Puerto Rico Amazon
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Puerto Rican Amazon ( Amazona vittata ) |
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| ( Boddaert , 1783) |
The Puerto Rican Amazon ( Amazona vittata ) is an endemic species of parrot found only on the Caribbean island of Puerto Rico . It belongs to the genus of the Amazon parrots ( Amazona ) within the family of the real parrots (Psittacidae). Sometimes this species is also called an Iguaca. The Taínos gave it this onomatopoeic name because it reminds of the sound that the parrots make when they are blown up.
Since the extinction of the Carolina parakeet , the Puerto Rican Amazon is the only living species of parrot native to the territory of the United States occurs. With currently only a little more than 40 individuals, this Amazon is one of the rarest bird species in the world.
biology
The Puerto Rican Amazon is one of 32 species in the Amazon parrot genus . Two subspecies of it have been described so far. Amazona vittata vittata is the nominate form that is native to Puerto Rico and earlier probably also occurred on the islands of Vieques and Mona . The form has now died out there. The distribution area of the nominate form is limited today to the western areas of the Caribbean National Forest on Puerto Rico.
Amazona vittata gracilipes occurred on the island of Culebra . Since this species fed on bananas and other agricultural crops, it was hunted intensively and has beenextinctsince 1912 .
Appearance
As is typical for most Amazons, the Puerto Rican Amazon has a predominantly green fletching. These green feathers have a thin black border around the edge. The forehead of the birds is red and the eyes are surrounded by a wide white eye ring. The undersides of the wings, which are easy to see in flight, have a bright blue fletching. The tail feathers are yellowish green on the underside.
The body length of these amazons is between 28 and 30 centimeters, they weigh between 250 and 300 grams, with the birds generally weighing around 275 grams. Puerto Rico Amazons are relatively small birds compared to other species of the Amazons genus. However, the amazon species that occur in the Antilles are similarly small. As next of kin of the Puerto Rican Amazon on apply Jamaica living black-billed amazon ( Amazona agilis ) and on Hispaniola living Hispaniolan Amazon ( Amazona ventralis ).
As is typical of the Amazon parrots, the skull capsule in the Puerto Rican Amazon is complete. They also show the flight pattern typical of Amazons, in which the wing beats are soft and only reach their turning point below the body.
Stock development and distribution
When Christopher Columbus landed in Puerto Rico in 1493, the Puerto Rican Amazon was still a widespread and common parrot. The earliest population estimates differ widely. The earliest estimates speak of one million birds, while others put 100,000 individuals.
During the first 150 years under Spanish rule, population density in Puerto Rico was very low, and in 1650 , when the island was populated by about 880 people, the Puerto Rican Amazon was considered a common bird. After 1650, the population density on the island rose sharply and the population of the Puerto Rican Amazon began to decline. As early as 1836, the German natural scientist Heinrich Moritz Gaede stated that the number of individuals of this parrot species had decreased noticeably. In the second half of the 19th century , most of the original forest on Puerto Rico was cleared to allow the cultivation of sugar cane. This led to further declines in the population and on the smaller islands of Culebra, Vieques and Mona, which belong to Puerto Rico, the Puerto Rican Amazon was extinct at the beginning of the 20th century.
In 1940 the distribution of the species was limited to the Luquillo Mountains of the Caribbean National Forest . In the 1950s the population was only 200 individuals. The population decline continued over the next decades and reached its low point in 1975 with only 13 individuals. After that, the population began to recover slightly. In August 1989 the population was estimated to be at least 47 birds.
On September 18, 1989, Hurricane Hugo swept the northeast coast of Puerto Rico and wreaked havoc. The hurricane also caused severe damage to the endemic bird species in Puerto Rico. Two of the four remaining and isolated populations of the rare Puerto Rican wood warbler went out by the storm, and the population of the Puerto Rican Amazon was estimated at only 23 individuals after the storm. At the beginning of the 3rd millennium, the population had not yet reached the number before the storm. In 2006 the population was estimated at 44 individuals.
nutrition
Like all parrots, the Puerto Rican Amazon is a herbivore that consumes a wide range of food. It eats flowers, fruits, leaves, bark and nectar. Studies have so far found around 60 different food components for him. However, it is assumed that the food spectrum was even larger due to its larger distribution area. The food components currently used include the outer seed coat of Prestoea montana , Dacrycodes excelsa and Matayba domingensis , the fruits of Mardgravia sintenisii , Miconia sintenisii , Clusia gundlachil and Rheedia portoricensis ; the flowers of Alchornea latifolia and Pictocarpha tetrantha , the branches and leaves of Clusia grisebachiana , Magnolia splendens , Piptocarrpha tetrantha and Micropholis garciniaefolia as well as the bark of Psychotria berteriana and the buds of Inga vera .
Reproduction
The Puerto Rican Amazon breeds in tree hollows, which, however, are not dug by itself. The species mainly uses Cyrilla racemiflora as nesting trees . The trees Magnolia splendens and Dacryodes excelsa are also used as tree species, albeit to a much lesser extent than Cyrilla racemiflora . All of these tree species form tree hollows naturally. So that a lack of suitable nesting sites does not become a limiting factor in reproduction, artificial breeding caves have also been set up in the forest region where the Puerto Rican Amazon still occurs. These are accepted by the birds.
The nests are usually between 7 and 15 meters above the ground. The males are usually the ones looking for suitable nesting holes. As soon as a suitable breeding site is found, the couple spends some time inspecting and cleaning the tree hole. No nesting material is introduced into the brood cavity.
