An odd nest for a lapwing?

While driving along a track in the grassland of the Dhikala range in Corbett NP, we spotted a pair of Red-wattled lapwings (Vanellus indicus) at a nest. They usually nest in scrapes on the ground, but I’d never seen one before. Still, the location in the middle of a track seemed oddly exposed (featured photo). The pair had chosen the grassy part where the wheels of jeeps would seldom reach, so that the danger of accidental crushing of the eggs by passing vehicles was minimized. Lapwings are known to keep guard around the nest and mob larger animals to protect their nests. I supposed that this is the way they ensure that deer or elephants do not crush their eggs (I would dearly 🙂 love to watch two lapwings trying to budge an elephant from its intended path). The very next day I saw a lapwing determinedly stand its ground in front of our jeep, forcing us to skirt it (photo below). We looked for its nest, but it must have been hidden in the grass nearby. So at least with us this behaviour succeeded.

Ground-nesting birds lose eggs to predators, and this is no exception. A count in the grounds of the Delhi zoo showed that over 40% of their eggs are taken by predators, mainly mongoose, crows and kites. It is now known that crows can discover nests by watching humans, so the extreme hands-on process of counting, as described in the article, may have caused more loss of eggs than is normal. Still, even inside Corbett NP there must be a significant number of predators on the watch for eggs. One response from the bird is camouflage: the eggs are the colour of the dust you see here, with splotches of black, which make them hard to spot among leaf litter and grass.

Like many others, I make it a principle not to go to a nest and take photos of the eggs, so that we don’t lead predators like corvids to one. But I kept worrying about the selection of such an exposed site. I later found a report of a pair nesting on the open roof of a bungalow. There was an even older report of a pair nesting between the tracks of a frequently used railroad. I wonder whether V. indicus protects its eggs by active deterrence rather than subterfuge. The very presence of two adults would alert egg-stealers of the location of a nest, even if it is hidden. So it is possible that these sightings of relatively visible nesting sites is no accident. Clearly there is much still to be understood about even such a common species of bird.

Elephant moods

Watching elephants is a pleasure. There are the tuskers, large and lonely, sometimes aggressive, but generally walking about the jungle doing his own thing. Then there are the matriarchal herds, incredibly social, but completely focused on bringing up the young. It’s a completely different social grouping than that of the apes and monkeys, but it works well enough.

The baby that you see in the featured photo caught my eye because of the grassy mud on its back. I’d not seen grass on an elephant’s back before. I looked at the others in the group. They all seemed to have it. I’m sure it helps to keep them cool, but will this innovation stick? It’ll take several visits to Dhikala range in Corbett to see the fate of this invention.

Early in the morning, a couple of days before, I’d seen a group of elephants suddenly tense. They immediately assume a protective stance around the youngest. It turned out that there was a tiger in the grass nearby. When it passed, they went back to grazing. Notice the opportunistic myna hunting the insects displaced by the elephants.

When I first came to this family group I was surprised to see a bull tusker with them. It turned out to be a chance meeting. As you can see, the group had dropped into a protective formation around the cub. In formation, they crossed the road in front of us. The bull moved away from them. Only when the bull was far enough did some signal pass between them, and the cub was allowed to move away from protection.

The bull was headed for water. We saw it move in a straight line. These lords of the jungle do not change their line of travel for any lesser creature. I watched it as it crossed the vast landscape towards a tiny pond which was invisible for us. It knew its territory very well, probably carried a map inside its head.

Once it reached the small pond in the middle of the wide open expanse, it got all the fun that it could. It drank water, squirted jets all around it, rested its trunk on its tusks, and then just lay down on the wet grass. For more than an hour I kept turning around to watch what it was doing. Eventually, as the morning got warmer it moved away.

The previous evening we’d been bullied by another tusker. We’d driven on to a path when we saw a tusker coming down it. It moved at a steady pace. There were no warning calls, no displays of threat. But the pace was relentless. The message was clear. We had to back up until a crossing, and then move to the side. In these grasslands tigers and elephants are co-equal. They give each other a a wary respect, and do not meddle.

