Spanish Imperial Eagle Profile
Of the roughly ten species of eagle in Europe, there are two in particular that are exceptionally rare.
The Greater spotted eagle, Clanga clanga, has fewer than 10,000 breeding individuals but is spread over an enormous range, from Northern Europe to Eastern China.
This vulnerable eagle is considered one of Europe’s rarest, so it’s particularly sobering that the Spanish Imperial eagle has a tenth of its population and a fraction of its range: endemic only to Spain and Portugal.
Spanish Imperial Eagle Facts Overview
| Habitat: | Rocky, wooded areas, marshes |
| Location: | Breeding in Spain, Portugal, |
| Lifespan: | Up to 44 years in captivity |
| Size: | Around 83cm (33 inches) tall, 220 cm (7 ft 3 in) wingspan |
| Weight: | Up to 4.8 kg (10.6 lb) |
| Colour: | Pale straw colour in juveniles, blackish-brown in adults |
| Diet: | Rabbits, other small mammals, sometimes fish and birds |
| Predators: | None |
| Top Speed: | Unknown |
| No. of Species: | 1 |
| Conservation Status: | Vulnerable (IUCN) |
Spanish Imperial eagles aren’t nearly as widespread as their name suggests. Until recently, they were grouped as a subspecies of the Eastern Imperial eagle, but the moment they were recognised as their own species they became immediately one of the rarest eagle species on Earth.
Yet, these humble eagles are immensely significant predators in their ranges, balancing natural rabbit populations and helping the Iberian Lynx maintain the ecosystems they share.
While they declined to the point of extinction in Portugal, conservation efforts and reintroductions are showing serious returns and their numbers are now on the rise.
Interesting Spanish Imperial Eagle Facts
1. They’ve finally been recognised
This species was once thought to be a subspecies of the Eastern Imperial eagle and didn’t have its own species name until the early 2000s, but genetic analysis showed the two populations are distinct enough to be considered separate species, discovering the Spanish eagle as a unique animal, endemic to the Iberian Peninsula.
These eagles are 10% heavier than their Eastern counterparts on average and are pretty bulky for an Aquila eagle. They’re also less migratory, and a different colour, but their range is significantly lower than that of the Eastern Imperial eagle. 1
2. They only breed in Spain and Portugal
Unlike the Eastern species, this Imperial Eagle has a far humbler territory, occupying marshes and plains in central Spain and mountainous slopes in Portugal.
But while these are its chosen breeding grounds, the Spanish eagle will venture as far South as Mauritania, crossing over Gibraltar and through Morocco.
This isn’t so much of a migration as it is a rite of passage, and is usually the behaviour of juveniles who will spend their gap years travelling before settling down in a breeding location.
During this time they’re more adventurous with their food, branching away from their staple and trying the local dishes, which can comprise primarily of water birds. 2
3. They’re apex predators
Once settled in their home ranges, though, they’re much more single-minded.
Spanish Imperial eagles and Iberian Lynxes share a spot in the Mediterranean woodlands as top-tier predators. Both share the same food supply and avoid most of the competition by hunting with different methods.
Lynx spend very little time in the air, instead choosing to stalk prey from the ground, pouncing on it to deliver a killing bite. Spanish eagles attack from the sky, coming down hard with powerful talons that can snap or pierce the spine of their kill.
This isn’t always the end of it, though, as the mostly solitary eagle can be bullied off its meal by the more social, yet smaller red kites, or large vultures. Still, this eagle species is an important contributor to the population control of its prey species, most of which are rabbits. 3
4. Rabbits are their favourite meal
Rabbits are such an important food source to these eagles that their distribution can determine the eagle population dynamics.
Population densities, ranges, and reproductive success all depend to a high degree on the abundance and distribution of rabbits, which has been suggested as one of the limiting factors for this species’ relatively small number.
This makes them exceptionally rare for a bird of prey.
5. They’re one of the rarest raptors
Being endemic to such a small area, this species naturally has a low population, and this makes them vulnerable to extinction in ways that other species with wider distributions can resist.
Rabbits clearly provide a strong, but natural, limiting factor for the species, but this bird has a lot of more sudden threats, too. Electrocution and poisoning were the two most common causes of Spanish Eagle kills over the assessment period in one study.
Most of these poisonings were an inadvertent consequence of livestock protection, but in some cases were intentional.
Mitigation methods for electrocution have shown limited success, especially among immature eagles on their travels, and recently several have been found shot in both Portugal and Spain, showing that they are still persecuted there.
Human-influenced rabbit decline saw the food supply drop by 55% between 1973 and 2002, and the intensification of farming and irrigation throughout the range, as well as heavy urban development, has reduced their viable breeding sites and threatens a permanent restriction on their population growth.
This all sounds pretty grim for the poor eagle, but there is some very good news. 4
6. They’re making a comeback!
This species was once extinct in Portugal, but reintroductions have proved successful and the species as a whole is increasing in number.
Around 60% of the total breeding population is now residing inside protected areas, which is 10% less than it was in 2011 but still a powerful contributor to their conservation.
Modified powerlines have considerably reduced deaths from electrocution in this, and many other species, and in Spain this has been backed up by legal protection for birds that demands bid-safe powerlines and best practices accordingly.
Protection programs like the Flying High Programme in Spain and LIFE Imperial in Portugal focused on community education, habitat protections, and species management, and a successful reintroduction program involving 73 young birds in Andalucía has led to more than half the resident Imperial eagles being covered by conservation programs.
The reintroduced birds are now breeding and contributing to the recovery of the species. 5
7. They can be trained not to fly into power lines
Part of reintroducing young eagles involves the education of the birds, as well as the community. Conditioned learning programs work to train eagles to avoid powerlines entirely, greatly improving their chances as wild birds when released.
To do this, breeders use pylons set up with an electric fence running through them, conditioning the birds to be wary of the electricity and reducing their chance of landing on a real one after release. 6
Spanish Imperial Eagle Fact-File Summary
Scientific Classification
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Accipitriformes |
| Family: | Accipitridae |
| Genus: | Aquila |
| Species: | Adalberti |
Fact Sources & References
- “Iberian Lynx v Spanish Imperial Eagle”, Carnivora.
- “Spanish Imperial Eagle”, european raptors.
- planet earth (2023), “Spanish Imperial Eagle”,Youtube.
- “Spanish Imperial Eagle”, IUCN Red List.
- “Spanish Imperial Eagle Aquila adalberti”, oiseaux birds.
- “Reintroduction of the Spanish Imperial Eagle”, Fundación IBERDROLA Spain.