The Puerto Rican Amazon reaches sexual maturity between three and four years of age. It reproduces once a year and is a cavity nester. Once the female lays eggs she will remain in the nest and continuously incubate them until hatching. The chicks are fed by both parents and will fledge 60 to 65 days after hatching. This parrot's diet is varied and consists of flowers, fruits, leaves, bark and nectar obtained from the forest canopy.
Description
The Puerto Rican Amazon measures 28–30 cm (11–12 in) and weighs 250–300 g (8.8–11 oz), or 275 g (9.7 oz) on average. Although small compared to Amazons in general, it is similar in size to other Greater Antilles Amazona species. Sexual dimorphism is not present. Both males and females have predominantly green plumage, though their feathers have blue edges. The primary flight feathers of the wings and the main covert feathers are dark blue. The color of the feathers on the underside varies depending on the body part: the feathers on the underside of the wings, which can be seen during flight, are bright blue; those in the tail have yellow-green tone. Their underparts are paler and yellow-tinged, their foreheads are red, and they have white ovals around the eyes. The iris is brown, the bill a horn color, and the legs yellow-tan. Aside from DNA tests, males and females can only be distinguished by behavioral differences during the breeding season. Immature birds have plumage similar to adults.
Behavior
The Puerto Rican Amazon is diurnal, typically beginning its day half an hour after sunrise. It is generally secretive when inside its nest, using its green plumage as camouflage. In contrast, it may be vocal and noisy when outside the nest. Upon taking flight, its color pattern provides some contrast to the forest. The flight mechanism of this species is similar the one found in other Amazons, and involves strokes below the body axis, unlike most birds whose wings flow above their bodies in flight. Amazons can fly moderately fast, reaching a top speed of approximately 30 km/h (18 mph), and are fairly agile when evading predators in mid-air. When in search of food, the parrots group in pairs. Couples and their fledged young display a tendency to stay together. The Amazon makes two flight calls, a take-off squawk which consist of a pattern of long squawks, and a loud "bugle", commonly used in flight and which may have several meanings depending on the circumstances when it is used.
Breeding
The Puerto Rican Amazon usually mates for life, with pairs only changing mates if one bird perishes or abandons the nest. A male may abandon the female if the latter is injured, re-mating with a more "physically perfect" subject. The pairing process is unknown; however, new pairs tend to participate in mutual mating dances characterised by coordinated bows, partial extension of the wings and full tail expansion.
The Puerto Rican Amazon is a secondary cavity nester, nesting in tree trunk cavities, both naturally occurring and excavated by other species. It prefers to nest in Palo colorado trees (Cyrilla racemiflora), but uses other trees, including the laurel sabino (Magnolia splendens) and tabonuco (Dacryodes excelsa), to a lesser extent. These trees are mature cavity-forming trees which provide protection against predators and the entry of water. Recently, the species has also nested in artificial wooden boxes designed as part of the recovery plan for the species. Nest height varies from 7–15 m (23–50 ft) above ground. The male usually leads the search for nest sites, although the final decision seems to be taken by the female. Once a site is selected, the pair will spend some time inspecting and cleaning it. No lining material is added to the nest.
The Puerto Rican Amazon reaches sexual maturity at 4 years of age in the wild and at 3 years in captivity. The species usually reproduces once a year between the months of January and July (the dry season). Copulation between pairs seems to be closely related to food transfers, with this possibly serving as a trigger for intercourse. Amazons have a copulation pattern similar to that found in other parrots throughout the Americas, with the male gripping a perch with one leg while passively placing the other in the female's back. As the time for egg-laying approaches the pair spends more time in the nest, with the male providing food to the female via regurgitation. The female lays 2–4 eggs that she exclusively incubates for a period of 24 to 28 days, while the male will be present in the vicinity of the nest when providing food. Females rarely leave the nest, leaving it on rare occasions involving repelling predators or if the male has not brought food in an extended time frame. The chicks are fed by both parents until they leave the nest, usually 60 to 65 days after they hatch. Nonetheless, they remain dependent on their parents and travel with them until the next breeding season.
Like other Amazons, the Puerto Rican Amazon is gregarious while performing daily activities, but territorial around its nest. The size of the territory around the nest is usually around 50 meters (164 feet). Pairs are extremely cautious near their nest, usually moving in a slow manner when leaving the nest to avoid the attention of predators. Although territorial defense is mostly composed of loud vocalizations there are instances of actual physical combat. Pairs will defend their nest sites against invading couples, sometimes focusing on the location's defense instead of egg-laying. Pairs nesting in areas uninhabited by other parrots will remain mostly silent unless other parrots enter the zone. Some pairs may display moderate territoriality even when not apparently intending to nest, with these tendencies beginning in the latter half of the breeding season. One hypothesis is that this would occur in young pairs that had still not reached full maturity, serving as "practice territoriality".
Threats and conservation
On March 11, 1967 the Puerto Rican Amazon entered the United States Fish and Wildlife Service list of endangered species list. At the time of inclusion the population was estimated at 70 individuals. In 1968, recovery efforts began to increase the population in the wild. In 1972, when the estimated population was 16 individuals, the United States Fish and Wildlife Service (USFWS) at the Luquillo Aviary began efforts to breed parrots in captivity and yielded good results. In June 2006, it was reported by the USFWS that its birds in captivity had successfully hatched 39 chicks (the yearly average is around 16). In 2006, 22 birds were released in the Rio Abajo State Forest to initiate a second wild population, and a further 19 were released at the same site on 27 December 2008.
The World Conservation Union (IUCN) lists the Puerto Rican Amazon as a critically endangered species since 1994. The species is regulated under Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), rendering illegal international trade in specimens or parts.
