Excuse the play on words in the title. No sane person would wade in the Chobe river. It is seething with Nile Crocodiles, some of which are ‘shudderingly’ massive. At first thought you might regard waders as a common and a somewhat boring group of birds. You could not be more wrong.
“To see a World in a Grain of Sand
And a Heaven in a Wild Flower,
Hold Infinity in the palm of your hand
And Eternity in an hour.”
― William Blake, Auguries of Innocence
Waders are ubiquitous along the Chobe river. This group includes Storks, Flamingoes, Cranes, Egrets, Spoonbills, Openbills, Sandpipers, Rails, Gallinules, Ibises, Avocets, Herons and Hamerkops. You will be astounded at the complexity in their flight, their behaviour, their different methods of hunting and how they all work together along the river. Since this post is about the Chobe river, I have excluded any discussion on seashore waders.
For starters, waders have a number of distinctive characteristics:
- Long legs: All wading birds have long legs and long agile toes.
- Long bill: Most waders have long bills and many have specialised bill shapes for specific feeding techniques.
- Long neck: Many have long, agile necks which can extend significantly when attacking prey.
- Elaborate plumage: Many develop elaborate plumes during breeding season especially Herons, Egrets and Cranes. Larger waders are conspicuously coloured while small waders usually have good camouflage.
Waders also have an number of common distinguishable behavioral traits:
- Foraging: Many waders can stand motionless for long periods while hunting waiting for prey to come within striking distance. Their attack mode is often achieved by extending their necks at high speed and stabbing their prey.
- Communities: Many waders rest at night in communal roosts and move around in mixed flocks.
- Diurnal: Most waders are diurnal, meaning they are active during the day. Some are crepuscular being most active at twilight and others like Night Herons are noctural.
- Flight: Most waders fly with their long legs extended back passed their tail feathers. Some waders with especially long necks either extend or contract their necks in flight. Herons and Egrets tend to retract their necks while Storks and Cranes extend their necks during flight. It is thought that they do this for axial balance in flight. Herons and Egrets retract their necks to achieve balance as their centre of gravity which is located at or close to the shoulder joint which articulates with the axial skeleton. Herons and Egrets are much lighter and have less body mass behind the wing. These waders are relative light-weights for such tall, long-legged birds compared to Storks and Cranes. They vary the length of their neck in flight so the mass of their heads and bill to balance the weight of their long legs and body at their centre of gravity.
“It doesn’t stop being magic just because you know how it works.”
― Terry Pratchett The wee free men
I have arranged the wader images in this post from smallest to largest birds.
Eleven Sandpipers are found in southern Africa, with seven being coastal birds and four being found mostly inland. All four inlanders are summer visitors and palearctic migrants. Of the inlanders, the Common, Curlew and Wood Sandpipers are most widely dispersed and most frequently seen. The Green Sandpiper is usually found in Zimbabwe and the eastern parts of Botswana and the Limpopo province in South Africa. The next two images are of a Common Sandpiper which has a diagnostic white pectoral region showing above its folded wing. This little bird could be mistaken for a Wood Sandpiper but it does not have a distinctive white eyebrow of the Wood Sandpiper.
The Sandpiper has a short bill for probing the mud and sand along the water’s edge. It is not a stalker and stabber like Herons and Egrets.
I am always awed by the fact that these small ( 20cm ) birds can not only fly to Europe and back but can accurately navigate that long journey each year.
“In my travels I found no answers, only wonders.”
― Marty Rubin
Of the rail family, I have only ever seen Black Crakes and Allen’s Gallinules along the Chobe River. This trip we were fortunate to see a pair of Allen’s Gallinule adults with two chicks. The adults are exquisitely coloured birds. Their camouflage from above must be excellent given their greeny-brown back and wing feathers which must blend in well in the reeds.
In nature there is a reason for everything. On the boat, we wondered what the reason was for young Gallinules having black and white striped beaks. None of us knew. The adults have large red feet which enable them to easily traverse the reeds.
Many Cattle Egrets can be found along the Chobe river feeding on insects disturbed by foraging Elephant and Buffalo or on insects attracted by Hippos. The pinky-beige feathers on its crown, neck and back are the Cattle Egret’s breeding plumage. Egrets, similar to Herons and Bitterns and even Parrots and pigeons, have specialised feathers which produce ‘powder down’. The ends of their feathers fray creating a powder which is spread during preening and is thought to improve the preening and waterproofing of the bird’s feathers.
We found a small group of Black-crowned Night-Herons down near Serondela. These birds are crepuscular and noctural so you are only likely to see them in the late afternoon when they become more active. For the rest of the day they sit in deep shade, probably sleeping. Night Herons, just like Green-backed Herons, mainly operate during the late afternoon and at night.
This Green-backed Heron was hunting from a low branch hanging over the water near Serondela. It is astounding how long they can stretch to attack their prey. They are also very wary and do not let you get too close so that 600mm lens is a necessity. The Green-backed Heron has been known to bait it prey with insects
Squacco Herons are ubiquitous along the Chobe river. They operate along the river’s shoreline, on rafts of water-lily pads and in the reeds.
