Mud, Glorious Mud

Yes, I know I've pinched that title from Flanders and Swan, but I promise not to mention hippopotamuses. I've pondered this post for some years, since watching swarms of parrots coming to the wonderful Blanquillo clay lick on the banks of the Madre de Dios River in the southern Peruvian Amazonia. It was an astonishing experience, travelling before dawn by river and on foot through the forest to settle into the most commodious hide I've ever been in, and seeing the birds come in waves to eat clay from the high river banks.

Red and Green Macaws Ara chloropterus gathering on the Blanquillo wall.
(And yes, I know they've got more blue than green, but I didn't name them.)

Here we can clearly see the huge macaws chewing on the clay.
Some of these birds may have travelled up to 100km for this moment.

A small section of the sumptuous hide, which extends well to the left of this photo.
The clay banks are visible below the hide.

Southern Mealy Parrots (or Amazons) Amazona farinosa.
The 'mealy' (and the species name) means floury, and refers to the abundant dusty powder down
in the feathers, used for preening. There are also some smaller Blue-headed Parrots present - see below too.

Blue-headed Parrots Pionus menstruus and Orange-cheeked Parrots Pyrilia barrabandi.
The names enable ready identification in the photo.

So, spectacular indeed, but why do they, and many other animals, do it? It's called geophagy, and it's a topic that's occupied many good scientists (and that's not including the surprisingly large field of human geophagy, which is well beyond the remit of this blog). To cut right to the point, it seems clear that there is no one reason for the practice, and given that it's undertaken by animals as varied as primates, antelopes, tapirs and butterflies, as well as parrots and pigeons, that's hardly surprising. Chimpanzees suffering from diarrhoea were observed to eat soils containing minerals similar to those sometimes prescribed to humans with the same ailment, but this is surely not relevant to the parrots. 

It comes down to two main lines of argument, each of which often claims to be the 'right' one. One involves the selective ingestion of essential dietary minerals, and there seems little doubt that this is the basis of much dirt-eating. Termite mound soil is particularly attractive to animals from elephants and giraffes to parrots and it has been shown that the mound contains far higher levels of organic material, as well as phosphorus and potassium, than the surrounding soil. Parrots visiting sites like Blanquillo choose clays that have high sodium levels relative to surrounding soils, and much higher than their fruit diet; sodium is rapidly leached out of rainforest systems far from the sea. This need seems to peak during breeding season, when birds are stressed. However in rainforest near the sea in Central America sodium is apparently more readily available and birds seemingly don't visit clay sources.

Butterflies widely indulge in sucking nutrients from clay - indeed there's a term for it, 'mud-puddling'. With the same proboscis that they use for extracting nectar from flowers, they suck liquid from wet soil, extract sodium in particular, and excrete lots of water. Here are a few, from both Africa and South America; sadly I can't offer you names for many of them - any assistance gratefully received!

An astonishing collection, including many of family Pieridae, from along the Manu River
in Peruvian Amazonia.

The Manu River banks in fact supplied probably the most dramatic butterfly watching I've enjoyed; here are some more.

Prola Beauties Panacea prola, top and bottom views.

King Swallowtail Heraclides thoas.

Iguazu Falls, especially on the Argentinian side, was pretty good for mud-puddling butterflies too.

Broad-banded Swallowtails Heraclides astyalus (top two and nearest the camera) and others.

Common Small Lemon Eurema deva, also at Iguazu.

More massed Pierids, including Small Lemons, Iguazu.

And lastly from Iguazu, this lovely Ruby-spotted Swallowtail Heraclides anchisiades.

 Ecuador is always fabulous; here are a couple of puddlers from Yasuní National Park.

Urania Moth, Urania sp.
(And the white outline looks like a bad bit of editing, but I promise I've done nothing to the image!)

And an African offering, from the wonderful Budongo Forest in Uganda.

But, back in the Amazon monkeys also chew on clay - and they don't seek out high sodium sources.

Venezuelan Red Howler Monkeys Alouatta seniculus nibbling on clay,
while putting their prehensile tails to good use.

