- Order: Accipitriformes
- Family: Accipitridae
- Polytypic 2 Subspecies
Brown and Amadon (1968) considered medium-sized to large-sized birds to be the primary prey, but noted that mammals as large as kinkajou (Potus flavus) also are included in the diet. However, two studies of prey items have shown mammals to comprise slightly less than half of prey brought to nests. Flatten et al. (1989) studied 52 prey items in Tikal National Park, Guatemala, and identified 40.4% as avian, 46.1% as mammalian, and 13.5% as unidentifiable. In Manaus, Brazil, Klein et al. (1988) found 63.5% of 49 identified prey items to be avian, 32.7% to be mammalian, and 4.1% to be reptiles; these included tinamous (Tinamus sp. and Crypturellus sp.), macaws (Ara sp.), toucans (Ramphastos vitellinus), guans (Penelope sp.), and chachalacas (Ortalis motmot), and mammals including opossums (Didelphis sp. and Matacharis sp.), agouchi (Myoprocta sp.), and porcupines (Coendu sp.). They also report squirrel monkeys (Saimiri sciureus), tamarins (Saguinus fuscicollis), spiny woodrats (Proechimys sp.), and Purple Gallinules (Porphyrula martinica) taken at Manu, Peru. Lyon and Kilham (1985) observed prey deliveries involving a young tinamou (Tinamidae), Plain Chachalaca (Ortalis vetula), a young Crested Guan (Penelope purpurascens), Gray-headed Dove (Leptotila plumbeiceps) and a leaf-nosed bat (Phyllostomatidae), as well as an unidentified white bird. In Trinidad and Tobago, french (1991) reported prey to be primarily birds and that it is known to have taken chickens. Others have reported the following prey: Great Currasow (Crax rubra; Russell 1964), vultures (Cathartidae; Stiles and Skutch 1989), Guianan Cock-of-the Rock (Rupicola rupicola; Trail 1987), green iguana (Iguana iguana; Clinton-Eitniear et al. 1991), a lizard (Teiidae; Klein et al. 1988), and snakes (Klein et al. 1988, ffrench 1991). Acosta-Chaves et al. (2012) report an observation of a hawk-eagle capturing a Long-tailed Silky-flycatcher (Ptilogonys caudatus).
When hunting, it mostly still hunts from hidden perches and swoops in to pounce on prey or give a swift tail chase (Ferguson-Lee and Christie 2001, Ridgely and Gwynne 1989). Occasionally power dives at high speed into colonies of herons or troops of monkeys (Hilty 2003). Several attacks have been observed. At a Guianan Cock-of-the-Rock lek, Trail (1987) observed single Ornate Hawk-Eagle attacks on eight of 254 days; two attacks resulted in successful kills, and in this study these were the only successful kills out of 56 attacks by six species of raptor. In both successful attacks the hawk-eagles made shallow dives into the active lek and struck male cock-of-the-rocks on or near the ground and killed them instantly. In one kill, the hawk-eagle plucked its prey on a fallen trunk just beyond the lek, but in the other case it carried the prey away from the lek. Kilham (1978) described an attack on a Crested Guan, wherein the hawk-eagle swooped in on four Crested Guans. The guans flew off in four different directions and the one that was pursued by the hawk-eagle began screaming loudly and giving guttural sounds and growls while perched in the middle of a tree. The hawk-eagle was apparently impeded by tangled branches and unable to reach the guan; it eventually gave up at which point the guan switched to more typical "cawk, cawk, cawk" calls. Friedmann and Smith (1955) report a successful capture of an adult guan.
Often seen perched on emergent snags or on forest edges, where it may survey the surroundings in the early morning. During the day, it is more often seen perched on large limbs within the forest. It hunts from perches in the mid to upper levels of the forest and makes swift flights between them or to attack prey.
