The Puerto Rican Sharp-Shinned Hawk| By Gina Harris

    Photo by: Brian Sullivan

The Endangered Puerto Rican Sharp-Shinned Hawk

By Gina Harris

Historically known as "vicious small bird killers" these hawks, native to Puerto Rico, were declared as Endangered by the U.S. Fish and Wildlife Service on September 9th, 1994. At the time of the proposed status, there were only approximately 155 hawks left on the island. Now, with a Recovery Plan in action, data and research is being conducted to conclude if these measures have helped re-stabilize the population.

Source:animalia-life.club

Description of the Sharp-Shinned Hawk

These hawks are very small, ranging from 28 to 33 centimeters tall. Full grown hawks have dark gray upper bodies with heavily barred underparts. Their young are brown and heavily streaked, showing some similarities. The Puerto Rican Sharp-Shinned Hawk has a short, square shaped tail with rounded wings.

Diet

Sharp-Shinned hawks eat small birds, from woodpeckers, sparrows and shorebirds to the occasional falcon, insect or rodent.

Puerto Rican Shorebird

Puerto Rican Sparrow

     

Locations Found

The Puerto Rican Sharp-Shinned Hawk is a subspecies of the Sharp-Shinned Hawk, which are found in North America, particularly in the east U.S., Canada, and then migrate to Mexico during the winter months. Puerto Rican Sharp-Shinned Hawks are endemic to the island of Puerto Rico. Concentrations of the remaining population are limited to 5 government-owned regional forests in the north-central and eastern parts of the island. These regional forests are the Maricao Commonwealth Forest, the Toro Negro Commonwealth Forest, the Guilarte Commonwealth Forest, the Canto Commonwealth Forest and the Caribbean National Forest.

Source: ecos.fws.gov

Habitat, Breeding and Nesting Characteristics

Source: animalspot.net

Sharped-Shinned Haws are found in dense forest types, favoring closed canopy trees. These are  found in montane, elfin woodland, and rain forests. They place their nests below the canopy but above cover, close to the trunk of trees. Breeding periods take place for December to May, starting with courtship in December. In January, both the males and females construct nests, and in the months March through April, females laid their eggs and incubated them while the males found food and incubated the females.

The History of the Puerto Rican Sharp-Shinned Hawk

These hawks were discovered in 1912 in the Maricao Commonwealth Forest by researchers. They were known to the public as pests for they fed on the beloved songbirds and sometimes hunted birds who used bird feeders in people's homes.

Suspicions of Endangerment Arise

On November 24, 1980 Dr. Warren B. King from the International Council for Bird Preservation submitted a petition to be added to the Endangered Species Act. The petition, noticed by the US Fish and Wildlife Service May 12, 1981 estimated that there were only 100-200 species left on the island due to many dangerous factors. This petition concluded that more data was needed to make an informed conclusion. By December 30, 1982 the Puerto Rican Sharp Shinned Hawk was included in the Review for Vertebrate Wildlife- Threatened or Endangered List. This species was entered as Category 2 which concludes that a species may be endangered but more biological research and field studies are needed to conclude this.

Suspicions Deemed Unnecessary

On April 12, 1990, the US Fish and Wildlife service published an Annual Description of Progress and  concluded that on January 6th, 1989, the Puerto Rican Sharp-Shinned Hawk's status was changed to Category 3C. This category means that the taxa has proven more abundant and widespread than previously believed and not subject to identifiable threats. Further research or changes in land use would be needed to change this classification.

Proposed Endangered Status

On January 3, 1994 the Puerto Rican Sharp-Shinned Hawk was classified as Endangered by the US Fish and Wildlife Service. The federal documents stated that studies in 1991 and 1992 reported that populations had quickly declined and were threatened by numerous factors. There were approximately 155 birds left on the island. 