The Puerto Rican Amazon reaches sexual maturity in the wild at the age of 4 years; in captivity she is fertile at the age of three. Puerto Rican Amazons enter into a lifelong partnership. The breeding season falls between January and July when rainfall is low. The female lays between two and four eggs, which are incubated between 24 and 28 days. Only the female breeds. In contrast, both parents are involved in feeding the young. The young leave their nest 60 to 65 days after hatching. They live with the parent birds in the family unit until the beginning of the next reproductive period.
distribution
The Puerto Rican Amazon needs naturally grown forests with a high population of old trees because of their dependence on tree hollows. Neither the coppice forests that occur in Puerto Rico nor the reforested forest regions with regular tree felling can offer them sufficient living space. Today the distribution area is limited to 16 square kilometers at altitudes between 400 and 800 meters. This corresponds to only 0.2% of the previous habitat.
There is evidence that the Puerto Rican Amazon was not only common in Puerto Rico when Christopher Columbus landed, but also in the neighboring islands of Antigua and the Virgin Islands . Since the subspecies living on Culebra became extinct at the beginning of the 20th century, it can only be found on the main island of Puerto Rico and there, too, its range has gradually decreased in the course of the 20th century.
The main distribution area of the species was originally eight large, naturally grown forest areas with a high population of old trees. However, the species was also found in other habitats, provided that there were sufficient breeding caves available. The forest areas, which had a high population density of Puerto Rico Amazons, were distributed over the entire elevation profile of Puerto Rico. The Puerto Rican Amazon was found in the Guajataca State Forest until 1910 and in the Rio Abajo State Forest until 1920 , both forest areas at medium altitude. In the Carite State Forest, a wooded area in the mountainous region of Puerto Rico, it was observed until the 1930s .
Natural enemies
The red-tailed buzzard ( Buteo jamaicensis ) is one of the natural enemies . The pearl-eye mockingbird ( Margarops fuscatus ) also destroys eggs and kills the young, but mainly to use the breeding caves used by Puerto Rico Amazons themselves. Like all parrot species, the Puerto Rican Amazon is colonized by various endo- and ectoparasites. Studies have shown that the nestlings are parasitized by the warble fly Philornis pici, among other things . The fly lays its eggs under the skin of newly hatched young birds. The fly larvae then develop under the skin of the growing nestlings. In the event of a strong infestation by these parasites, the young birds can die.
Existence and endangerment
Early settlers on Puerto Rico such as the Taino hunted this parrot species because they valued it as food. The dramatic population reduction is mainly due to the destruction of habitat after settlement by Europeans. The capture of young birds for the keeping of ornamental birds as well as more hunting after European settlers settled in Puerto Rico also contributed. Introduced species also contributed to the decline in the population of these parrot species. The breeding caves necessary for reproductive success are also used by the introduced honeybees. Rats and mongooses not only eat the eggs and young, but are also competing species with regard to the breeding caves.
The population is now so low that natural disasters can lead to such a massive population collapse that the population can no longer recover. Hurricane Hugo , which swept across the northeast of the island in September 1989, made this clear not only in the Puerto Rican Amazon but also in the population of the Puerto Rican wood warbler, which only occurs in Puerto Rico . As a result, no more specimens of this wood warbler were found in two of the originally four small distribution areas. The hurricane killed 24 of the still-free Puerto Rico Amazons.
The Puerto Rican Amazon is one of the 10 most critically endangered species of birds. The species has been listed on the United States Endangered Species since March 11, 1967. Efforts have been made since 1968 to increase the number of individuals living in freedom. In 1972 the United States Fish and Wildlife Service began breeding the amazon in captivity near the Luquillo State Forest. In contrast to the Kakapo , another New Zealand parrot species that is very much threatened with extinction, the Puerto Rican Amazon succeeds in doing this with great success. In 2006 the USFWS reported 39 young hatched in captivity. With only 44 individuals left in the wild, this is a remarkable achievement.
swell
Individual evidence
- ↑ Technical / Agency Draft Revised Recovery Plan for the Puerto Rican Parrot ( Amazona vittata ) (PDF; 3.7 MB) US Fish and Wildlife Service. April 1999. Retrieved June 7, 2006.
- ↑ "Although other raptors,: such as the Broad-winged Hawk (Buteo plateryptus) and the migratory Peregrine Falcon (Falco peregrinus), may be a potential threat to the parrot, there are no Documented reports of predation in the Caribbean National Forest (Snyder et al., 1987, T. White, USFWS, Rio Grande Field Office, pers. com.). Red-tailed Hawks are one the most studied raptors in Puerto Rico, and some include the karst region (Rivera-Milán 1995, Santana and Temple 1988, Snyder et al., 1987, Nimitz 2005). "( PDF )
- ^ Dieter Hoppe , Peter Welcke: Langflügelpapageien , Ulmer Verlag, Stuttgart 2006, ISBN 3-8001-4786-6 , p. 29
literature
- Werner Lantermann: parrot science. Biology, behavior, attitude; Species selection of parakeets and parrots. Parey, Berlin 1999, ISBN 3-8263-3174-5 .
- Thomas Arndt, Matthias Reinschmidt : Amazonen, Arndt-Verlag, Bretten, 2006, ISBN 3-9808245-5-1 .
- Tony Silva: A Monograph of Endangered Parrots. Mattacchione and Co, Pickering, 1989, ISBN 0-9692640-4-6 .
- Werner Lantermann: Parrots: Critically Endangered. Rasch and Röhring, Hamburg, 1990, ISBN 3-89136-386-9 .
- John Stoodley, Pat Stoodley: Genus Amazona. Bezels Publications, Lovedean 1990, ISBN 0-947756-02-7 .
Web links
- Amazona vittata inthe IUCN 2013 Red List of Threatened Species . Listed by: BirdLife International, 2012. Retrieved September 26, 2013.