In mid-morning, it may soar over the forest canopy calling tirelessly (Howell and Webb 1995). This species soars less frequently than its congener the Black Hawk-Eagle (Spizaetus tyrannus), usually circling fairly low whereas Black Hawk-Eagle often circles quite high above the canopy. Ridgely and Gwynne (1989) note that Ornate Hawk-Eagle frequently intersperses rapid, shallow “butterfly-like” wingbeats as it circles low over the canopy and these display flaps seem often to be performed during each bout of calling. Black Hawk-Eagle also is more vocal, although Ornate similarly delivers its whistling calls while circling over the canopy.
At a Guatemala nest, the female aggressively defended the nest against humans climbing to a blind near the nest, almost striking them; interestingly, the male did not defend the nest under similar circumstances when incubating (Lyon and Kilham 1985). In two encounters with spider monkeys (Ateles paniscus), the female vigorously defended the nest on the first encounter, swooping on them, but on the second encounter the female remained on the nest. When the egg was near hatching, the female responded to the presence of soaring raptors and vultures by raising her crest, mantling the egg, and calling loudly (more intensely depending on the proximity of the raptor). In Oaxaca, where the female had been collected before the nest was discovered, the male actively defended the nest against a climber (Lyon and Kilham 1985). In Manaus, Brazil, the female was not as strongly territorial and did not react to workers with chainsaws within 38 m of the nest or to nearby macaws; she did call when Greater Yellow-headed Vultures (Cathartes melambrotus) passed by, but otherwise did not show signs of nest defense (Klein et al. 1988).
Little information on mating system. Howell and Webb (1995) describe the flight display as a climb with deep floppy wingbeats followed by a stoop with wings closed, almost somersaulting at times. A courtship maneuver described by Slud (1964) thus: "Calling in a very excited manner, the bird falls with folded wings, then opens them up at the bottom of the dip; sometimes it completes a perfect loop." A display reported by ffrench (1991) involves the pair gliding in tight circles, the male approaching the female from above and behind, as the female rolls to her back and they engage in talon grabbing, occasionally touching.
No information on extra-pair copulations.
Social and interspecific behavior
Solitary, except when breeding; young remain dependent on the parents for many months after fledging.
Nests are typically placed at high to mid-levels (20-30 m) just below the canopy in sprawling, often emergent, trees. Nests generally are a bulky platform of sticks about 1 m wide and 50 cm deep, with green sprigs lining the basin and rim. Lyon and Kuhnigk (1985) give details on four nests. One in Guatemala was 20 m high in a 30 m silk cotton tree (Ceiba pentandra), wedged in a fork of a large side branch and 5 m out from the trunk (Lyon and Kuhnigk 1985). Another was 26 m up in a 30 m silk cotton tree and 5 m above the canopy. Both nests were oblong, made of sticks (5-10 mm in diameter), about 1 m in diameter and 0.5 m deep. A Panama nest was 28 m up in the crotch of a 31 m cativo tree (Prioria sp.) (Brown and Amadon 1968) and one in Oaxaca, Mexico, was in the crotch of the main trunk of a pine tree (Pinus sp.). A nest in Manaus was placed 37 m high in a 46 m tree (Hymenaea sp.) and measured 1.7 m in diameter (Klein et al. 1988). Nests in Trinidad (ffrench 1991) have been high in the fork of a sprawling forest tree; those in the Chan Chich area of Belize (MJI pers. obs) have also below canopy on large sprawling branches some distance from the trunk.
Observed nests (Kiff and Cunningham 1980, Lyon and Kuhnigk 1985, Klein et al. 1988) have all contained a single egg or young; other Spizaetus eagles also have a clutch size of one (Kiff and Cunningham 1980). Kiff and Cunningham (1980) described two eggs laid by a captive female. The eggs were a short oval shape, not glossy, and had a somewhat pitted surface. The weight of the two eggs was 58.520 g and 60.294 g and the dimensions 58.17 x 43.37 mm and 57.71 x 44.18 mm, respectively. The color of eggs may vary: Lyon and Kuhnigk (1985) reported a white egg with small brownish splotches, while Kiff and Cunningham (1980) reported unspotted bluish-white eggs.
