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Rovørn (Aquila rapax) Tawny Eagle belisarius -
Stemmer kan høres her (eksternt link)
Lokalitet:
Bale Mountains (4000 m asl) - Etiopien
2012-12-15
Fotograf: Thomas Varto Nielsen - Se profil

Titel: Immature

Uploadet 2013-08-12 Publiceret 2013-08-12 Aquila rapax belisarius Tawny Eagle
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Kommentarer
Dick Forsman
14. aug. 2013 kl. 13:00
I think this is in fact a Tawny Eagle Aquila rapax. The Eastern Imperial Eagle has no such plumage, while Tawny Eagle has. This dark plumage type with pale streaks has often also been mistaken for a Greater Spotted Eagle.
Carsten Murmann
14. aug. 2013 kl. 16:20
Many thanks, Dick - presumably an adult(?). PS: Is there a special term for the slim Naked(!) brow or 'list' above the Eagle's eye, like on several other raptors ? [ The 'list' may shade/protect against e.g. sunlight, and may add a (human!) brave/serious touch to the face/physiognomy ] Yours ,,,,,,,,,,, C.
Peter Sunesen
14. aug. 2013 kl. 17:30
I'm not Dick, but as far as I know, the bare, protuding 'eyebrow' is simply called the supercilium. Depending on the position on the surrounding feather-tracts, the supercilium may, or may not, come across as more or less bare.
Peter Sunesen
14. aug. 2013 kl. 18:01
The pale shaft-streaks IMO indicate an immature. Furthermore it seems that the iris-colour is paler than what is normal for adults, but here I could very well be skating on thin ice:-)
Thomas Varto Nielsen
14. aug. 2013 kl. 22:25
Thank you very much to Dick Forsman for commenting on this bird. Eastern Imperial Eagle vs Tawny Eagle has caused me much trouble in Ethiopia, some birds I simply cannot identify...I have hundreds of pictures of such birds. The majority, if not all (!??), are likely to be streaked Tawny eagles. But I'm just not sure, especially because most of them are seen from October to April and only few (which must be Tawny) during the summer from May to September. It could be a coincidence, all though I have visited Ethiopia throughout the year, even many times during the rainy season from June to September. I will upload another picture of (most probably) the same bird taken the day after this picture. I spend all-most an hours each day watching this bird at very close range, and all though I did wonder if it was in fact a Tawny Eagle, I was finally sure of Eastern Imperial - but maybe I was completely wrong....? The bird was seen in flight once and I will upload a picture where some of the under wing is visible. Was I fooled by its large size because I saw it at close range? And because of what appears to be heavy streaking on body and wing coverts? I hope Dick Forsman and others with knowledge of how to identify these large eagles will share some of their knowledge. I will very much appreciate any hint of how to separate Imperial and tawny Eagles. Most field guides just mention that immature Imperial is streaked and Tawny eagle is not (but, like Dick mentions, many Tawny have streaks)
Dick Forsman
15. aug. 2013 kl. 08:35
First of all, the "shade" above the eye found in many diurnal raptors, and being especially conspicuous in eagles, is called the supraorbital ridge. I think supercilium is mainly used when referring to the plumage character, while this is an actual structure under the skin. As for the id. of streaked Tawnies vs. Imperials there is no simple rule, but the plumage sequence of Imperial is well-known and the various plumages are shown in many books. The first three plumages are rather similar to the juvenile plumage, being pale sandy brown with more or less prominent streaking (streaking can be almost lacking in 3rd plumage). After these immature plumages the birds become first heavily mottled, losing the distinct streaking, then turning dark as sub-adults. Already in the mottled stages the head turns Golden Eagle-like and the tail gradually becomes grey with a broad dark tip. The streaked Tawny Eagles, which I have seen regularly in Ethiopia, are generally more uniformly dark and always lack the typical head and tail of an older immature Imperial. Typically the body feathers are dark with rather distinct pale streaks,mostly on breast and upperwing coverts, something you never see in dark (subadult/adult) Imperials. In short, if a darkish eagle lacks the Golden Eagle-head and the bi-coloured tail, it cannot be an Imperial. If it is streaked it has to be a Tawny (or a Greater Spotted!). Regarding this bird I'm sure it is a Tawny, an adult to be more precise. Eye colour in Tawny varies from dark to light also in adults, but everything in the plumage suggests an adult bird (such as the light "hackles" in the neck). Many thanks to Thomas for posting these interesting images on the site!
Peter Sunesen
15. aug. 2013 kl. 11:07
Thanks to Dick for sorting out this id-complex. It sounds encouragingly 'easy-peasy'.....shall remember the supraorbital ridge:-)
Jan Jörgensen
15. aug. 2013 kl. 15:50
Supraorbital ridge The ridge just above the eye; the brow bone. Immature birds are frequently not seen with a developed supraorbital ridge. here JanJ
Peter Sunesen
15. aug. 2013 kl. 16:35
I believe the supraorbital ridge is developed along with the general skeletal structure while the young bird attains full size and plumage. Raptors certainly need all their faculties when they set out to hunt independently from the parents. IMO the Buteo seems to have a fully developed 'eyebrow'.
Thomas Varto Nielsen
18. aug. 2013 kl. 21:50
The comments here, together with many e-mails I have received, all suggest this is a Tawny Eagle. Some birders are sure its a Tawny, some are are in doubt - no one are certain it´s an Imperial! So I think the name can be changed to Tawny Eagle. There is some disagreement about the age of this bird; is it an adult or an immature?? I have uploaded another photo showing the primaries. Perhaps this can prove the bird is actually an immature? Netfugl må gerne flytte de to billeder af denne fugl til Rovørn. Foreløbig må titlen Immature gerne blive stående.

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