Cape Gull/Kelp Gull

[Mark Bruce]

I posted a photo of a Cape Gull(Larus vetula) and was surprised to find that it was the first photo of this species in the Gallery.The Cape Gull was split from the Kelp Gull(Larus dominicanus) a few years back.I think that pictures in the Database/Gallery from Africa,may be of the Cape Gull and not the Kelp Gull,or have they rejoined the two Species?

Mark

[cuckooroller]

Hi Mark,
The race was described by Brooke & Cooper, 1979. I don't know if at that time they were proposing a split as I have not seen this justification. I am also ignorant of your source splitting vetula. The RSA list - Robert's - do not split this and have it as a race of dominicanus. The Sibley-Monroe (used in this Database) do not split it from dominicanus. The Clement's kind of went race-happy in one of their recent updates for dominicanus and list five (5) races: dominicanus; vetula (coastal southern Africa and Namibia); austrinus; judithae; and melisandae. Who knows what the latest SM intrepretation is for these above races as they have not pronounced themselves lately in this regard. The Howard & Moore recognizes only two races: dominicanus; and vetula (Madagascar, S Africa).

[Mark Bruce]

Hi Steve,
To my knowledge the split occured in 2002.All the post split major S.African field guides recognise this(Newman's 2002 and Sasol 2002).The new Robert's vii is due in Sept 05.I believe it will recognise the split,too.

Here's an article on the split by South Africa's Avian Demography Unit at the University of Cape Town.(The home of Robert's is UCT's Percy FitzPatrick Inst)
http://web.uct.ac.za/depts/stats/adu/species/sp312_05.htm

"The taxon of "Kelp Gull" which occurs along southern African coastline was, until recently, treated as the subspecies Larus dominicanus vetula. This taxon has now been recognized as a good species with scientific names Larus vetula. The proposed English name is Cape Gull. The iris of dominicanus is pale grey or pale yellow, whereas vetula has a dark brown iris. The taxon vetula is on average larger than dominicanus, and vetula also has a more domed skull."

Yours
Mark

[cuckooroller]

Hi Mark,
Thanks for the heads-up. I will be looking out for the justification. I wasn't even aware that a split was being considered.

[Mark Bruce]

Hi Steve,
I think you could see the justification by contacting the Niven Library at UCT's Percy FitzPatrick Institute: http://www.fitzpatrick.uct.ac.za/index.html ,the Robert's Vii Project info is also there.

Mark

[Rasmus Boegh]

The writers of the South African guides have probably been the most split-willing authors anywhere, part of it relating to various species concepts. As far as I know, the last major taxonomic review of the Kelp Gull was in 2002 by Jiguet. He argued for the recognition of 5 subspecies (as followed by Clements), mainly based on biometrics (in particular the placement/number of the tongues on the inner primaries). Why this would lead to the taxon veluta being another species is a mystery to me. I'm not saying the evidence doesn't exist, just that I - despite actively searching - have been unable to find it. The only two references I keep on getting are:

1) The Sasol fieldguide. Being a fieldguide it presents no good argumentation for the approach nor does it lead to other references that might explain it.
2) "Recent work". So, there's probably some work going on, but it apparently hasn't been published yet. Admittedly, if they already knew veluta should be recognized as a species three years ago, I do wonder why it hasn't been published yet. Of course, if I somehow have missed the publication, I'd be pleased if anyone can lead me to it. I also notice that Clements doesn't accept veluta as a species either and he seem to be the most "split-willing" author of a World Checklist. Anyway, unless Steve already has done so, I'll contact the library mentioned in the previous post and see if an argument for the split is comming or it's just another split of doubtful origin, but to the joy of many birders wishing for another tick (and yes, I'd apply for an armchair tick if it really is true - but I wouldn't go there yet). Regardless, another photo of an individual from this group is only good, especially owing to the taxonomy.

[Mark Bruce]

Hi Rasmus,

I'm sure the Niven Library,Percy FitzPatrick Institute of the University of Cape Town can help you in this regard.PFPI is the home of Robert's ,so they should be able to give you more than the S.A.guides.I'm a birder not an ornithologist.I,like most of my fellow South Africans I would tend to think ,take it in good faith when our ornithologists and institutes tell us that there has been a split.

For most South African birders there is no armchair tick to be had,it means changing their tick for a Kelp Gull to a Cape Gull,as the Kelp Gull would now be a bird that most haven't seen,or are likely to see in S.A.

Yours
Mark

[Rasmus Boegh]

Mark, yes, requiring that most birders should keep up-to-date with all the various taxonomic developments and the argumentations for them would be highly unfair and I certainly do understand why taxonomy often cause confusion (not to mention South African Larks and their taxonomy!). Anyway, I'll certainly post it here if I get a responce from the library or find an article that relate to the split. I frequently correspond with Steve - I'm sure he would post the info too in case he should get it. Unless a knowledgable person on BirdForum respond, thereby putting more light on the subject and "solve" the matter first of course. BTW, you can have one of the thousands of Kelp Gull sightings I've had in South America if I can have a single sighting of the beautiful bird in your avatar! Well, if it just was that easy...