Hi friends,
I have been surprised to see that some authorities, including worldbirdnames, have accepted the split of the Eastern Cattle Egret from the taxon found in the rest of the world. Given the way that Cattle Egrets have spread so widely around the world in such a relatively short time, I find it hard to believe that gene flow could have been interrupted long enoguh for a new species to emerge.
I would welcome any thoughts.
Dr John Penhallurick
86 Bingley Cres
Fraser A.C.T. 2615
Australia
email:jpenhall@bigpond.net.au
Phone: Home (612) 62585428
Mobile:0408585426
sunt lacrimae rerum et mentem mortalia tangunt Aeneid Book 1,line 462 “The world is a world of tears, and the burdens of mortality touch the heart.”
Magna est veritas et praevilabit Vulgate, Book of Edras
Si vis pacem para bellum Publius Flavius Vegetius Renatus http://en.wikipedia.org/wiki/Publius_Flavius_Vegetius_Renatus ‘s De Re http://en.wikipedia.org/wiki/De_Re_Militari Militari, book 3
Please visit my website:http://www.worldbirdinfo.net
Please also visit my blog at http://jpenhall.wordpress.com/2011/04/02/proof-that-there-is-not-a-scrap-of- evidence-in-favour-of-the-ipccs-attack-on-carbon-dioxide/
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Hi John, The situation with the Barn Owls is different. Several measures, including within-group genetic distances versus the between-group distances, justify the recognition of 3 species. Barn Owls are resident. But the Cattle Egrets seem to be widely dispersive. Thus there is no valid comparison between the two sets.
Dr John Penhallurick 86 Bingley Cres Fraser A.C.T. 2615 Australia email:jpenhall@bigpond.net.au Phone: Home (612) 62585428 Mobile:0408585426 sunt lacrimae rerum et mentem mortalia tangunt Aeneid Book 1,line 462 “The world is a world of tears, and the burdens of mortality touch the heart.” Magna est veritas et praevilabit Vulgate, Book of Edras Si vis pacem para bellum Publius Flavius Vegetius Renatus’s De Re Militari, book 3 Please visit my website:http://www.worldbirdinfo.net Please also visit my blog at http://jpenhall.wordpress.com/2011/04/02/proof-that-there-is-not-a-scrap-of- evidence-in-favour-of-the-ipccs-attack-on-carbon-dioxide/
According to C and B, Payne and Risley (1976) first suggested that the two should be split based on breeding plumage differences. Cytochrome-b sequence distances (McCracken and Sheldon 2002) are more consistent with keeping them as subspecies. The issue of whether they are species or ssp has been bouncing around for a while, but this isn’t where the original conversation started by John P in relation to mixing of the two taxon. I am very keen to see photos of evidence the two forms are mixing because I having found any yet, maybe Bharat’s forthcoming paper in Dutch Birding will address exactly this issue.
Cheers Jeff.
G’day John,
I think we are discussing different things here, I have been responding to the premise of the very recent expansion of Cattle Egret into Australia and America as evidence that the same must be ongoing/happening within the core of the Cattle Egret population in Africa and Asia, thus a single mixed population. I thought you must have been suggesting that Barn Owl was mixing similarly as a result of recent distribution changes, I apologize. Just for the record I am currently working on a book for which we have Cattle Egrets in Australia listed as a subspecies as per C and B and it will remain that way until further work demonstrates otherwise. This is based on DNA, but the fact remains that although capable a covering vast distances as John P discusses in his opening email the two subspecies remain discrete and identifiable, it’s a very intriguing situation.
Cheers Jeff.
I didn’t say they had arrived in Australia and the American recently as a result of the stocking of the land. I implied they had spread worldwide relatively recently.
John Leonard
seychellarum is said to be intermediate between ibis and coromandus, though I can’t confirm that personally
David James, Sydney burunglaut07@yahoo.com ==============================
Cc: ‘Birding-aus’ Sent: Tuesday, 30 August 2011 6:30 PM
G’day John,
If you have a look at photos of both taxon in breeding plumage you will see substantial difference in extent of coloured feathering to the head. They appear to have been separated for a long time and continue to be. It’s and African Asian divide which has persisted despite the invasion east into Australia and west to the Americas. If they are invading each other as you suggest then I would expect the plumage differences to not be sustained and intermediates to be obvious which they are not.