Threats to the Puerto Rican Sharp-Shinned Hawk

Habitat Destruction

There are many factors as to why the hawk population had diminished in Puerto Rico:

1. Habitat Destruction: Forests have been reduced for intensive agricultural practices. There was a 93% population decline in the Caribbean National Forest where timber practices have been most prevalent. Forests have also been cleared for leisure use such as camping. Sites have been reported as close as 100 ft. from nesting sites, disturbing the hawks, especially in nesting season.
2. Habitat Fragmentation: Roads for access to agricultural areas or camp sites have interrupted the hawks' home habitats. The construction of the PR Energy Power Authority cleared 2.6 hectares for room and continues to disturb the hawks.
3. Disease: 69.2% nest failures in the post-hatching stage are due to the warble fly, a parasite that lays microscopic larvae on hosts.
4. Loss of Genetic Variation: Because of such low populations, the current populations are susceptible to the same diseases.
5. Lack of Existing Regulations: There was a lack of comprehensive management plans for commonwealth forests.
6. Other Natural and Manmade Factors: 40% of the decline of the hawks from to 1987 to 1994 are due to illegal shooting. Hurricanes such as Hurricane Hugo of 1989 destroy whole habitats. Hurricane Maria of 2017 is estimated to have many setbacks in conservation practices that are currently in progress.

   

   Source: pubs.usgs.gov
   

   
   

A Recovery Plan In Action

A recovery plan was established on September 9, 1997 with a goal of restoring the population of the Puerto Rican Sharp-Shinned Hawk with at least 250 pairs island-wide and should be maintainable for at least 7 years. A five-year review published in 2007 showed that the hawks were still endangered.

Estimated Date of Recovery: Down-listing of species by 2025.

Estimated Cost: $675,000 in the first 3 years.

Outline:

• Monitor-

• Conduct surveys within range to determine populations and trends.
• Identify additional habitat for species.
• Determine spacial and temporal usage of habitat.
• Obtain population biology information from researchers.
• Identify imminent mortality factors and threats.
• Evaluate possible adverse impacts.
• Protect and Manage Population and Habitats-

• Develop and implement management plans
• Enforce existing commonwealth and federal endangered species regulations.
• Obtain protective status for habitat on privately-owned lands.
• Restrict public activities to at least 500 meters away from known nesting sites.
• Make timber demonstrations and silviculture practices designed to withstand the hawks' favorable conditions.
• Restrict access to forests during breeding seasons between December-June.
• Develop Public Education Programs
• Refine Recovery Goals
• Determine number of population necessary to ensure stability, security and self-perpectuation.
• Determine if there are any other additional factors needed to be prevented.

What Can You Do?

Stay informed about the Puerto Rican Sharp-Shinned Hawk by checking in with the US Fish and Wildlife profile for the Puerto Rican Sharp-Shinned Hawk here.

If you live in Puerto Rico, do not engage in any illegal activities such as shooting the hawks, trespassing into restricted areas, or camping in undesignated areas. Educate yourself and others about the affects you have on the populations and wellbeing of these hawks if you do engage in these activities.

If you would like to volunteer, you can use the filter search page on the US Fish and Wildlife page to find any positions. You can use this search engine to volunteer for any species of your choosing!

Use the following websites of organizations devoted to participating in the recovery plan to find more volunteering and donation opportunities:

• Puerto Rico Department of Natural and Environmental Resources
• The Peregrine Fund

• To donate
• To volunteer
• The U.S Forest Service
• To volunteer
• To donate
• International Council for Bird Preservation
• To support

Citations

“Birds of Puerto Rico.” Puerto Rico Wildlife, alfredocolon.zenfolio.com/f99233350.

Cain, A.J. “Taxonomy.” Encyclopædia Britannica, Encyclopædia Britannica, inc., 31 Oct. 2017, www.britannica.com/science/taxonomy/Nomenclature#ref498177.

Carrington, Sean. Montane communities, ecflora.cavehill.uwi.edu/bio_courses/ECOL2453/ecol2453_sc/Montane_communities.html.

“Montane forests.” WWF, wwf.panda.org/what_we_do/where_we_work/borneo_forests/about_borneo_forests/ecosystems/montane_forests/.

Service, U.S. Fish and Wildlife. Species Profile for Puerto Rican Sharp-Shinned hawk (Accipiter striatus venator), ecos.fws.gov/ecp0/profile/speciesProfile?sId=604.

“Sharp-Shinned Hawk Life History, All About Birds, Cornell Lab of Ornithology.” , All About Birds, Cornell Lab of Ornithology, www.allaboutbirds.org/guide/Sharp-shinned_Hawk/lifehistory.

“Sharp Shinned Hawk.” Animal Spot, www.animalspot.net/sharp-shinned-hawk.html.