The harpy eagle or greater harpy (Harpia harpyja) is an eagle of the Accipitridae family of the Accipitriformes order. It is the largest bird of prey in the Western Hemisphere and in all of South America.
Harpy eagles are considered the most powerful in the world, occupying the top of the trophic chains, especially in the canopy of the forests where they live. The harpy eagle is an uncommon species in much of its range because it requires very special conditions.
Harpy Eagle (Harpia harpyja) By Brian Gratwicke from DC, USA
Like other large raptor species, they need vast wooded areas to be able to cover their food needs and special requirements for their reproduction. Estimates indicate that a population of 250 pairs of harpy eagles needs at least 37,500 km².
The selective logging of tree species in which these birds usually nest poses a great threat to the occurrence of reproductive events and nesting. They have very low reproductive rates as they raise a single harrier every two to three years.
The low connectivity between intervened forest systems can greatly affect gene flow between populations.
These raptors are considered the strongest and one of the most robust in the world. The body size of females is considerably larger than that of larger eagles. The harpy eagle, due to morphological adaptations to its habitat, developed a smaller wingspan to move agilely in the forest canopy.
These raptors consume more than 70 species of vertebrates including mammals of various sizes, birds, and arboreal reptiles. Their most frequent prey are by far the sloths, Bradypus variegatus and Coelopus didactylus, representing between 80 and 90% of their diet, both in terms of captured individuals and biomass.
Females can carry prey up to twice their weight, about 18 kg. So far, research on the success of capture in their hunting activities is scarce.
General characteristics
They are large eagles, as the females can reach a height of 1.1 meters. Their wingspan is relatively small compared to other raptors, however, they exceed two meters in length.
Males are less robust than females, weighing between 4 and 5 kilograms while females weigh between 6 and 9 kilograms.
The adults have a leaden gray color on the head, with a forked crest of blackish coloration characteristic of the species.
The wings and the dorsal region are black, the lower back region and the supracaudal coverts have white spots. The tail is elongated and wide, with four black and three grayish stripes separating them.
The chest is black, the thighs have black horizontal stripes, the rest of the ventral region is white. The beak is black and the tip is hooked. The tarsi are bare and yellow along with the legs. The legs are strong and have large claws up to 10 cm long.
Juveniles have a white neck, head and belly, and cream-gray back and wings with black splashes. There are at least four color changes in the subadult stage.
Habitat and distribution
This species occupies a great diversity of lowland tropical and subtropical humid forests. They are found in tall evergreen forests, sub-evergreen forests, deciduous forests, thorn forests, and mountain mesophilic forests.
Its typical elevation range is below 900 meters elevation. However, there are records close to 2000 meters.
These eagles use the emerging trees of the forest to establish their nests, that is, those trees that exceed the canopy. Also the forest canopy area is their favorite area for hunting and flying.
These birds can be slightly tolerant to habitat intervention, being able to establish themselves in fragmented forests and wooded patches surrounded by grassland matrices, agricultural, livestock and forestry borders. Several nests have been recorded within a few kilometers of small towns.
Its original distribution ranges from southern Mexico, through Central America (Belize, Honduras, Nicaragua, Costa Rica, Panama) and in South America (Colombia, Venezuela, Guyana, French Guiana, Suriname, Brazil, Ecuador, Peru, Bolivia, Paraguay, to Northeast Argentina).
From Mexico to Panama, their abundance is discontinuous and they are considered rare. Already in Panama and several countries in South America, its distribution becomes more homogeneous.
Taxonomy
The genus Harpia contains a single species, Harpia harpyja. At present, there are no known geographic variants of harpy eagles even though they are widely distributed.
Together with species of the genera Morphnus and Harpyopsis, they form a group of related raptors, conforming to the Harpinae subfamily within Accipitridae.
The harpy eagle can often be confused with Morphnus guianensis, also known as the silver eagle. The latter is a very similar species and can be found in many of the areas where the harpy eagle is distributed.
They can easily capture a wide variety of primates such as the howler monkey Alouatta seniculus, and smaller ones such as Saguinus graellsi, Saimiri sciureus, Cebus spp, Pithecia monachus, Callicebus spp. and Lagothrix lagotricha.
Other arboreal mammals on which they feed are Potos flavus, various species of porcupines of the genus Coendou, and marsupials such as Didelphis marsupialis.
They also successfully hunt top predators such as Leopardus pardalis, Eira barbara, Nasua nasua, and land mammals such as the rodent Dasyprocta fuliginosa and the armadillo Dasypus novemcinctus.
Among the birds, they capture macaws like Ara ararauna and galliform birds like Pipile pipile.
The diet varies in composition depending on the areas in which they are nesting and the spatial distribution of the prey. Juveniles often chase groups of wild guan like Ortalis ruficauda.
Behavior
Harpy in captivity By Nori Almeida
Juvenile and sub-adult specimens are usually quite curious. They do not show any degree of fear in the presence of man, being an easy target for their hunters.
These animals choose to perch the highest branches of the canopy, in this way they study their territory. They tend to choose habitats with water availability, which translates into constant prey availability during drought.
When threatened they usually flatten the feathers of the crest on the neck. The females defend the nest from possible predators of the harriers, as well as parasitic or opportunistic animals from the prey that is provided to the chick.
These birds hunt more frequently when the sun is high, so that their prey is taken by surprise. In this way, it very stealthily attacks groups of social mammals such as primates.
The young spend much of their youth, after leaving the nest, within the territory of their parents. Due to the territoriality of these eagles, the survival of the juveniles can be improved. As the calf matures into a developed adult, it moves further and further away from the birthplace to establish its own territory.
References
- Aguiar-Silva, FH, Sanaiotti, TM, & Luz, BB (2014). Food habits of the Harpy Eagle, a top predator from the Amazonian rainforest canopy. Journal of Raptor Research, 48 (1), 24-36.
- BirdLife International 2017. Harpia harpyja (amended version of 2017 assessment). The IUCN Red List of Threatened Species 2017: e.T22695998A117357127. http://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T22695998A117357127.en. Downloaded on 04 November 2019.
- Chebez, JC, Croome, MS, Serret, A., & Taborda, A. (1990). The nesting of the Harpy (Harpia harpyja) in Argentina. Hornero, 13, 155-158.
- Lenz, BB and Marajó Dos Reis, A. 2011. Harpy Eagle – primate interactions in the Central Amazon. Wilson J. Ornithol., 123: 404-408.
- Muñiz-López, R. (2008). Review of the situation of the Harpy Eagle Harpia harpyja in Ecuador. Cotinga, 29, 42-47.
- Piana, Renzo. (2007). Harpia harpyja Linnaeus nesting and diet in the Native Community of Infierno, Madre de Dios, Peru. Peruvian Journal of Biology, 14 (1), 135-138.
- Rettig, NL (1978). Breeding behavior of the harpy eagle (Harpia harpyja). The Auk, 95 (4), 629-643.
- Vargas, JDJ, Whitacre, D., Mosquera, R., Albuquerque, J., Piana, R., Thiollay, JM, & Matola, S. (2006). Current status and distribution of the harpy eagle (Harpia harpyja) in Central and South America. Neotropical Ornithology, 17, 39-55.
- Vargas González, JDJ & Vargas, FH (2011). Nesting density of Harpy Eagles in Darien with population size estimates for Panama. Journal of Raptor Research, 45 (3), 199-211.