These small but beautiful Herons tend to fly with their necks retracted and are mainly daytime hunters, catching small fish and insects. The Squacco, and the seldom seen Rufuous-bellied, Heron sway their heads from side to side. It has been suggested that the purpose of this swaying may be to disturb prey, as well as to adjust for the slight parallax, helping the Egret to visually localize the prey. You will also see Little Egrets doing the same thing.
One of the most striking of the small Herons is the Black Heron which was previously called the Black Egret. It has dark charcoal-grey feathers and its bright yellow feet give it the appearance of having stepped in some wet yellow road-marking paint.
What makes this bird unique apart from its stunning colouring is its hunting technique. It uses its wings as an umbrella. It is thought that fish and frogs swim into the shaded area under the umbrella formation of the wings associating the shaded area with protection.
The Little Egret is identified by its size. It is pure white and has black legs and yellow feet. It also looks like it has walked in a puddle of wet yellow road-marking paint. These are stealthy hunters which operate along the river’s edge, preying on small fish, frogs and insects.
A yellow-billed Egret flew passed us but kept a weary eye on us.
This Yellow-billed Egret was carrying a small frog its bill, an opportunity which had not gone unnoticed by a following Carmine Bee-eater.
“We can never sneer at the stars, mock the dawn, or scoff at the totality of being.”
― Abraham Joshua Heschel
You can find four types of Ibis in southern Africa, the Bald-headed, Glossy, Hadeda and Sacred ibis. All but the Sacred Ibis are commonly found in the northern and eastern regions of southern Africa. The Bald-headed Ibis is usually only found in the Kwa-Zulu Natal and Mpumalanga provinces of South Africa. Up close, the Sacred ibis looks quite prehistoric. The Ibis, and particularly the Sacred Ibis, was venerated and often mummified by Ancient Egyptians as a symbol of their god, Thoth -the God of Knowledge, Hieroglyphs and Wisdom.
This bird is usually silent unlike its Hadeda cousin, which can be politely termed raucous. It feeds on fish, frogs, small mammals, reptiles, insects and smaller birds. It also uses its bill to probe the sand and mud for invertebrates such as earthworms. During this trip I saw more frogs caught than I have ever seen on any other trip on the Chobe river. The next two images show a Sacred Ibis which had caught a large frog and was having quite a time subduing it. Eventually the Sacred Ibis managed to kill the frog and swallow it whole, head first.
The next image shows the Scared Ibis’s crop bulging with the frog it has just swallowed.
Although the Sacred Ibis is an accomplished forager, it is not adverse to a bit of stealing. Interestingly, we saw the Sacred Ibis, Little Egret and Black Heron all working in concert along the river’s edge The Black Heron was the smallest, so had to take special care to hang on to the food it found.
The Great Egret is much larger than the Yellow-billed being almost a metre in height, a third larger than the Yellow-billed Egret. Apart from their larger size, they have a much deeper gape which extends to just behind the eye and their legs are all black. Their beaks can be green in the case of a juvenile, or yellow when non-breeding but is black when breeding.
The Openbill Stork is usually only found in the northern parts of Namibia, Botswana, South Africa and Mozambique and throughout Zimbabwe. We only saw the occasional Openbill this trip but at other times the sky has been filled with thousands of these Storks – a really impressive sight. We saw no Yellow-billed Storks. The Openbills are medium sized waders characterized by their large bills, with mandibles which do not meet except at the tip. The upper mandible is straight but the lower one has an downward facing curve in it.
This stork feeds mainly on freshwater mussels and snails.
The Openbill detects the snail by sight and by touch, catching it between its mandibles. It then pushes its lower mandible’s tip into the shell, in order to remove the operculum and cut the strong muscle. Finally, it extracts the molluscs while holding the shell with the upper mandible tip against the ground.
You are likely to see Saddle-billed Storks along the river’s edge. They are usually hunting for fish, frogs and insects. This male Saddle-bill, distinguished by its black eye and yellow wattle under its chin, was disturbed by us and decided to move to a quieter place without so many ‘big clicking eyes’. The female Saddle-bill has a yellow eye ring and no yellow wattle under her chin.
I hope you enjoyed wandering along the Chobe with waders, realising there is much more to this group of birds than is commonly understood.
LESSONS FROM NATURE
I learnt from the sun
That light has to be spread,
The breeze taught me
How to be cool all the time.
The trees inspired me to be colossal in giving.
As I discovered serenity from water
And the vacuum made me understand
How to live with nothing around.
The earth taught me how to nurture
The very people who trampled it.
Fire made me realize the importance
Of being pure and yet involving.
I learnt from space the virtue of
Being BIG and yet unassuming .
For nature had all virtues a man needs to learn
In all its elements.
– Mahesh Jambunathan
Seek to understand nature, marvel at its interconnectedness and then let it be
Yet again, a wonderful (brilliant) blog.
I am in awe of your brilliance – well done my friend!
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