Cheers Jeff.
From memory I think the first suggestion of a potential split was in McAllan & Bruce (late 1980s) checklist of the birds of the state of NSW in Australia, which was privately published. My copy is in storage so I can’t check right now. I think it was based on differences in bare parts colours in breeding plumage and a gap in the range in the Middle East, but not a full taxonomic study. I think Sibley & Monroe may have followed McAllan & Bruce, as they tended to adopt almost any published split. From there it has gradually gained support and “legitimacy” but has not been studied rigorously. Many splits are based on similar histories of minimal taxonomic assessment. Some are probably good, but many are bad decisions and all are poor process. It’s only really different definitions of species, the two refs I mentioned both recognised “allospecies”. Cheers
David James, Sydney burunglaut07@yahoo.com ==============================
Cc: ‘Birding-aus’ Sent: Tuesday, 30 August 2011 5:47 PM
Dear Dr John Penhallurick, I agree with you, I also don’t think that it could be a separate species ! I hope they have done detailed research when they accept it !
Best wishesDr. Bharat Jethva
Hi David
There will be a paper published by R Ahmed on the identification and status of the three cattle egret taxa in the next Dutch Birding (33 nr 5; sent to subscribers within a month).
All the best
Arnoud van den Berg
PS: It may be noteworthy that the Dutch taxonomic committee (CSNA), which follows PSC and therefore is considered as ‘progressive in splitting’, did not give species status to B. i. coromandus, as it did not share the views on supposed diagnostic features presented in ‘the Ripley guide 1&2 (2005)’.
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G’day Bharat,
Whether or not they are species or subspecies is in itself a separate discussion to whether there are two discrete identifiable populations or a single mixed up one which was the starting point established by John. Whether ssp or species they remain discrete and have done so long enough to present with plumage differences which don’t appear to cline so they can’t be freely intermixing between Africa and Asia. Establishing in America and Australia is clear evidence the two populations are capable of traversing such distances but the two plumage types are sustained so they aren’t freely mixing across the Middle East for what ever reason.
Cheers Jeff.
G’day Dave,
I have a single image of a Cattle Egret from the Seychelles and the plumage is straight out African, one photo isn’t definitive evidence however.
Cheers Jeff.
Sent: Tuesday, 30 August 2011 6:39 PM Cc: ‘Birding-aus’
seychellarum is said to be intermediate between ibis and coromandus, though I can’t confirm that personally
David James, Sydney burunglaut07@yahoo.com ==============================
orientalbirding@yahoogroups.com Cc: ‘Birding-aus’ Sent: Tuesday, 30 August 2011 6:30 PM
G’day John,
If you have a look at photos of both taxon in breeding plumage you will see substantial difference in extent of coloured feathering to the head. They appear to have been separated for a long time and continue to be. It’s and African Asian divide which has persisted despite the invasion east into Australia and west to the Americas. If they are invading each other as you suggest then I would expect the plumage differences to not be sustained and intermediates to be obvious which they are not.
Cheers Jeff.
No the same argument can’t be applied John,
Barn Owls didn’t arrive in Australia and the Americas recently as a result of the stocking of the land, they were already there and have established plumage differences as well.
Cheers Jeff.
G’day John,
If you have a look at photos of both taxon in breeding plumage you will see substantial difference in extent of coloured feathering to the head. They appear to have been separated for a long time and continue to be. It’s and African Asian divide which has persisted despite the invasion east into Australia and west to the Americas. If they are invading each other as you suggest then I would expect the plumage differences to not be sustained and intermediates to be obvious which they are not.
Cheers Jeff.
Dear Dr John Penhallurick, I agree with you, I also don’t think that it could be a separate species ! I hope they have done detailed research when they accept it !
Best wishesDr. Bharat Jethva
The same argument could be used against splitting the Barn Owl into Eastern and Western.
John Leonard