Dietary biology of the Eurasian eagle-owl
In the Iberian peninsula, the Eurasian eagle-owl is part of a complex guild of predators that have evolved to survive mostly on European rabbits. Among this guild, golden eagles ("Aquila chrysaetos") were recorded per one study to rely on rabbits for 40% of the diet, the eagle-owl for 49% of the diet, the Spanish imperial eagle ("Aquila adalberti") for 50% of the diet, the Bonelli's eagle ("Aquila fasciata") for 61% of the diet and the Iberian lynx ("Lynx pardinus") for 79% of the diet. Elsewhere, the Spanish imperial eagle and eagle-owl are considered to outflank the golden and even the Bonelli's eagle as the most specialized avian predator of rabbits in the Iberian region. Other predators, such as common buzzard ("Buteo buteo"), northern goshawk ("Accipiter gentilis") black kite ("Milvus migrans") Iberian wildcat ("Felis silvestris tartessia"), red fox, stone marten ("Martes foina") and introduced Egyptian mongoose also prey heavily on rabbits in Spain, but are more generalized and less reliant than the above predators. All these powerful predators do not generally compete directly for food but conflicts may ensue over the rights to territories and nesting sites amongst the birds. Being nocturnal in activity, however, the Eurasian eagle-owl does not tend to compete as directly as do the three eagle species and even these are discreetly segregated by habitat preferences, the goldens preferring open, steep cliffs, the Bonelli's favoring densely vegetated areas mixed with rocky spots and the imperial favoring relatively flat open woodlands. Among these eagles, the golden eagle tends to have the most similar habitat preferences to the Eurasian eagle-owl and across a broad band of overlapping distribution, the two are considered nearly ecological equivalents by day and night. However, good-sized female golden eagles are up to twice as heavy as an average eagle-owl, so seem to have a considerable advantage in size and power. Conversely, to support their large size and large territory needs, the golden eagle cannot survive on small and diverse prey nearly as successfully as the eagle-owl. Among the Iberian peninsula rabbit-eating guild, the species with wider ranges, the eagle-owl and the golden and Bonelli's eagles, have had some degree of success living off of alternate prey following the devastation of the rabbit population due to rabbit haemorrhagic disease. The two rabbit predators endemic to Iberia, the Iberian lynx and Spanish imperial eagle, have been devastated by the reduction and other causes and both are threatened species today.
Martial eagle
While large accipitrids from around the world are credited with attacks on (almost always young) ungulates, perhaps no other species is as accomplished in this regard as this martial eagle. Over 30 species of ungulate have been identified as prey for this species, more species than are attributed to the perhaps more powerful crowned eagles and all the world's golden eagles, although in all 3 seldom more than 30% of the diet are comprised by ungulates in a given region. In Kruger National Park, the martial eagle is mentioned as the only bird considered as a major predator of ungulate species. A majority of the ungulate diet of martial eagles are comprised by small antelope species or the young of larger antelopes. Locally favored prey are the dik-diks, one of the smallest kind of antelope, and every known species may be vulnerable to this eagle. In Tsavo East National Park, Kirk's dik-dik ("Madoqua kirkii") were the second most numerous prey species and it was estimated that at least 86 dik-diks are taken in the park over the course of the year by two pairs of martial eagles. At an average of , these can provide a very fulfilling meal for an eagle family. Adults of other smaller antelope such as suni ("Neotragus moschatus") and blue duikers ("Philantomba monticola") are probably also taken with relative ease. In general, the young of other antelope are usually attacked, including newborns. Occasional ambush attacks or successful predations are reported on adults of much larger species despite young ones being rather more vulnerable, including klipspringers ("Oreotragus oreotragus"), steenboks ("Raphicerus campestris"), both species of grysbok ( on average), oribis ("Ourebia ourebi") and perhaps up to half a dozen larger duikers, potentially weighing from . One duiker dispatched via strangulation weighed an estimated , the largest known raptorial kill for any species on the African continent. Among extant birds of prey, only wedge-tailed eagles, reportedly capable of killing sheep and female red kangaroos ("Macropus rufus") weighing up to , and golden eagles, credited with taking adult female deer of several species with weights estimated at and capable of apparently dispatching domestic calves weighing up to , have larger kills attributed to them. Calves, including neonatal young, of the following antelope may also be included in their prey spectrum: impala ("Aepyceros melampus"), hartebeest ("Alcelaphus buselaphus"), bontebok ("Damaliscus pygargus"), common tsessebe ("Damaliscus lunatus"), springbok ("Antidorcas marsupialis"), "Eudorcas" gazelles, gerenuk ("Litocranius walleri"), bushbuck ("Tragelaphus sylvaticus"), grey rhebok ("Pelea capreolus"), kob ("Kobus kob") and mountain reedbuck ("Redunca arundinum"). These species can vary in weight from (i.e. gazelles) to (i.e. tsessebe) in newborns. For the newborn impala, weighing already , the martial eagle is the only bird considered to be a significant predator. Additionally, piglets of warthogs ("Phacochoerus africanus") (of which only the martial eagle among accipitrids is similarly mentioned as a significant predator) and bushpigs ("Potamochoerus larvatus") are taken.