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The Peregrine Fund Notes From The Field
Experiences with the Reintroduction of a Captive-bred Harpy Eagle into a wild Ecosystem in Darien, Panama.
José de Jesús Vargas González — in Harpy Eagle Conservation and Research    ShareTwo seasons have gone by in the Neotropical forest of Darien since the release of the Harpy Eagle called KC, well-known in the local community as Nepono, which means “flower” in the Embera language. KC was released into the Forest Reserve of Chepigana with several goals in mind - all of which are aimed at developing guidelines for a successful reintroduction of captive-bred Harpy Eagles in natural environments where wild Harpy Eagles already live. We decided to release KC in the forest surrounding the community of La Marea, for several reasons. But, the main idea was to influence a courtship between our captive-bred bird and a resident wild male Harpy Eagle that recently lost his mate.

KC with a sloth
KC with a sloth
KC hatched on December 31, 2004, at The Peregrine Fund’s Neotropical Raptor Center in Panama. More than a year after hatching, she was released in Soberania National Park, in the Panama Canal Area, where she successfully adapted to her environment. In January of 2009, we trapped KC and temporarily held her in quarantine to make sure she was healthy before we re-released her into the forests of the Darien Province of Panama. On February 21, KC was transported to the study region, and released a month later, after having had vocal interactions with the wild male Harpy Eagle.

In order to collect data after KC was released, we established a monitoring plan. Each day, we followed KC for at least five hours to document any interactions with the wild male Harpy Eagle or other individuals. We collected bioecological data, which is important for making better management decisions aimed at conserving this threatened species and its habitat.

Our intention to bring KC and the wild male together was not successful. Many hypotheses can explain or justify why these two birds did not mate. Perhaps it was KC’s age and/or the possible natural incompatibility between them. However, only these birds know the exact reasons. Nevertheless, we learned a lot from this unsuccessful part of the experiment. We documented intra-specific interactions with wild Harpy Eagles and collected data to gain a better understanding of the tolerance level and adaptability of this species in different types of ecosystems. Today, our preliminary data suggest that: 1. KC is not a resource competitor for other adult and juvenile Harpy Eagles; 2. KC has adapted successfully to a natural environment; 3. KC had positive interactions with other individuals of her species; 4. KC can use different types of forests, with homogeneous and heterogeneous ecosystems, including areas with human intervention; and 5. KC is an excellent icon to raise awareness in local communities about the conservation of this species.

Tracking KC
Tracking KC
During this past year of constant monitoring effort, KC travelled around 130 km from the release site in La Marea. Most recently, she has been located in the Serrania del Sapo, an amazing contiguous forest near Puerto Piña. We have documented three different interactions between KC and three adults males and one juvenile female Harpy Eagle (see map), as well her visits into active breeding territories of other Harpy Eagles. Any aggressive interactions were documented. It is incredible how much we have learned and continue to learn from this research experience with KC. The interactions we witnessed were both visual and vocal, and suggest that these interactions lasted for hours, without any intimidation or aggressive behaviour. In fact, on several occasions, KC was seen with a different wild male. At times, they were observed perching close together - at distances of under 5 meters in the same tree. They sometimes vocalized back and forth and even flew together. For this reason we considered these interactions as positive, which led us to conclude that captive bred Harpy eagles can live with wild Harpy Eagles, and disperse in case the territory is occupied, without any aggressive behaviour.


Before the release of KC in Darien, we had several concerns, mainly regarding the survivorship of KC in an environment where we knew wild Harpy Eagles were present. Today we can support the claim of “survival of the fittest”, as KC has shown to be a very fit individual. The survival of this eagle is clear proof of the great value of all the rearing, development and reintroduction efforts made by our team at The Peregrine Fund.

KC with a crab-eating raccoon
KC with a crab-eating raccoon
In the very diverse and amazing ecosystems of the Darien forest, KC has captured a great variety of prey, such as sloths, primates, and carnivores among others. KC has been an outstanding predator of the forest basin, standing on the top of the trophic chain. We have documented how KC searches for, chooses and captures her prey, always following a cost-benefit rule. On some occasions KC watched her prey for several hours, but did not proceed to hunt it, despite it seeming, at least to us, an easy catch. We have developed several hypotheses as to why this happened including: perhaps the site was not the best for making the capture, or there was some risk of KC getting hurt. Several other hypotheses have been considered, all of which enrich our study and feed our desire to learn more.

We monitored KC’s movements through mature forests with open understory vegetation as well as through complex habitats where the dense vegetation made it very difficult to move. This Harpy Eagle has utilized mainly mature forests with large homogeneous extensions. But we have also followed her into mangrove forests, cativales, and secondary forests as well as agricultural fields. This diversity of habitat suggests this species’ great adaptability, as long as it is not killed by humans.

What motivates KC to move great distances? We can speculate and say that it is because she is a young eagle, wandering, and flying without direction. Or it may just be due to disorientation from being in a completely new environment. Perhaps she is looking for an ideal area that meets her requirements, or maybe it is because she found other eagles in the surroundings and prefers an empty territory. Perhaps it is because she is young and is searching for a mate, and later a territory and a good place to build her nest. There are many questions that arise from KC’s movement patterns. Day by day we collect more data and we are better equipped to study her habitat requirements and closer to understanding her behaviour.

Anthropogenic barriers, such as deforested areas, may force KC to deviate from her path, and occasionally use forest remnants to surpass poor habitats and reach better areas. Each inference that we make from observations of KC creates new concerns regarding the requirements for healthy populations of Harpy Eagles, especially in contrast to the growing trend in soil use and deforestation.

Today, in the study area our work team is known as the “Harpy Eagles”. Both children and adults call us eagles and ask us about Nepono, who has become a popular individual, especially among children. This is the result of the radio advertising that we constantly play so that all the community learns about Harpy Eagles, especially about Nepono.

KC in a tree
KC in a tree
KC visited some indigenous and farmers’ lands, as part of her exploratory travels, and thanks to our communication efforts she has not fallen victim to hunters. Whenever we have the opportunity, we talk informally with local people to teach them about our project and the presence of KC. This way we avoid that our Nepono will be hurt due to ignorance.

A lot more work is necessary to accomplish our research with KC, but we have the energy and enthusiasm to continue following our wild flower “Nepono.”

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