Fw: [tanzaniabirds] A Racquet-tailed Roller? in the Mara

From: Brian Finch <birdfinch@gmail.com>

Date: 2011-10-11 12:37

Subject: Fw: [tanzaniabirds] A Racquet-tailed Roller? in the Mara

">----- Forwarded Message -----
From: Brian Finch <birdfinch@gmail.com>
To: tanzaniabirds@yahoogroups.com
Cc: Itai Shanni <itaisha1@yahoo.com>
Sent: Tuesday, 11 October 2011, 16:42
Subject: Re: [tanzaniabirds] A Racquet-tailed Roller? in the Mara

Dear All,
I have attached two images. The first is a Racquet-tail from Kilosa.
This is a blue form, there was a discussion about the actual
existence of “races” some time back. The usual form I have seen around
Kilosa is pink-breasted. I cannot imagine a different race wandering
into anothers range, but there is an actual existence of “races”
“weigallii” or “spatulatus” isn’t the issue here.

The second image is an Abyssinian Roller from Lokichogio, without its
tail streamers.

I completely agree with Adam, even to the spelling of racquet!

In a previous email to Itai, after the image was sent to me I gave a
list of reasons why I would like to see this bird submitted to the
rarities committee as the first Racquet-tailed Roller for Kenya. They
were “…The bird looks small, the bill is slight, the extensive white
forehead and forecrown, broad white eye brow, the contrasting black
line from side of nape to and through eye, complete lack of visible
blue on wing, brown of back extending as same colour to back of nape
and neck, all blue underparts, I can see no reason why this is not a
blue form of Racquet-tailed Roller regardless of the lack of
racquets!”

Unlike any other eastern blue roller, RTR is the only species that
completely lacks pale blue on the closed wing, as with Adams image, my
Kilosa image and the Mara image, all showing brown/ deep blue,
shoulders and coverts. I know very little about genetics, but surely
no hybridisation between Lilac-breasted, Eurasian or Abyssinian is
going to throw brown coverts into the mix and change the extensive
silver blue areas to deep blue.

Lilac-breasted and Abyssinian show blue on outer and many inner
retrices, again any hybridisation should surely result in a
continuation of the blue, not create random dark tail feathers.
Racquet-tailed has reduced pale blue in the tail. Uniquely amongst the
group in EA, all the tail feathers are broadly dark tipped. The only
pale blue in the tail of RTR is restricted to the bases of a few sets
of outer retrices. On a perched bird with the central feathers
covering much of the outer ones, hardly any pale blue would be visible
if at all. There is no pale blue visible on the tail in the image of
the Mara bird. Refer to the image of the moulting Abyssinian and the
amount of blue still visible even with the outer retrices missing.
Also note that the amount of pale blue visible on the closed wing of
this bird that is so extensive that it completely hides the underparts
in case you think it is the belly you see.

Colin (B) mentions the large amount of white on the forehead as a
support for Abyssinian. RTR does show the forehead whitish, and this
streaks back broadly above the eye, contrasting with the black line
from lores through the eye adjoining the nape that is concolorous with
the back. Abyssinian shows white forehead as well, however this white
band stops above the eye as a narrow semicircle, behind this the head
is all blue. It shows dark lores, which extend beyond the eye and stop
abruptly before reaching beyond the side of the face, not sweeping
back to and joining the nape, which of course is entirely blue in
Abyssinian, again as with Adams image, my Kilosa image and the Mara
image, and Adam and my Abyssinian images from both sides of the
continent, these features are evident.

I think you can see what horse I am backing, however in view of the
unlikelihood of a Racquet-tailed Roller ever turning up in the Mara,
and being found in what must be croton scrub, I would really
appreciate conclusive evidence that show that this is not a RTR that
has done exactly that!

Best to all
Brian

Images under another email, as cannot attach to this thread.