Timing of nesting varies regionally. At Tikal in Guatemala, the estimated timing of nesting was egg laying in the second week of March and fledging in late June or July; the hatching here may be timed to correspond with the fledging of prey species from late April to May. In Costa Rica, a well-grown nestling was in the nest April-May (Stiles and Skutch 1989). In Trinidad, ffrench (1991) reports nest-building in November, hatching in March, and fledged young still near the nest in August. In Venezuela, nest building was reported in March (Hilty 2003). In Manaus, Brazil, eggs were laid in early August and fledging, the young hatched 17 September, and fledging occurred in mid-November.
Detailed accounts of nestings in Tikal, Guatemala (Lyon and Kuhnigk 1985) and Manaus, Brazil (Klein et al. 1988) provide the best information on nesting biology of the species. In Guatemala, the female performed 95% of the incubation during the last two weeks of incubation and over 127 hours of observation, the nest was left unattended for only 9 minutes. During incubation, the female collected leafy green springs for the nest bowl at least once a day and always before 0800. The female in Manaus similarly continued to augment the nest with fresh sticks throughout the nesting period and removed prey remains two to four times a day. While the females incubated, the males provided prey for the females, and it appears that females hunt only very rarely or not at all during this time. Prey exchanges in Brazil began with the male calling to the female, who would call back from on or near the nest. The calling bouts usually lasted 2 to 8 minutes before prey exchange occurred. The calling bouts were not described for Guatemala, but always took place several hundred meters from the nest and the male took over incubation for 0.5 h to 1 h (exceptionally 2 h) while the female fed. The visits to the nest by the male usually at least once a day and were always before 1200 (Lyon and Kuhnigk 1985), but in Brazil the male never approached the nest except once, when he was aggressively chased away by the female.
The Guatemala nest failed, but Lyon and Kuhnigk (1985) describe interesting behavior around the hatching of the chick. One day before hatching, the female began incubating with her wings out and tail spread, and she continued this behavior after the egg hatched. Just two hours prior to the egg hatching, the male brought prey to the nest for the first time. When two days old the chick could hold its head up to be fed and when two days old it could move about enough to defecate over the edge of the nest cup. On 27 April the female behaved oddly, salivating and thrashing her head about, and soon thereafter she left the chick exposed in the nest and the chick soon died. Lyon and Kuhnigk (1985) speculated that the extreme heat of the day or stinging ants may have caused the nest desertion. After the death of the chick, the adults remained in the area for two more days and continued bringing leafy sprigs to the nest bowl.
In Brazil, copulation by adults were seen in the area of the nest in June and copulation was observed on 24 June with egg laying estimated to be in early August, suggesting a long courtship period. The single young hatched on about 17 September and intensive observations were continued through 28 November, with intermittent observations through 27 July. The young was still unable to lift its head at 2-4 days old, it began to pick at carcasses at 36 days, and was able to tear food by itself at 54 days. Wing and tail feathers started to grow after 37 days and it began branching near the nest at 71 days, finally fledging at about 87 days. After fledging, it stayed close to the nest, always within 170 m, for at least 225 days after fledging. A prey exchange was observed 225 days after fledging. It was preceded by 36 minutes of calling back and forth. The juvenile then left its perch and flew to the adult, grabbed the prey item from its talons without landing, and continued to a nearby perch. Like many forest raptors (Brown 1977), Ornate Hawk-Eagle appears to have a long period of parental dependency after fledging. Given an incubation period of 40 days and long periods of courtship, nesting, and raising a young to independence, Ornate Hawk-Eagles cannot nest more than once every other year.
No brood parasitism is known.
Populations and Demography
There is very little information on population or demography. Bierregaard (1994) reports a nesting density of one pair per 787 hectares in Petén, Guatemala. A published report of mortality due to shooting in Veracruz, Mexico, may include the only reports of ectoparasites from the species: a mallophagan (Menacanthus stramineusth), and a blood-sucking fly (Pseudolynchia canariensis).
Iliff, Marshall. 2010. Ornate Hawk-Eagle (Spizaetus ornatus), Neotropical Birds Online (T. S. Schulenberg, Editor). Ithaca: Cornell Lab of Ornithology; retrieved from Neotropical Birds Online: http://neotropical.birds.cornell.edu/portal/species/overview?p_p_spp=129556