Even before Hurricanes Irma and Maria, the entire recorded population of Puerto Rican Sharp-shinned Hawks was just 75 individuals in the 2017 breeding season. We feared the worst after the hurricanes in September, wondering if any bird could survive sustained winds of 155 mph.
Sifting through the remains of the flattened forest in January, we found a small miracle: at least 19 Sharp-shinned Hawks survived. With few nest trees remaining and very little prey, we’ve mounted a rescue mission… to change the future.
Puerto Rican Sharp-shinned Hawks were added to the U.S. Endangered Species List in 1994. We have surveyed the population annually since 2015 and observed 75 individuals in four locations, all in forests above 750 meters elevation.
A baseline study from 1978–1985 estimated a total population of 240 individuals spread across five locations.
Although the hawks’ situation is dire, it’s not the worst we’ve seen; we helped recover the Mauritius Kestrel, another island endemic, from just four individuals in the 1980s. Captive breeding, releases, and nest box management with local partners have increased the population to more than 800.
Puerto Rican Sharp-shinned Hawks don’t migrate, nor are they found anywhere beyond their island stronghold, in habitat depleted by human land use. The hawks depend entirely on the dense mountain forests of this Caribbean island for nesting and hunting. Like Sharp-shinned Hawks on the American mainland, they are agile fliers, but they’re smaller and have brighter plumage.
Of the 19 hardy survivors, nearly all are paired; but despite being well into the 2018 breeding season, few were building nests or showing signs of egg-laying. Their chance of success is extremely low. Hurricane Maria decimated the forests, actually stripping the leaves off the relatively few trees left standing. The majority of mature trees were blown down, uprooted, or snapped off, leaving only palm trees and tree ferns. Without foliage, any nestlings that might hatch won’t be sheltered from heat, rain, or predators.
Even adult birds are subject to starvation because their main prey—small birds like tanagers, warblers, and vireos—also depend on adequate forest habitat. In such difficult conditions, it’s likely that few of the remaining Sharp-shinned Hawks are healthy enough to breed successfully.
Our first step was to provide supplemental food to prevent starvation and enable the surviving hawks to lay eggs. As eggs have appeared, we’ve carefully moved some of them into incubators to hatch in a secure, climate-controlled conservation breeding facility on the island. Since these hawks normally produce a second set of eggs if the first set is lost, we’ll be able to raise chicks in the safety of our facility without compromising the wild parents’ success. The young we raise will be released to boost the population until nearby forests are restored by local partners. Given the scale of devastation in Puerto Rico’s forests, we estimate a full recovery could take up to 20 years.
Few organizations have the expertise or resources to respond to an emergency of this scope, but The Peregrine Fund has returned numerous raptor species from the brink. We expect to learn a great deal in Puerto Rico. This rescue operation will hone our skills for a future of extreme weather and ever more threatened island species.