On 10/11/11, Colin Beale <cb751@york.ac.uk> wrote:
> I'm interested in this - it's a lovely bird! But there's so much white
> on the forehead I can't see it immediately as anything but Abyssinian?
> What's the Racket-tailed feature I'm looking for?
>
> C
>
> On 11/10/2011 09:24, Itai Shanni wrote:
>> [Attachment(s) <#TopText> from Itai Shanni included below]
>>
>> Dear all,
>>
>> an Israeli Photographer, Eyal Bar-tov has recently came back from
>> leading a tour in Kenya where he photographed on the 14/08/2011 at 09:50
>> between Keekorok and the Mara River the attached Roller photo.
>>
>> When i saw the photo i remembered seeing strange pale looking Roller in
>> the area between Sekenani and Talek, (not far from Simba Lodge) while
>> guiding a general wildlife group back in Aug 2004. at the time i
>> dismissed it as a probable Abyssinian, but never thought about
>> Racket-tailed...
>>
>> This new bird looks very good for a Racquet-tailed Roller, though the
>> closest record for the species is about 1300 km to the south (Neil
>> please correct me if i'm wrong).
>>
>> It will be great to have more records from others who might have strange
>> looking Rollers at the Mara.
>> Itai
>>
>> Here are comments from Don, Colin and Brian:
>>
>> Hi Itai,
>> I am still on safari, but tonight on wi-fi. Your roller is absolutely
>> astounding. The bird looks small, the bill is slight, the extensive
>> white forehead and forecrown, broad white eye brow, the contrasting
>> black line from side of nape to and through eye, complete lack of
>> visible blue on wing, brown of back extending as same colour to back
>> of nape and neck, all blue underparts, I can see no reason why this is
>> not a blue form of Racquet-tailed Roller regardless of the lack of
>> racquets!
>> Exactly where was this? Are there any more images!
>> Best for now
>> Brian
>>
>>
>> Itai - a beautiful shot of a lovely bird - and as Don says, quite a
>> mystery. I wonder if any other images of the bird from different angles
>> would reveal any other features? The blue underparts certainly don't
>> resemble Lilac-breasted - far too rich. A real beaut of a bird... Would
>> be good to have it seen and photographed some more. You say you think
>> you've seen birds like this before in Mara? In the same area that this
>> bird was found? All very interesting...
>> Colin
>>
>>
>> An amazing image. I don't think there is any Lilac-breasted R. in this
>> bird. Its odd that the wings appear not to show any violet or blue. Head
>> and underparts resemble the nominate form of Racquet-tailed, but not the
>> upperparts so there is clearly a mix, but of what ?
>>
>> What date was this photo taken, and roughly where in the Mara. Any other
>> rollers nearby ?
>>
>> In the past there have been a few odd-looking Abyssinian as far south as
>> the Mara and northern Serengeti that have become lost individuals. If
>> they did hybridize with Lilac-breasted would the underparts be as rich a
>> blue as this bird ?
>>
>> Total mystery, lets hope it gets donated to science.
>> Don
>> --
>> I'd rather go birding...
>> ***************************************
>> Itai Shanni
>> Eilat & Arave Region Coordinator,
>> Israel Ornithological Centre (BirdLife partner in Israel)
>> Society for the Protection of Nature in Israel (SPNI)
>> iocitai@inter.net.il, itaisha1@yahoo.com
>> MOBILE: +972-523-689773
>> TELEFAX: +972-77-9300173
>> http://eilatbirding.blogspot.com/
>>
>> Dekel Dom 1, Beer Ora, 88810.
>> Skype: itai_shanni
>>
>> Attachment(s) from Itai Shanni
>>
>> 1 of 1 Photo(s)
>>
>> Mara Roller.jpg
>> <http://groups.yahoo.com/group/tanzaniabirds/attachments/folder/64948017/item/663448674/view>
>> Mara Roller.jpg
>> <http://groups.yahoo.com/group/tanzaniabirds/attachments/folder/64948017/item/663448674/view>
>>
>>
>
> --
>
> Dr Colin Beale
> Research Fellow
> University of York
>
> Mob. +255 (0) 684 059 123
>