Dear All,
Dick Forsman has very kindly come back to me concerning the record I
posted on kenyabirdsnet of a Short-toed Snake-Eagle in NNP last
October. It mentions the features that supports the identity of a
young Black-chested Snake-Eagle rather than what I had misidentified
it as. This has been most useful, though the features necessitate
close contact with the bird, but I thought I would share them.

"Hi Brian,

Sorry for long wait, but I have been abroad for some time.

Thanks for the interesting images. However, to me this bird is not a
Short-toed (STSE), but a light form juvenile of Black-breasted
Snake-eagle (BBSE).

Superficially it looks like a STSE, but the barring of the underwing,
with a few distinct bands close together but quite far out on the
feather, does not match that species. Also the upperwing lacks the
sharp contrast between light coverts and dark remiges typical of STSE.
This is a juvenile bird, as shown for instance by its uniform
upperwing secondaries, and juv STSE would be perfectly fresh in
pristine plumage at this time of year, while this one is extremely
worn.

I remember having once seen a very similar pale (but fresh) juvenile
in Ethiopia, so I guess these pale ones must be quite rare.

all the very best,

Dick"

The points that separate this bird from a STSE are very fine and good
views must be available, thankfully for our bird the views were
nothing short of exceptional, but this bleached extensively pale young
form of Black-chested Snake-Eagle is not mentioned in the local
literature and it is a major pitfall for the unwary, as it was for us.
For example S&F ...Imm is brown above and mainly rufous below with
rufous underwing-coverts and indistinctly barred flight feathers.
Z&T... is more helpful in stating ...Transitional immature may show
whitish face and throat (although dark faced/white crowned in NNP
bird), dark breast band, and blotching on white underparts similar to
Short-toed Snake Eagle (unfortunately this is not illustrated). Leslie
Brown in Handbook BOA writes..... Immature dark brown above, rufous or
cinnamon below, sub-adult plumage obscure, but some probably almost
indistinguishable from {nominate} gallicus {Short-toed}. Again only
typical bird illustrated. Sasol Birds of Prey, Kemp illustrates and
describes typical rusty immature, and for sub-adult writes....
Distinct subadult plumage similar to adult plumage but sooty-brown
above. Below white or cream, marked with large brown blobs on upper
chest and broad rufous-brown bars on flanks and flight-feathers.
None of all this comes close to the NNP bird.

It would be great if the Raptorphiles out there who are familiar with
the characters that will separate this pale young plumage BCSE from
similar pale STSE would put pen to paper and share the knowledge as
this is an omission in what literature is currently available.

Best to all
Brian