Puerto Rican Amazon - Population and Distribution

Population and Distribution

The precise distribution of the Puerto Rican Amazon before the arrival of Spanish colonialists is uncertain, because of a lack of contemporary records and then the extermination of the indigenous Taíno people, but the species was apparently widespread and abundant. There is also evidence the species may have inhabited other nearby islands, such as Antigua, Barbuda and the Virgin Islands. Estimates of the parrot's early numbers vary greatly. Some authorities claim that there were once more than a million individuals, while others suggest a more modest population of 100,000. During the first 150 years of Spanish rule the human population was small, and in 1650, when the population of the island was 880 people, the species was still abundant throughout the archipelago. After 1650, human habitation increased exponentially, and by the 18th century the Puerto Rican Amazon population started to be affected. Heinrich Moritz Gaede, a German naturalist, declared that by 1836 the parrot population had noticeably declined. Even so, as late as 1864, British ornithologist Edward Cavendish Taylor noted that the parrots were still common near the island's capital, San Juan.

At first, human activity had not posed a significant threat to the Puerto Rican Amazon. The Taíno hunted the parrot but without much effect on its population. In the past two hundred years, however, many factors have led to a drastic decrease in the birds' numbers: agricultural development, the construction of roads, hydroelectric development, and the adoption of young chicks as pets. Especially during the latter half of the 19th century, most of Puerto Rico's virgin forests, a historical habitat of the species, were cleared for agricultural development, primarily for the production of sugar, cotton, corn and rice. The Amazon quickly came to rely on these crops as its main food source and so became seen as a pest; local farmers repelled or hunted the bird if possible. As agriculture expanded, the Amazon's habitat disappeared further and its population declined.

The species was historically found in mature or old-growth forests in Puerto Rico at all elevations, and in holes, cliffs, and other diverse habitats at lower elevations. The species could be found at medium elevations in the Guajataca State Forest (until 1910) and the Rio Abajo State Forest (until the 1920s), and at high elevations in the Carite State Forest (until the 1930s). Accounts from the early 1900s describe the parrots traveling away from the Luquillo forest and the Sierra de Cayey towards the main island's coast to find food. At the same time, the species was extirpated from Puerto Rico's smaller islands—Culebra, Vieques and Mona—and became restricted to five locations: two in karst-limestone areas, two in high montane rainforests and one in mangrove forest at the foot of the El Yunque National Forest. One of these karst regions, located in the northwestern part of Puerto Rico, was identified as a haven for the species. In particular, a region named Valle de las Cotorras (Valley of the Parrots), located between San Sebastián and Morovis, was home to a sizable population. Some Amazons survived in small pockets of degraded forest but these proved insufficient to support large colonies. Eventually their natural habitat was reduced to the Cordillera Central and undisturbed forest areas, and by 1940 they were only to be found in primary forest at the Luquillo Mountains in El Yunque National Forest. The species is currently found at elevations between 396 and 823 m (1,299 and 2,700 ft). Since the species requires mature forests with open-cavity trees for reproduction, it does not occur in dwarf and secondary forests.

By the 1950s, there were only 200 parrots in the wild, and in 1975 the population reached an absolute low of 13 individuals. Numbers then recovered, and in August 1989 there were an estimated minimum of 47 individuals. But on September 18, 1989, Hurricane Hugo struck the northeast coast of Puerto Rico inflicting heavy casualties on the remaining birds. In the aftermath of the hurricane the population was estimated at 23 individuals. In 2004, the wild population was 30–35 individuals, and the long-term trend appears to be stable albeit with some fluctuations. The current range of the species is 16 km2 (6.2 sq mi), 0.2% of what it once was.