Middle Spotted Eagle at Taqah, Oman

“Houston, Tranquility Base here. The Eagle has landed” – Neil Armstrong.

Khawr Taqah used to be one of the best places in Oman to see the scarce Small Pratincole in winter, but the monsoon that devastated the south of the country in summer 2018 destroyed the coastal lagoon and nowadays the area consists mainly in a pretty extensive steppe-land and some weird pools surrounded by reedbed in what (I suppose) was meant to be a park. It’s worth accepting it: Taqah has lost some of its appeal, but maybe not its potential to produce interesting and memorable observations. This place currently provides an extensive coastal heathland, a globally endangered habitat always rich in foraging raptors. As soon as we arrived, we immediately detected three big eagles surrounded by House Crows, obviously scavenging on a carcase. Two of them were immature Eastern Imperial, but the other wasn’t as obvious. Although we initially identified it as a Greater Spotted Eagle based on likeliness, we soon realised it showed some very obvious hybrid features.

Despite I don’t have much first-hand experience with Spotted Eagles, especially Greater, a big percentage of the birds seen in the Iberian Peninsula (around 10/year) show at least some of these features, so as a Rarities Committee member I’ve always been compelled to dig in a subject that I had never felt particularly attracted to. Thankfully, Lontkowski & Maciorovski Dutch Birding paper on the matter, published back in 2010, is pretty complete and soon became a must-read to understand the variation within the 2 species and to assess birds like these (by Javier Elorriaga) and like this (in Spanish; by Àlex Ollé & Guillermo Rodríguez). Since you don’t quite often get such great photo opportunities with these hybrids, I thought it could be interesting to share here the pictures I took, accompanied by merely descriptive captions.

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1cy hybrid type Greater x Lesser Spotted Eagle Aquila clanga x Aquila pomarina. Khawr Taqah, Oman, February 2019. © Marcel Gil Velasco. The most striking of the bird sat on the ground was the small size of the spots. From the distance it looked almost uniform brown, with a paler head. Closer views revealed white and creamy spots on GCs, MCs and LCs. Although the wear had already reduced the spots, their original size must have been still beyond GSE variation.
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1cy hybrid type Greater x Lesser Spotted Eagle Aquila clanga x Aquila pomarina. Khawr Taqah, Oman, February 2019. © Marcel Gil Velasco. Structurally, it gave a small-headed impression. The bill, however, was still quite powerful in my opinion. The combination of these two features probably reduced the small-billed impression typically given by pure individuals of either species. Paler head contrasting with darker (although still warm) upperparts is also well visible here. The spots on upperwing coverts look like fine streaks here (and under most views we got), contrasting with the nice and broad tear-shaped spots on pure GSE and approaching LSE. In the other hand, the spots on leg feathers are still quite big in proportion.
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1cy hybrid type Greater x Lesser Spotted Eagle Aquila clanga x Aquila pomarina. Khawr Taqah, Oman, February 2019. © Marcel Gil Velasco. The bright golden streaks on the nape were just as noticeable as in a Golden Eagle, a feature shared by the bird in Catalonia seen some years ago, although not to that extent. The streaking is that dense that it creates a solid golden patch on the nape, surrounded by stitched neck and crown. This pattern is described as exclusive of pure LSE in Lontkowski & Maciorovski’ paper.
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1cy hybrid type Greater x Lesser Spotted Eagle Aquila clanga x Aquila pomarina. Khawr Taqah, Oman, February 2019. © Marcel Gil Velasco. Uppertail coverts have been described as key to clinch the id of these eagles, so I was particularly keen on getting photos of these feathers. The white isn’t restricted to the tip of the feather but still far from the almost entirely white UTCs of a pure GSE. Tail feathers show a well-defined pale tip as in LSE, missing the transition area typical of GSE.
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1cy hybrid type Greater x Lesser Spotted Eagle Aquila clanga x Aquila pomarina. Khawr Taqah, Oman, February 2019. © Marcel Gil Velasco. The lenght of P4 was visible when the bird stretched its wings for a short flight. It’s quite long in my opinion, better fitting GSE. The secondaries look entirely plain here in terms of barring, but the pure white tip was prominent and well-defined.
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1cy hybrid type Greater x Lesser Spotted Eagle Aquila clanga x Aquila pomarina. Khawr Taqah, Oman, February 2019. © Marcel Gil Velasco. Although not perfectly on focus, the secondaries can be assessed here. They show a very subtle barring that doesn’t reach the tip of the feather, dominated by a quite well-defined white tip. Whether this barring is enough to rule out a pure GSE or not doesn’t seem to be clear. There seems to be a lot of variation within GSE in that respect, following a W-E axis (barred secondaries in the W and more uniform in the E) that itself explains a lot of what’s going on between these two species. The rump is visible here too and interestingly some feathers show a pure white tiny spot on the tip together with a contrastingly paler outer web, probably reminiscent of GSE influence.
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1cy hybrid type Greater x Lesser Spotted Eagle Aquila clanga x Aquila pomarina. Khawr Taqah, Oman, February 2019. © Marcel Gil Velasco. Such a great observation usually has this sole problem: the lack of underwing views. This is all we managed, which isn’t much, but enough to see the largely spotted flanks. I was quite surprised by the extension of the spots in this area of the plumage, given how small they are elsewhere. Sadly, the exact pattern of the secondaries remained undisclosed, but they look fairly uniform here. The white bases of underprimary coverts are also visible, but the rest of the underwing looks rather plain brown.

As usually happens with hybrids, in terms of plumage appearance, anything within GSE and LSE seems to be possible. Most birds show a plumage closer to one of the two species, whereas others show a puzzling combination of features. This variation among hybrids has typically been linked to its generation and indeed there seems to be a tendency towards that. However, hybridisation always entails a component of unpredictability so detailed studies of such individuals can help filling some gaps. In this case, the bird shows some features that are meant to be exclusive of LSE (especially nape patch) whereas others are obviously GSE-like. To understand how far can a hybrid get in every feature is key in order to avoid considering diagnostic some features that are not.

PS: A bit of publicity here for the new book that just got published by good friend Àlex Ollé (together with Fran Trabalon). Raptors of Europe. Both are great birders and, needless to say, raptor lovers. Spanish only yet but still worth it for every serious European (and worldwide) raptor-watcher. Go and buy it!

 

 

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