What's going on here? This leads us to the other strand of evidence for dirt-eating. These monkeys, and many other animals, select fine-grained clays, with no interest in their nutritional values. Plants in general would rather not be eaten, and many carry some nasty toxins in the leaves to protect themselves. Fruits are intended by the plants to be eaten, so the seeds may be carried away, but only when the seeds are mature enough to germinate. Before that, not only are the fruits not luscious and sweet, but are often actively poisonous to prevent animals from getting in too early. Anyone who's gardened however knows that birds will often eat fruit before we want to or even could. One way that many animals escape these toxins is to eat fine clays which chemically bind up the nasties, particularly various alkaloids, to prevent them being taken up by the body, and perhaps to protect the gut wall from corrosive chemicals. This seems to be a widespread practice by leaf and fruit eaters.

Recently, from the marvellous viewing deck at the lodge on the lower slopes of Mount Kenya, we watched two very different herbivores availing themselves of the mud as medication.

Female Bushbuck Tragelaphus sylvaticus unambiguously eating the dried mud.

Speckled Mousebirds Colius striatus, which swarmed over the mud, picking up lumps to swallow.
Mousebirds, a wholly African Order of just six species, eat fruit and leaves almost exclusively -
as you'd expect from the mud-eating.

However you can do more with mud than just eat it. Many large mammals in particular wallow in it as an important part of their lives. The purpose is probably a combination of cooling off, getting protection from the sun (elephants, rhinos, hippos, pigs for instance have relatively little protective body hair), removal of parasites and protection from biting insects. Secondary social factors are doubtless also important.

African Buffalo bulls Syncerus caffer, known colloquially as 'dagga boys', the dagga meaning mud.
These were enjoying the wallow in Queen Elizabeth NP, Uganda.

Part of a large group of African Bush Elephants Loxodonta africana enjoying the mud after drinking
nearby in arid Buffalo Springs NR, northern Kenya.

This venerable cow in Murchison Falls NP in Uganda didn't get down into the mud, but sprayed it liberally on her back.

Galápagos Giant Tortoises Chelonoidis nigra relaxing in the mud on Santa Cruz, one of
the few places in the generally arid archipelago where a wallow can be reliably found.

And if you have the makings and the skills, mud is an excellent building material, as humans learned long ago. Some of the best exponents of this are the wasps, especially the potter wasps in the family Vespidae, but to my surprise I don't have any photos of their work! I must rectify that, but too late for this posting I'm afraid. Birds will now have to represent this aspect of mud. Members of several quite unrelated Orders have independently evolved the very specialised skill. Here are a few.

Pacific Swallow Hirundo tahitica actively collecting pellets of mud to daub into a nest,
Kuala Penya, Sabah, Malaysian Borneo.

And the handiwork of two Australian swallows, whose nests are as distinctive as the birds themselves.
The cup of  a Welcome Swallow Hirundo neoxena, familiar over most of Australia under eaves and in outbuildings,
alongside the distinctive bottle of a Fairy Martin Petrochelidon ariel.

Australian Magpie-larks Grallina cyanoleuca (male left, female on nest, with two chicks) near Canberra.
These are monarch flycatchers (quite separate from the South American monarchs) but
quite atypical in their mud nests, which are familiar in towns and around dwellings throughout
most of mainland Australia.

Some of the most impressive mud nests however belong to two Families of birds restricted to Australia and South America respectively. However while the Australian mudnesters comprise just two species, the South American ovenbirds have over 300, though most of them don't build the eponymous mud 'oven' nests.

White-winged Choughs Corcorax melanorhamphos (chick's head at left), Canberra.
Choughs and the related Apostlebirds are among the most strongly cooperative bird breeders in the world.

Rufous Hornero Furnarius rufus at its very impressive next in the Pantanal, south-western Brazil.
In Spanish (from where the bird got its English name, so don't worry that this one speaks Portuguese!)
horno is an oven, and hornero the baker.

So, I hope this introduction to some of the things you can do with mud has been of interest, even if you're not tempted to try all of them! Thanks for wallowing along with me.

