Dear All,
With the recent recognition (not all authors by any means) of Lybius
senex, the Snowy Barbet being given recognition as distinct from the
White-headed Barbet Lybius leucocephalus, Nigel Hunter and I decided
to try and get more information on our local White-headed Barbet of
the race albicauda, living almost alongside our more familiar Snowy
Barbet. To give an idea of how close they come, Snowy Barbet is on the
eastern slopes of the Ngong Hills, thence eastwards from there, whilst
the race albicauda of White-headed Barbet is in figs and vegetation
amongst the huge boulders on the top of the Ngong Hills then on the
western slopes into the Rift, where amongst figs in the lava valleys.

We thought we would try the large dam below Kisamese, where we had
seen them in figs growing amongst boulders on previous occasions, but
there was no sign of them. We continued away from the Ngongs out
towards the junction with the main road back to Ngong Town, but before
getting there we had four flying past the car. We pulled to a halt,
and after a while they returned and I was able to get some nice photos
and video of a pair. The whole area was low scrub dominated by Acacias
sayal, tortilis and mellifera, with an abundance of Leleshwa. The
birds were sitting in a small tree by the side of the road, which
proved to be the only fig for a long way. As can be seen from the
image, this bird differs from senex, in having a broad very dark brown
breast band instead of immaculate white underparts, and white tips
giving a spotted effect, to the wing-coverts and secondary coverts,
rather than the uniform dark brown of senex.  We were hoping that the
birds would call so that they could be videoed doing so, but they
remained silent.

Strangely one of the pair vanished and it was hoped that they might
have a nest. We continued towards Endashant, and on return stopped to
look at the tree, and there was one of the pair staring out of its
nest hole just 2 ½ m from the ground. So it was an excellent breeding
record.

A study of the literature leads to a misleading distribution for all
three Kenyan forms of the White-headed Barbet complex. You cannot
blame authors, because they are collating information available, gaps
in ranges are merely because they are either real or if they had been
seen, the information was never made public. The most recent fairly
detailed coverage for the ranges of senex, nominate leucocephalus and
albicauda is found in Zimmermann & Turner. If we look first at
albicauda which is what the breeding birds were today, it states
…“Lolgorien, Mara GR and Loita Hills through interior n. Tanzania to
Serengeti, Lake Manyara,Tarangire and Arusha NP’s, and the North Pare
Mountains; also in Taveta and Bura (Taita Hills district) in se.
Kenya. Formerly along the Voi River and occasional at Mombasa.” There
is no mention at all of the birds occurring along the east wall of the
Rift from the Tz border to Nairobi.

It’s over ten years since I saw my first local ones, they were in
hidden valleys between Ol Tepesi and Suswa near a place called Eremit.
These valleys also held other species that are otherwise not recorded
along the Magadi Road, such as Southern White-faced Owl, Arrow-marked
Babbler, Grey-crested Helmet-shrike and were rich in birds.
Subsequently I found them quite regularly on the top of the Ngongs
behind Ngong town, and in lava valleys further out from the Ngongs in
the Rift. I have not heard of any recent observations from further
east, I would expect them in the groundwater forest of Loitokitok on
the Tanzanian border though. In the Mara they are mainly restricted to
the Oloololo Escarpment, never venturing away from here into the
plains or even along the Mara River forests.

The distribution of the Nominate leucocephalus is stated, “ …ranges in
w. Kenya from Ruma NP (Lambwe Valley) and Kisumu north to Mt Elgon and
the Kongelai Escarpment.” This is only a part of the range, here
restricting them to extreme W Kenya along the Uganda border, but they
range eastwards reaching Kerio Valley, Mogotio near Baringo, where
they are in figs bordering the irrigation area, and at times even in
Nakuru NP.

For senex it states “ …senex in the central Kenyan highlands, mainly
east of the Rift Valley (this is a rather strange comment as every
location given is east of the Rift Valley), at Meru, Embu, Nairobi,
Thika, Kitui and the Chyulu Hills. To this we can add Kiboko (near
Hunter’s Lodge), rather than have the Chyulus sound like a disjunct
population.

It’s quite likely that the nominate and albicauda are indeed races of
the same species, now called White-headed Barbet. The tail colour is
really the only thing that visually separates the two, and then race
lynesi in Tanzania as a two coloured tail. The range of White-headed
Barbet extends from SW and S Kenya and N Tanzania, much of Uganda, S
Sudan and S C.A.R. It does not occur in the Congolian forests, but
reappears in the higher lands of West Africa. Throughout this range,
the bird does not differ in plumage apart from tail colour of eastern
albicauda.
Also in Zimmermann & Turner, it states that senex and albicauda
hybridise freely where the ranges meet. Personally I have never seen a
senex-like bird with isolated dark spots on the breast or white
markings in the wings, which is what a hybrid would look like, and we
wish to challenge this statement. Remembering that the dark-breasted
birds do vary in amount of colour, and the white spotting on the wings
also varies in coverage just as individual or maybe age variation.
(Google Images has a fine selection of albicauda, see how they vary).
Also that it is unlikely that since original collection these alleged
hybrids have ever been dna sequenced, to confirm the claim of
hybridisation.
The calls of senex and the White-headed group are different, but sadly
today we could not get the recordings we required.

Attached are images of todays birds and a few others, and the Stilts
flew over whilst I was writing this!

Best to all
Brian

KEY

Top four nesting birds below Ngong.

These are albicauda, note how the belly and the wings are virtually
black, there are not broad white spots on secondary coverts almost
forming a wing-bar.

Second Row left.

These are nominate leucocephalus from Kerio Valley, not given as part
of distribution. Apart from the all dark tail, note how the overall
colour of the dark areas is not blackish but reddish-brown. Also very
broad white tips to secondary-coverts almost form a broad wing-bar.

Second Row right.

A pair of nominate from Kongelai. Again apart from all dark tail, dark
body-feathers more red-brown than blackish, and broad white wing-bar.

Third Row left.

Nominate from Nakuru NP, same reddish-brown, and conspicuous white
wing-bar. The tail looks dark with white-outertail feathers, this
might be an artefact as I never noticed this in the field and thought
it was all blackish. Other features suggest nominate and not
albicauda.

Third Row right.

This is senex from Kiboko. All white underparts and tail, all dark
unmarked wings.

Fourth Row

This is senex from Nairobi, features as above.