Mystery Eagle: Spanish Imperial Eagle?

The following is a series of photos taken by Dutch bird photographer Frank Dröge on Thursday 18th March at our Lammergeier feeding station and photography site in the Pre-Pyrenees of Catalonia, Spain.

Juvenile Spanish Imperial Eagle, Aquila adalberti ?

Juvenile Spanish Imperial Eagle Aquila adalberti in the Pyrenees.

Is this a juvenile Spanish Imperial Eagle, Aquila adalberti?

Eagle thought to be a juvenile Spanish Imperial Eagle Aquila adalberti.

Probable juvenile Spanish Imperial Eagle Aquila adalberti

Probable juvenile Spanish Imperial Eagle Aquila adalberti with juvenile Lammergeier Gypaetus barbatus

Probable juvenile Spanish Imperial Eagle Aquila adalberti. All photographs copyright of Frank Dröge.

They show what is obviously a juvenile Aquila eagle, but one which is not a Golden Eagle Aquila chrysaetos, the only Aquila eagle that could be expected in the region. The combination of the pale, milky-brown coloration, the general lack of streaking, the all dark tail, the degree of contrast on the outer and inner halves of the outer primaries and the deep, heavy bill have led us to conclude that it is a juvenile Spanish Imperial Eagle Aquila adalberti.

However, to get here we had to consider several candidates, including Eastern Imperial Eagle Aquila heliaca, the fulvescens form of the Greater Spotted Eagle Aquila clanga, and even the Tawny Eagle Aquila rapax.

The main obstacle to 100% confidence in Spanish Imperial Eagle is the pale coloration, much paler than the few juveniles that Frank and I have seen between us. Could this be due to wear or bleaching?

We would be glad to hear any comments that can shed light on this matter.

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2 Responses to “Mystery Eagle: Spanish Imperial Eagle?”

  1. Pedro Lourenço Says:
  2. From my experience I have noticed that juvenile Aquila adalberti are often very pale. I’ve actually seen one just yesterday in SE portugal which was almost as light as a tawny eagle, but was definitely an imperial eagle.
    I wonder if there is any type of geographic variation within the Iberian Peninsula, or just a matter of random individual variation.

    cheers
    Pedro

  3. Mathieu Says:
  4. I too have seen a fair number of juvenile Spanish Imperial Eagles with a pale plumage. I would assume it’s just part of the early stages of growth. But, I couldn’t say for certain. Perhaps I was mistaken before, but I always felt sure!

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