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Colours in Nature; gingery shades 3 - reptiles and invertebrates

Here is the third - and for now at least the last, though there is another in the offing - in this instalment of the occasional series on colours in nature. Starting here I've been looking at shades usually referred to as reddish-brown, rufous, copper, chestnut, rusty and other evocative appellations, looking first at some birds and more recently at mammals. 

I have more rusty birds to share with you at some stage, but I want to give the too-often ignored players, invertebrates and reptiles, a starring role before you get bored with this topic.

Given the common origins of feathers and fur in scales, it seems reasonable to assume that the same phaeomelanins that produce these earthy colours in birds and mammals are found in reptile scales, but I doubt that much work has been done on the subject. Looking at some of my pictures of Australian desert lizards, it struck me how logical it was to employ rusty tones, as they match those of the iron-infused sands and stones they often inhabit.

Central Bearded Dragon Pogona vitticeps, near Coober Pedy, South Australia.

Spotted Military Dragon Ctenophorus maculatus, near Cue, central Western Australia.

Ctenotus brooksi Kata Tjuta NP, central Australia.
This is one of dozens of members of this genus, many of them desert-dwellers.

Gidgee Skink Egernia stokesii, Whyalla Conservation Park, South Australia.
A large skink which lives in ironstone-rich rock crevices; if threatened it puffs itself up to wedge itself
into a crevice, and presents its spiny tail.

On the other hand it seems there can be a point in being a rich bronze colour even if you live in tropical rainforest.

Hitherto unidentified (ie by me!) skink, Lacy Creek Reserve near Mission Beach, north Queensland.
Any suggestions welcomed.

One Australian reptile group (of three species) actually bears the name copperhead, but ironically I've rarely seen these snakes with such an adornment. On the other hand, this very handsome Lowland Copperhead Austrelaps superbus, crossing the road in Tasmania had a lovely glossy coppery body.

Lowland Copperhead, Bruny Island, southern Tasmania.

Other snakes, of other groups, also share such tones.

Anaconda Eunectes murinus, Yasuní NP, Ecuadorian Amazonia.
This magnificent animal (whose head is just visible in the centre of the coils) was resting on floating
vegetation at the edge of a lake.

Striped Bronzeback Tree Snake Dendrelaphis caudolineatus Labuk Bay, Sabah.
This elegant colubrid (back-fanged venomous snake) is common in the region.

And so to some coppery/gingery/etc invertebrates. There are of course many, and this is just a small selection across a range of groups. It is likely that the ubiquitous phaeomelanins play a role here too, but it is also likely that different groups have come up with different pigments, as is the case with other invertebrate colours. I have chosen examples from grasshoppers, beetles, bugs, butterflies, ants, snails and millipedes. As ever, I am unable to identify most of them I'm afraid.

As with the lizards above, camouflage seems to be an important driver in the rusty tones of many Australian desert grasshoppers.

Grasshopper, Kings Canyon, central Australia.

Long-nosed Lycid Beetles, Porrostoma rhipidium Family Lycidae, Namadgi National Park,
Australian Capital Territory. This colour combination is a warning that the beetle is both toxic and unpalatable
(or so I'm told!). Other chemically-protected insects adopt the same colours to reinforce the message, and still other,
quite edible, ones do so also to gain protection by deceit.

Double Drummer Cicada Thopha saccata, Nowra, New South Wales.
It is quite possible that these colours are such an attempt at protection by mimicry; most cicadas
are avidly sought by predatory birds.

Bullant Myrmecia sp., Currarong, New South Wales.
No bluff required here - bullant stings rate very highly on scales of 'sting pain'.

Yellow Admiral Vanessa itea Mount Granya NP, Victoria; please bear in mind that I didn't name it!
I love the gradation of rich rufous tones.

Antanartia sp. (I think) Family Nymphalidae, Bwindi Impenetrable NP Uganda.
Again, subtle and rich.

This huge snail came out in the rain at Rio Silanche Reserve, north-east of Quito, Ecuador.
I don't always think of snails as colourful, but this one certainly qualified.

And to finish off, another from the Ecuador rainforests, a millipede, a group of animals I always enjoy.

Millipede, Yasuní NP, Amazonia/

I hope you've enjoyed this coppery ride as much as I have; I've come to realise that these tones are high among my favourite colours, and of course any animal is among my favourites!

