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Borneo raptor (1 Viewer)
- Thread starter monkir
- Start date
Jean FRANCOIS
Well-known member
Blyth's or Wallace's HE.
Where was it in Borneo?
Jean
Where was it in Borneo?
Jean
Last edited:
Jean FRANCOIS
Well-known member
Last edited:
I would go for Wallace's.
It's similar to a number of images on OBI, including this one:
http://orientalbirdimages.org/search.php?Bird_ID=894&Bird_Image_ID=141656
Very pale, with even lighter blotches on the underparts and a pale crest.
There are very few images of juvenile Blyth's online - see here: https://search.macaulaylibrary.org/catalog?taxonCode=blyhae1&q=Blyth's Hawk-Eagle&age=i,j
The bird photographed by Timothy Forrester must be 2nd calendar year, so is not comparable, but the nestling photographed by Eugene Prewitt has some dark feather centres on the underparts and much darker upperparts with some pale edges. Jannie Tan's image of the juvenile jumping out of the nest is too small to make much out but looks to be of a different coloration.
A similar young bird here - again, note the dark brown upperparts with pale edges: http://orientalbirdimages.org/search.php?Bird_ID=891&Bird_Image_ID=2373.
This species seems to lack the pale coverts typical of Nisaetus eagles.
It's similar to a number of images on OBI, including this one:
http://orientalbirdimages.org/search.php?Bird_ID=894&Bird_Image_ID=141656
Very pale, with even lighter blotches on the underparts and a pale crest.
There are very few images of juvenile Blyth's online - see here: https://search.macaulaylibrary.org/catalog?taxonCode=blyhae1&q=Blyth's Hawk-Eagle&age=i,j
The bird photographed by Timothy Forrester must be 2nd calendar year, so is not comparable, but the nestling photographed by Eugene Prewitt has some dark feather centres on the underparts and much darker upperparts with some pale edges. Jannie Tan's image of the juvenile jumping out of the nest is too small to make much out but looks to be of a different coloration.
A similar young bird here - again, note the dark brown upperparts with pale edges: http://orientalbirdimages.org/search.php?Bird_ID=891&Bird_Image_ID=2373.
This species seems to lack the pale coverts typical of Nisaetus eagles.
Andy Adcock
Worst person on Birdforum
Do you mean Sukau or is there a Sakau?
Blyth's or Wallace's Hawk Eagle is a good identification in this case, in my opinion. Some characters separating these two in juvenile plumage have been published, but not very convincing. Fresh juvenile Blyth's has almost coppery colouration, almost like fresh juvenile Montagu's Harrier, as demonstrated by the photos, but it is just the kind of colouration which fades a lot before the next moult. Probably they are distinguishable, even if very similar, but lack of material causes problems when trying to evaluate the characters. Certainly identified individuals are scarce. By the way, the bird photographed by Timothy Forrester in the eBird link is an adult Wallace's Hawk Eagle.
The OP bird looks like a dead ringer for some of the juvenile Wallace's on OBI, that's all I can say.
I never considered Timothy might have got the ID wrong, to be honest. I know him a little bit and he's a pretty competent observer. In addition, he spends most of his time in Borneo, based at Kinabalu HQ, so he should know these birds pretty well. I'll let him know.
I never considered Timothy might have got the ID wrong, to be honest. I know him a little bit and he's a pretty competent observer. In addition, he spends most of his time in Borneo, based at Kinabalu HQ, so he should know these birds pretty well. I'll let him know.
One way of telling the juveniles of these two species apart might be tail pattern. Eaton et al (Birds of the Indonesian Archipelago) shows juvenile Blyth's with 4-5 narrow, evenly-spaced bands on the undertail, and this is also explicitly stated in the text. This would be borne out by this rare image (there is another at no.9) of a juvenile in flight: http://orientalbirdimages.org/search.php?Bird_ID=891&Bird_Image_ID=93168. Juvenile Wallaces's, on the other hand, is shown to have a broader terminal band and 1-2 bars only above that. The OP bird seems to exhibit the latter pattern.
I also found this remarkable webpage with some images of what are claimed to be juvenile Blyth's. The first bird (2010) is extremely pale, almost white. There are only three tail bars of even width, so I wonder if it's correctly identified. Then there are two images of another juvenile, taken in 2011, with a black crest, although the tail is not visible. The last bird, photographed in 2011, also looks pale and shows a dark crest - I don't know if that signifies anything. I assume birds on the nest were correctly identified, as the adults must have also been seen.
https://singaporeraptors.wordpress.com/blyths-hawk-eagle/
Lastly, the subadult on this page looks more like what I would expect a 2nd or 3rd cy bird to. The bird in flight on OBI is captioned subadult (2nd-3rd cy), but I find that hard to believe. Several images on OBI show birds on the nest in January or February, so could this bird have been fledged around then and could it be a 1st cy bird, about 6 months old?
I also found this remarkable webpage with some images of what are claimed to be juvenile Blyth's. The first bird (2010) is extremely pale, almost white. There are only three tail bars of even width, so I wonder if it's correctly identified. Then there are two images of another juvenile, taken in 2011, with a black crest, although the tail is not visible. The last bird, photographed in 2011, also looks pale and shows a dark crest - I don't know if that signifies anything. I assume birds on the nest were correctly identified, as the adults must have also been seen.
https://singaporeraptors.wordpress.com/blyths-hawk-eagle/
Lastly, the subadult on this page looks more like what I would expect a 2nd or 3rd cy bird to. The bird in flight on OBI is captioned subadult (2nd-3rd cy), but I find that hard to believe. Several images on OBI show birds on the nest in January or February, so could this bird have been fledged around then and could it be a 1st cy bird, about 6 months old?
Yes, you are probably right. It seems that the tail pattern of juvenile Wallace's is not too different to that of adult, only that the dark bars are narrower and less clear-cut. The OBI young Blyth's from Cameron Highlands, July, has just started to moult primaries, with most feathers still juvenile. Most raptors, also tropical breeders, are in this stage when about a year old. Wells (The Birds of Thai-Malay Peninsula) states that the species is a northern winter breeder, with no young unfledged after the end of February. This fits well to the photos you referred, but not perfectly to the plumage state of this bird. The subadult Blyth's from Panti, March has yet to drop two outer juvenile primaries and many secondaries. It is easy to believe that it is a year older than the Cameron Highlands bird. (It is hard to use calendar-year terminology in birds which may be born around new year!)
