Unusual Cattle Egret in Nigeria
By Charlie • September 1, 2008 • 8 commentsA friend of mine, Jo Sievers, has just sent me two photos of an unusual Cattle Egret which he took near Lagos, Nigeria the day after I’d been there birding with him (more about which soon). Taken along a coastal road east of Lagos, the photos show what looks very like a Cattle Egret Bubulcus ibis with a distinctively uneven, pale blue-ish plumage, a yellow bill, and two-toned legs (pale [almost white] tibia blending into darker tarsi below the ‘knee’).
Jo saw the bird with Andy Ashford and their intitial research brought up the possibility of it being a hybrid Cattle Egret x Western Reef Heron Egretta gularis (Andy - in a subsequent discussion - has said that the bird appeared ‘gawky’ and in the field larger than a typical Cattle Egret). Both species are common along the Nigerian coast where the photos were taken, and hybridisation is infrequent but regularly suspected between various small herons (eg www.geocities.com/secaribbirds/ttmysteryegrets.html and Handbook of Avian Hybrids of the World (McCarthy 2006)).
Unusual Cattle Egret, near Lagos, Nigeria. August 31 2008. © Jo SIEVERS
Adult Cattle Egret (top) and pre-breeding adult (lower), Lagos, Nigeria.
Feb 2004. © Charlie Moores
If this bird is a hybrid it’s obviously (far) more CE than WRH: in fact if this bird was a “standard” white I’m not sure that I’d have noticed it amongst the flocks of stocky, ‘jowly’ CE (see the two photos above which were also taken in Nigeria and are of the form B. i. ibis) that are found all over Africa, Asia, and the US wherever there are cattle. However it’s not standard and neither Jo, Andy, nor I have ever seen a CE that does look like this one: so is this just an aberrantly-coloured CE, a hybrid, or is there another explanation?
I’ve tried to find as much info as I can about a) hybrid Cattle Egrets, and b) unusual plumages of Cattle Egrets (CE) and Western Reef Herons (WRH), but am at this point unsure what to make of this individual. Immature CE can apparently look greyish - but there’s no mention that I can find of them looking ‘blue-ish’. Besides, the peachy-yellow bill and what looks like the remnants of plumes on the back surely point to this being an adult. What to make of the unusually coloured legs in that case (dark in juvs, and horn in breeding adults, reddish in pre-breeding adults).
Plumage-wise this bird does look more like an intermediate form of WRH (again ‘apparently’ as I’ve never seen one) - but structurally is not right in any way for WRH, which is a typical egret and more like Snowy E. thula or Little E. garzetta). Perhaps we’re looking at melanism here?
Another photo of the same bird taken (it transpires) by Andy is online at http://www.flickr.com/photos/seth_of_rabi/2817072368/. It gives a slightly clearer view, and in particular it shows the apparently even distribution of the ‘blue-ish’ tone throughout the feather groups, and the unusual colour of the bill and the pale lores.
UPDATE: James Wolstencroft has mailed a comment which provides an alternative answer…oil droplet contamination (see below)!
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Hi Charlie,
In 1991 I had the ‘good’ fortune to work for ICBP/Birdlife in eastern Saudi Arabia directly under the great smoke plume for those apocalyptic oil fires burning in the aftermath of the first Gulf War. It was the height of spring migration and oil droplet pollution from the hydrocarbon aerosol all around us contaminated everything, and everyone, producing some quite interesting ‘colour morphs’.
Basically all pale-plumaged birds passing into the smoke clouds, or exposed to the fall-out, developed either a distinctly greyish-blue ‘cast’ or delicate blue-grey mottling! I think it likely that the Cattle Egret pictured here has been ‘exposing itself’ in the vicinity of some of Nigeria’s infamous (yet sadly most are +/- ignored) oily burning wastes. Incidentally, the burning of well-head flares in the Niger Delta is said to emit as much CO2 p.a. as the exhaust from 18 million cars. I’d bet thee are many more such birds particularly across in the delta region.
“The beast wishes it so”.
James
Hi James
Thanks for this. That makes horrible sense and I’ll bet you’re absolutely right. What an indictment of our casual approach to the environment though.
You know, I remember flying above those huge oil fires in Saudi a couple of years after I first started working with the airline - the smoke was indescribable, and the smell when we landed seemed to cling to everything. I never thought about it coating airborne migrants, but I remember the photos of shorebirds stuck in oil pools they thought were water.
(By the way, if anyone reading this hasn’t visited James’s website - http://birds.intanzania.com - can I just tell you you’re missing out on some of the best writing on the net)
Cheers
Charlie
Hi Charlie,
Look at the wellhead fire in the beginning of our documentary from the Niger Delta, Poison Fire.
Shell was kicked out from Ogoniland some eleven years ago and left their infrastructure without maintenance. Several of their wells have exploded like this in recent years. This one burned for three months.
Lars
Hi Charlie
I’ve seen some very interesting Cattle Egrets around Cape Town with a warmer-toned ‘dirty’ colouring to their feathers.
I suspect this is from feeding in mucky farmyards and similar areas — but it had me hugely confused at the beginning. Like this bird, the colouring seemed ‘all-over’ and somehow ‘intrinsic’.
Cheers
Adam
Gents,
Please compare http://www.flickr.com/photos/84677420@N00/274447822/.
Now, I’m not suggesting that our bird is a hybrid with some black heron, but notice how the hue is practically identical in the two birds; how the depth of hue varies in much the same way between the various plumage structures. Can you really put this down to coincidence? Martin Goodey has suggested melanism as a possible explanation, and if this coould lead to a distribution of pigmentation similar to that seen in black/white heron hybrids, then I’d say his idea has a lot going for it.
It’s not particularly obvious in the above photos, but the bird also has a bill of an exquisite shade of peach, and lores, eye and eye-ring are pale green.
… or is it more fun knocking the Nigerian oil industry?
What a strange looking bird - interesting to read the possible explanations!
[...] at 10,000 Birds shares photos of an Unusual Cattle Egret in Nigeria. Be sure to read this post all the way to the end to unravel the [...]
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