Hi Tom,
Undoubtedly there must have been a corridor from the main block of Mt
Kenya or Aberdares at some point, but Ol Donyio Sabuk has more
interesting avifauna than that would suggest.
The surrounding countryside of ODS is seasonally wet but more often
very dry savanna with it's characteristically different plant ecology.
To use the Brown-capped Weaver as an example of a montane forest
species present, the elevation of the plains surrounding ODS is
considerably lower than Nairobi. The Weaver has not been recorded in
Nairobi (though as would be expected it is on the higher nearby Kikuyu
Escarpment Forest) even though the habitat is here, and it would have
been expected, so I would imagine that it arrived (along with the
white-eye) considerably more than 150 years ago. The savanna itself
supports a very isolated endemic race of Green-capped Eremomela which
in itself suggests that the savannah has long been present. At its
base ODS has three very interesting isolated species, all of which
occur no-where close to ODS or Nairobi. Firstly the Eastern Bearded
Scrub-Robin (just discovered) occurs no closer than Kibwezi, the
Red-capped Robin-Chat also only found a few years ago for the first
time occurs disjunctly with the closest birds at Kiboko to the
south-east and the Mwea water-catchment area to the north. Also
Lead-coloured Flycatcher discovered ODS in the same time period as the
Robin-Chat has it's closest neighbours at Mwea Game Reserve to the NW
and nr Loitokitok to the south. It's sad but the single ocassions I
have met with this species at Mwea and ODS, I never made a note of
whether it was the coastal song or the inland song, which is a future
project and important to understanding the potential origin of the
population. We know that Mt Kenya at one point had a major forest
corridor that connected with the coast which enabled usually lowland
forms to reach highland forest where they formed endemic races and
obviously the biogeography is extremely complex. All this is to
suggest that the fauna of ODS is not at all recently established and
that it should be evolving differently from the montane and savannah
forms from which it originated. It's so sad that this mountain so
close to us has been neglected for so long, (as a point; the discovery
of the three species at its base), but good that there is now some
interest on the uniqueness it is slowly revealing,
Best for now
Brian

On 9/12/15, TButynski@aol.com <TButynski@aol.com> wrote:
> Hi,
>
> Historically, Ol Donyo Sabuk may not have been nearly as  'isolated' as it
> appears to be today.  100-150 years ago, there may  have been enough
> riverine forest and dense woodland along the Athi River to  connect Ol Donyo
> Sabuk
> with the Nairobi/Ngong/southern Aberdares  region...as well as along the
> Chania River...connecting Ol Donyo Sabuk with  the southern Aberdares.  If
> so,
> montane forest birds might have made  particular use of these former
> corridors during the colder, dryer, months  (e.g., June-August).
>
> Tom
>
>
>
> In a message dated 9/11/2015 4:22:38 P.M. E. Africa Standard Time,
> kenyabirdsnet-noreply@yahoogroups.com writes:
>
>
>
>
>
>
>
>
> Hi Brian,
>
>
> Thanks for the interesting info on the montane  white-eyes.  Yes, one would
>
> certainly believe the ol donyo white eyes and  most of the other montane
> spp for that matter, to be isolated and probably for  some time. It was
> actually something I was thinking about when I was up  there.
>
>
> That was the only photo that I managed to get.   Though given my proximity,
>
> I will probably be up there again in the near  future and will endeavor to
> get some more photos.  It would certainly  make for an interesting
> comparison with the kikuyu white eyes and more broadly  on the speciation of
> island
> populations.
>
>
> Let's chat after  you get back.
>
>
> Cheers, Darcy
>
>
> On Thu, Sep 10, 2015 at 10:15 PM, Brian Finch <_birdfinch@gmail.com_
> (mailto:birdfinch@gmail.com) > wrote:
>
> Dear  Darcy,
> I am in Madagascar at present and for the next three weeks. I  was
> fascinated by your Ol Donyio Sabuk report. and intrigued by  your
> white-eye. Birds in the Montane/Kikuyu groups when on mountain  islands
> seem to take on a racial identity or speciate. Britton gives  no
> mention of the species on such an isolated mountain, the range of  our
> more familiar kikuyuenis being a continuous distribution from Mt  Kenya
> to Nairobi highlands. No-where in this range is it isolated and I  am
> wondering if anyone has ever looked at the Ol Doniyo birds  before
> because there cannot be an interchange with the main distribution  and
> the birds should be isolated and evolving an identity. Do you have  any
> more images?
> Very best
> Brian
>
>
>
>
>
>
>
> On  9/7/15, Darcy Ogada _ogada.darcy@peregrinefund.org_
> (mailto:ogada.darcy@peregrinefund.org)   [kenyabirdsnet]
>
> <_kenyabirdsnet-noreply@yahoogroups.com_
> (mailto:kenyabirdsnet-noreply@yahoogroups.com) >  wrote:
>> Okay, I'm trying this again.  See below.
>>  ---------- Forwarded message ----------
>> From: Darcy Ogada <_ogada.darcy@peregrinefund.org_
> (mailto:ogada.darcy@peregrinefund.org) >
>>  Date: Mon, Sep 7, 2015 at 11:11 AM
>> Subject: Ol Donyo Sabuk 6 Sep  2015
>> To: _kenyabirdsnet@yahoogroups.com_
> (mailto:kenyabirdsnet@yahoogroups.com)
>>
>>
>>  Hi all,
>>
>> I was up Ol Donyo Sabuk yesterday.  Being  hopelessly dry in Thika, I was
>> hoping the mountain would produce  more birds.
>>
>> It certainly wasn't my best day up there, but I  managed some nice birds.
>>
>  I
>> finally managed to get some  photographs of the brown-capped weavers,
> which
>> I usually see, but  always in terrible light and with a strained neck.
>> Yesterday I was  very lucky to photograph both the male and the female.
> They
>> were  both doing their nuthatch-like feeding style of probing under the
>>  lichens as they scooted up and around a tall tree.
>> [image: Inline  image 1][image: Inline image 2]
>>
>>
>> I also managed this  rather distant photo of a montane white-eye.  As
>> further  support that despite the top of this mountain being only c.
>> 2100m
>>  the forests at the top support montane species.
>> [image: Inline image  1]
>>
>> Other non-montane species were groups of cabinis's  greenbul, and singles
>>
> of
>> augur buzzard, yellow-rumped tinkerbird,  brown-crowned tchagra.
>>
>> On the mammal side of things, I did  manage to see and photograph a troop
>>
> of
>> colobus monkeys.  While  seeing them there wasn't surprising, I can't
> recall
>> ever having run  into them before on the mountain.
>> Others were syke's monkeys and  baboons heard from afar, and dwarf
> mongoose.
>>
>> While Ol Donyo  is not the easiest park to see birds, it has a lovely bit
>>
> of
>> forest  at the top and apart from some semi-drunk hikers I didn't
> encounter
>>  anyone else.  Karibu Thika!
>>
>> Cheers,  Darcy
>>
>
>
>
>
>
>
>
> --
>
>
>
>
>
>
>
>
>
> Darcy Ogada | Assistant Director of Africa Programs
> The Peregrine Fund  | _www.peregrinefund.org_
> (http://www.peregrinefund.org/)
> P.O. Box 1629-00606, Nairobi, Kenya
> +254-722-339366
>
> Conserving birds of prey  worldwide
>
>
>
>
>
>
>
>
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>
>
>
>
> 
>
>
>