Birds in Spain
Identification and occurrence
El Hondo has been the best place in Spain to watch wintering Greater Spotted Eagles (Aquila clanga) the last years. A few individuals have stayed all winter long, some of them coming ringed or GPS tagged from Baltic countries where they have bred. The presence of Lesser Spotted Eagle (A.pomarina) though, is a much rarer event, so far unprecedented in winter in the whole E of Spain, and there are only a few records in S Andalusia.
Since 3rd of December 2016, a presumed 1w of Lesser Spotted Eagle (Aquila pomarina - Clanga pomarina for some authors -) has been seen at El Hondo Nature Park (Alicante). As it is known, the hybridization in between the species Lesser Spotted Eagle (LSE) and Greater Spotted Eagle (GSE) is highly likely to happen. So, since the beginning, this individual was submitted to a very rigorous analysis before concluding with its identification. In this note we include a number of photos and discuss its identification process during its staying at El Hondo in late 2016 - early 2017.
The bird was seen for the first time on December 3rd, by Alex Alamán, Roque Belenguer, Germán López and Jana Marco, at the southern part of El Hondo Nature Park (Alicante). First, the bird (that by its size reminded us of a Booted eagle Aquila pennata), was spotted on a branch by Alex, who very quickly alerted us that it seemed to be a kind of Spotted Eagle Aquila sp. Then, the bird started flying in circles above us. The plumage features, its structure, its size and the way it was flying, made us think about LSE. But surprisingly, 20 days later, on December 24th, we saw it again in the exact same place. This sighting of the same bird again made doubts appear… Was it the same bird that we saw before? How was it possible that a LSE was staying here in winter? Could it be a hybrid? Considering that unlike the GSE, the LSE are long-distance migrants, the presence of a pure LSE during the winter period here, could be the most north wintering area ever described for this species, which by late December should be in the south of the Sahara. For that reason, the idea of a hybrid eagle between GSE x LSE was suggested. We saw the bird again on January 3rd and 4th (Jacobo Ramos, Irene Arnaldos, Pablo Santonja, Antonio Saez, Jana Marco et al). By that time, Juanma Pérez-García and I had already contacted Urmas Sellis from the University of Live Sciences in Tartu, Estonia. He has a wide experience studying these species, both GSE and LSE and even their hybrids! He is also part of the research group that marked the famous GSE Tõnn, which has spent every winter at El Hondo Nature Park since 2008.
The seven known observations of the bird until late January 2017 at el Hondo are:
Bird identification process was achieved following the hints described in the interesting paper published by Jan Lontkowski and Grzegorz Maciorowski in Dutch Birding.
1. Presence of only 6 ‘fingers’, showing a short 7th primary.
2. Presence of two light ‘commas’ under the wing, near the carpal joint.
3. Same generation of remiges (flight feathers) that indicates the individual is a juvenile. Once we determined the age of the bird (juvenile), we realized that the pattern of white spots on the upper wings and body didn’t match the classic pattern of the GSE but instead, the LSE. This bird can only be confused with a 3cy of GSE. Both species show a similar plumage (LSE juvenile and 3cy GSE) with small white spots on the bottom of the wing and with no spots at all on the rest of the body (like GSE juveniles). But if it was a 3cy of GSE, it must show flight feathers from several generations.
4. Its flying silhouette was graceful and thinner than a GSE.
5. The barred pattern of secondaries and inner primaries, was more similar to a LSE pattern than to a GSE pattern, with strong presence of black lines over a white background with thin white spots at the end of the feathers both visible in the upper wing and under the wing.
1. The bird showed a contrast of brown colors between wings and body feathers. It is the classic coloration for LSE, while the GSE would show homogenous darker coloration.
2. Considering that the bird was a juvenile, the pattern of white spots didn’t match the typical pattern of GSE, which has bigger spots covering both the wings and body. In this case, the shape and size of the white spots matched the LSE.
3. The bird had a thinner and smaller bill than GSE.
4. It showed rather narrow ‘trousers’ without spots.
5. It had a smaller structure and size … It could even remind us of a booted eagle (see pictures).
6. The bird showed a small pale patch on the nape. Sometimes, this pale patch can consist of only a few feathers. In this case, the patch was very small and it was one of the reasons that made us think about the hybrid possibility, but according to the experts that feature needs to be looked at carefully.
Despite all the features that indicate this individual is likely to be a Lesser Spotted Eagle, it is impossible for us to be positive about it without genetic analyses…. Especially since we are aware of the large extent of the hybridization problem that affects both species. Bird identification is not as easy as it seems. We must keep in mind we are no longer working with pure individuals but hybrids and their descendants too. We are still working on this topic, sending the pictures of this bird to several more experienced ornithologists. The bird is going to remain identified as “presumed Lesser Spotted Eagle” unless we get any different data.
All photos below: © Jana Marco except the last three @ Rolf Karlsson
Note here the medium chocolate-brown back and upperwing contrasting with the blackish great coverts, remiges and rectrices.
The presence of only 6 ‘fingers’, showing a short 7th primary and the two light underwing ‘commas’, near the carpal joint, are characters pointing towards LSE.
Small structure and size. Comparison in between a Booted Eagle Aquila pennata (up) and the Lesser Spotted Eagle A. pomarina (below).
The eagle nape shows a small pale patch. Sometimes this pale patch can consist in only a few feathers, as in this case.
The contrast in between the brown lesser and median coverts and the blackish greater coverts and secondaries is very sharp and visible from afar.
Graceful flying silhouette and thinner than a GSE.
Barred pattern of secondaries and inner primaries are those of a LSE pattern, with strong presence of black lines, regularly spaced over the entire length of the feather, with a pale tip at the end.
Clear contrast between light brown of body feathers and underwing coverts and blackish brown tones of remiges and rectrices.
Photos from © Rolf Karlsson obtained on 28.12 at El Hondo too:
Thanks to Urmas Sellis for his great help in identifying this individual. Thanks to Juanma Pérez for correcting and reviewing the article and also working on the bird identification. Also thanks to Rolf Karlsson for providing the three final photos once the first version of this page was published. Finally, thanks to all those ornithologists who have shared their opinion with us.
Marco, J. 2017. Identification and occurrence. Presumed Lesser Spotted Eagle (Aquila pomarina) wintering at 'El Hondo' Nature park, Alicante. Retrieved from http://www.rarebirdspain.net/arbsi046.htm
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Presumed Lesser Spotted Eagle (Aquila pomarina) wintering at 'El Hondo' Nature park, Alicante.
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