated and may be the key to its recovery.For further information:J. Michael MeyersNational Biological ServicePatuxent EnvironmentalScience CenterPO Box NPalmer, Puerto Rico 00721-0501 USA--------------------------------------------------------------------------------ReferencesLindsey, G.D. 1992. Nest guarding from observational blinds: strategyfor improving Puerto Rican parrot nest success. Journal of FieldOrnithology 63:466-472.Lindsey, G.D., M.K. Brock, and M.H. Wilson. 1989. Current status ofthe Puerto Rican parrot conservation program. Pages 89-99 in Wildlifemanagement in the Caribbean islands. Proceedings of the FourthMeeting of Caribbean Foresters. U.S. Department of Agriculture,Institute of Tropical Forestry, Río Piedras, Puerto Rico.Little, E.L., Jr., and F.H. Wadsworth. 1964. Common trees of PuertoRico and the Virgin Islands (reprint). Agriculture Handbook 249. U.S.Department of Agriculture, Washington, DC. 556 pp.Meyers, J.M., F.J. Vilella, and W.C. Barrow, Jr. 1993. Positiveeffects of Hurricane Hugo: record years for Puerto Rican parrotsnesting in the wild. Endangered Species Tech. Bull. 27:1,10.Rodríguez-Vidal, J.A. 1959. Puerto Rican parrot study. Monographs ofthe Department of Agriculture and Commerce 1. San Juan, Puerto Rico.15 pp.Scatena, F.N., and M.C. Larsen. 1991. Physical aspects of HurricaneHugo in Puerto Rico. Biotropica 23:317-323.Snyder, N.R.F., J.W. Wiley, and C.B. Kepler. 1987. The parrots ofLuquillo: natural history and conservation of the Puerto Ricanparrot. Western Foundation of Vertebrate Zoology, Los Angeles, CA.384 pp.USFWS. 1987. Recovery plan for the Puerto Rican parrot, Amazonavittata. U.S. Fish and Wildlife Service, Atlanta, GA. 69 pp.Vilella, F.J., and E.R. García. 1994. Post-hurricane management ofthe Puerto Rican parrot. In J.A. Bissonette and P.R. Krausman, eds.International Wildlife Management Congress Proceedings. The WildlifeSociety, Washington, DC. In press.Wadsworth, F.H. 1949. The development of the forested land resourcesof the Luquillo Mountains, Puerto Rico. Ph.D. dissertation,University of Michigan, Ann Arbor. 481 pp.Wiley, J.W. 1980. The Puerto Rican parrot (Amazona vittata): itsdecline and the program for its conservation. Pages 133-159 in R. E.Pasquier, ed. Conservation of new world parrots. InternationalCouncil for Bird Preservation Tech. Publ. 1. Smithsonian InstitutePress, Washington, DC.Wiley, J.W. 1991. Status and conservation of parrots and parakeets inthe Greater Antilles, Bahama Islands, and Cayman Islands. BirdConservation International 1:187-214.