As previously mentioned I have another list of gingery birds to share with you one day, but perhaps it's time to take a break from the topic and talk about something else - next time I'll be back from warm Borneo in frosty Canberra, talking to you 'live'.

BACK ON WEDNESDAY 1 JUNE

Colours in Nature: orange - invertebrates

Back from another wonderful trip to South America - you'll be seeing more on that very soon - so this offering is 'live' again. Last time, in looking at some orange reptiles and frogs, I mentioned the class of chemicals known as pterins, which were first discovered as pigments in the wings of Pierid butterflies; the best-known of these are the ubiquitious Cabbage Whites, but there are many yellow, and of course orange ones too. Since then pterins have been found in the wings of many other butterflies, as well as wasps and crustaceans, but it is highly likely that they are the basis of other orange invertebrates too. But we might as well start with some orange butterflies from various places, including right here in Canberra.

Australian Painted Lady (though this one is a male Lady!) Vanessa kershawi,
on Isotoma sp., Australian National Botanic Gardens, Canberra.

And I can't really omit a butterfly with Orange in its name, though I reckon it's stretching the definition a tad - not for the first time, as observed in my previous Orange postings.

Orange Bush-brown Mycalesis terminus, Ingham, Queensland.
Both these species are in the huge and colourful family Nymphalidae; despite the history of pterins
I can't actually find a photo of mine depicting an orange Pieridae.

I can offer orange butterflies from Africa and South America too, both of which (if my identification is correct, by no means something to be assumed) are also Nymphalids.

Cymothoe sp., Bwindi Impenetrable National Park, Uganda.
This is a genus of some 70 species restricted to the great forests of West and Central Africa.

Heliconius sp., Manu National Park, Peru.
This widespread and diverse neotropical genus advertises its unpalatability - it takes up nasty cyanides
from its food plants - with bright colours. A lot of work has been done on Mullerian Mimicry in this genus,
where many species resemble each other to reinforce the message to predators. Additionally other, perfectly palatable, butterflies also mimic Heliconius for their own protection (known as Batesian Mimicry).

Two Red Flashers Panacea prola, (with a blue friend, hitherto unidentified by me), Manu National Park.
Despite the common name, these look pretty orange to me!

Orange wasps, you may recall, have also been identified as deriving their colour from pterins. Here are a couple of examples.

Spider Wasp, Family Pompilidae, Machu Picchu, Peru.
Like the butterflies, the wings are the orange aspect here; this is not always the case however.

I assume, but do not know, that the orange legs and bodies of many other wasps are also down to pterins.

'Fire Wasp' (local name, for its ferocious sting) Urabamba, Peruvian Andes.

Potter Wasp, Family Vespidae, Kata Tjuta NP, central Australia.
She needs a lot of water to construct the characteristic mud nests.

Another spider-hunter, this time near Winton, western Queensland.

As for other orange insects, I'm not aware of work that has been done to identify the relevant pigments, but it seems likely that pterins are also involved.

Patagonian Bumblebee Bombus dahlbomii Torres Del Paine National Park, Chilean Patagonia.
This magnificent insect - the world's largest bumblebee - is at risk of extinction following the deliberate
introduction of European bumblebees, carrying parasitic protozoans which are fatal to their Patagonian
relatives, though they themselves are immune.

Chrysomelid beetle munching its way through an acacia phyllode,
Whyalla Conservation Park, South Australia.

Ladybird Coccinella transversalis, Namadgi NP near Canberra.

Harlequin Bug, Family Scutelleridae, Undara National Park, Queensland.

And lastly, moving away from the bush to the sea, pterins have been identified in orange crustaceans, presumably including this lovely crab.

Male Orange-clawed Fiddler Crab Uca coarctata, Mission Beach, Queensland.
The ludicrously enlarged claw is useless for foraging - the other, small claw does all the food gathering - and is solely
used for signalling superiority, and fighting when bluff fails.

So, that will about do us for our excursion into the orange world. Except that I should come back one day to celebrate some orange flowers - but perhaps not just yet.

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