Parrots in Peril?

Abstract

I was lying on a remote beach in Costa Rica near dusk, listening to the quiet surge of calm ocean waves. Insects maintained their dull, monotonous hum behind us in the tropical forest that bordered the beach. Suddenly, the peaceful air was disrupted as a flock of squawking, screeching birds flew into a nearby coconut tree. Caught without my binoculars and in the fading light, I could just discern approximately 15 or so green, conure-sized birds. Occasionally, a flash of orange, presumably from feathering underneath the wings, could be seen. After several minutes, these busy, boisterous birds disappeared just as suddenly as they had appeared. This was not my first, nor my only, encounter with wild psittacine birds during my brief visit to Costa Rica. However, it was one of the most memorable.

Like this flock of birds, which disappeared so suddenly, so are the rainforests rapidly disappearing. Tropical rainforest destruction, perhaps the most ecologically disastrous event in human history, is occurring at an alarming rate of 50 to 100 acres per minute! ,2 While occupying less than 7 % of the earth's land surface (a mere 2% of the globe), tropical rainforests provide a home for over one-half the world's species+,« To date, we have already lost one-half of the original tropical rainforests

Except for Australian cockatoos, one-fifth of all birds and plants on Earth evolved in the Amazon Basin? Through 65 million years of evolution, primary rainforest habitat represents the most biologically diverse and the most critically threatened habitat on the planet. Tropical rainforest, best defined by rainfall (160 to 400 inches) and temperature (approx. 80 °F), are located in areas of Central and South America, Indonesia, northeast Australia and west Africa. The Amazon holds, by far, the largest tract of rainforest. In addition to parrot species, tropical rainforests are the habitat for other common pet bird species such as toucans, lories and lorikeets.

While Australia maintains a population of many cockatoo species which are so abundant they are often shot as agricultural pests, a small tract of Australian rainforest is the sole habitat for a number of sensitive cockatoo and parrot species. Species dependent on this rare and important habitat include the Palm Cockatoo (Probosciger aterrimus), which was recently (1987) added to the CITES endangered species list. Other parrot species dependent on this rainforest include the Double-eyed Fig Parrot (Op ops it ta diopbtb alm a), Redcheeked Parrot (Geoffroyus geoffroyi) and the Eclectus Parrot (Eclectus roratus).

Species most sensitive to deforestation are those with limited distribution, specialized diets or specific habitat requirements. Such is the case for the Golden Parakeet or Queen of Bavaria Conure (Aratinga guarouba). The Golden Parakeet is found in a limited area in northern Brazil, south of the Amazon River. This species requires extensive stands of tall Amazonian rainforest during the nonbreeding season and cleared areas adjacent to the forest during breeding season. During both the breeding and nonbreeding season, these birds forage for food primarily in the tall forest. As a result of deforestation, species competition for habitat in the Golden Parakeet's range has developed? The Jandaya Parakeet (Aratinga solstitialis jandaya) utilizes the dried second growth which replaces the original rainforest habitat of the Golden Parakeet once it has been destroyed. Although the Golden Parakeet is protected as a threatened species in Brazil, pressures from largescale development, increased road access, increased value in the black market pet trade, as well as hunting pressure from local residents who either shoot the bird for meat or to rid their crops of pests, have resulted in rapid and widespread population declines in the eastern part of its range. Scientists David C. Oren and Fernando C. Novaes predict, as a result of a biological study conducted from 1981 to 1984, that unless measures are taken to secure a biological reserve for and alter domestic trade of this species, it is likely the Golden Parakeet will be extinct east of the Rio Tocantins by the year 2000.

Particularly susceptible species are island inhabitants, such as the St. Lucia (Amazona versicolor), Puerto Rican (Amazona vitto), Cuban (Amazona leucocepbala)and Saint Vincent (Amazona guildingii) Amazons. All large macaws are also particularly susceptible to tropical rainforest destruction. Although some parrot species have been studied extensively for habitat requirements, such as the Puerto Rican Parrot, no or limited information is available for breeding and natural habitat requirements for the vast majority of parrot species. Without this critical information, tracts of rainforest left standing could be of insufficient size or vital habitat requirements could be destroyed, dooming these species to extinction. Clearly, further field work is necessary in this area.

All Indonesian cockatoos require mature tropical rainfoest. In the Moluccas, where a growing human population has converted rainforests to cultivated land, 26 parrot species are known to occur. Species of cockatoos in Indonesia include the Salmonc rested (Cacatua moluccensis), Sulfur-crested (Cacatua galerita) and the Palm (Probosciger aterrinus) Cockatoos. In addition to population pressure, 90% of all Indonesia's tropical timber has been allocated to Japan. Faced with this type of onslaught, it is doubtful sufficient rainforest habitat will remain to accommodate the diversity of psittacine birds that currently exist in this area. Other species at risk due to rainforest destruction in Indonesia are the Black-lored Parrot (Tanygnathus gramineus), the Purple-naped Lory (Lorius garrulus) and the Amboina King Parrot (Alisterus amboinensis) to name a few.