Dear All,
This is a great find and a major extension in known range. Only the
Black Bishops share the combination of black throat and forehead. The
bird is the friederichseni “form” of Black Bishop. I did not know it
extended to the Lake. I have seen it Seronera, Ndutu to Olduvai. What
happens north of there I have no idea, but it sneaks into Kenya in
north Natron and at the now defunct Shompole Lodge, the birds used to
come and drink from the swimming pool which was quite a sight. They
were seasonally common there. I have taken much video, which enables
me to send grabs of the bird in flight. In Kenya from the Lake
Victoria basin westwards we have ansorgei. This extends south to
Rusinga Island, but doesn’t appear to get further south and although
there is habitat it just seems to drop out.
For me the important thing is that I do not believe these two birds
are the same species, or even that closely related. A situation
similar to Usambara Drongo, where things just do not make sense
visually, for birds to be under the same specific umbrella.
Friederichseni whilst it has to feed in grasses like the entire genus,
displays from the tops of acacias and crotons etc. and is a bird of
scrubland. Gierowi only ever exists in some form of grass, be it
native or in gardens of Maize, Sorghum, Sugar Cane etc… but always in
a grass even though it may use adjacent bushes for perching and
singing.
In Stevenson and Fanshawe the illustrations make the two look very
similar, with friederichseni having the red extending a little further
down the back, and gierowi with a tinge of yellow gradation from the
red of the nape. This is not accurate as the attached images will
show. The red continues in friederichseni to the rump, gierowi only
has colour to the extreme of the upper back but the hind collar is
bright yellow.
Best to all
Brian