Bee eaters

Before a mad doctor convinced a majority of my neighbours that our gardens should be saturated with pesticide, we could see many Green bee-eaters (Merops orientalis) outside our window. Now I have to travel to jungles to see this auld acquaintance. They are easy to photograph, since they like to perch in the open and keep an eye on flying prey. They make quick forays to catch a passing insect and come back to their perch.

I caught this particular one in Kanha NP, cocking its head before a flight. I’ve noticed this movement before. I think it moves its head to improve its fix on the prey just before pushing off its perch. Binocular vision has its limit for birds, because of the relatively small size of head. Moving the eye gives it better depth perception through parallax. I superposed the two separate shots to give a sense of how much head movement it makes in order to get a fix. I think it more than doubles the parallax that it would have if it didn’t do this.

Corbett NP in May turns out to be a great place for spotting several different kinds of bee eaters. I completed a checklist of three more of them. The Chestnut-headed bee-eater (Merops leschenaulti) is perhaps the second most widespread, being visible in the Terai grasslands and the lower Himalayas, both coasts of India, all through Bengal and the north-east, and eastwards through Myanmar all the way to Vietnam, south to Malayasia and, strangely, of all the islands of Indonesia, only in Java. I probably have several other photos of it from other places, but this was the only shot I have from Corbett NP.

I’ve seen the Blue-tailed bee-eater (Merops philippinus) less often, although it has a larger range: all of India south of Jammu and all of Punjab, including in Pakistan, eastwards into the Philippines and Papua New-Guinea. I remember seeing it in Kerala, Odisha, Uttarakhand, and Assam. The photo above comes from just outside Corbett NP.

The Blue-bearded bee-eater (Nyctyornis athertoni) is the least common of these, and I have only a couple of photos. The photo in the triptych above comes from Manas NP. It is visible in the Nilgiris and the two coasts around it, the jungles of Odisha and central India, and in the Terai grasslands. Further east also, its range is fairly restricted: North-east of India, and Bangladesh up to Vietnam and the north of Malayasia. Unlike the other three, perhaps it shuns gardens and tended forests. Since the last September I managed to spot all the six bee-eaters that can be seen in India. I find the Blue-bearded the most interesting of the lot, not only because it is less common, but also because it is the only bee-eater seen in India which is not in the genus Merops.

Dandies

Harsh cries ring through the jungles of central India in summer: the call of the peacock. I normally ignore the Indian peafowl (Pavo cristatus). They are commoner than crows and pigeons when you enter the open jungles of this region. But as the monsoon’s breeding season approaches I keep a watch for the mating display of the male. If you are lucky enough, you can get a photo that is worth the halt. Sometimes you see a lek: a group of males all displaying together, for the benefit of a seemingly uninterested female. This is perhaps its core behaviour. The female selects a mate based on the size and colour of the train. Growing a large train takes energy, in terms of health and food, and the ability to escape predators. There’s no faking it. At the same time, the female’s preferences selects the biggest trains, and therefore the offspring are likelier to have big trains. Repeated for generations this pushes the species into the direction of males with more spectacular trains. Since the genus could be recognized in 18 or 19 million years old fossils, most species in the genus have evolved towards bigger trains.

Unfortunately the only peacock I’ve seen is Pavo cristatus, the Indian peafowl. Native to Bangladesh, India, Nepal, Pakistan, and Sri Lanka, breeding populations have been introduced in Singapore, Taipei, the UK, and the USA, largely in Florida. I’ve yet to see its larger cousin, the Green peafowl (Pavo muticus). It is disappearing fast in Myanmar, but I suppose on a trip to Thailand, Vietnam, or Cambodia, or even in the extreme east of India, I could plan to visit its habitats. It is a little astounding that viable hybridization between P. cristatus and P. muticus can be established. It seems that the reason is that in birds cellular evolution is slow, and two species like this, which have separated only three million years ago have not changed sufficiently for their crosses to be unviable. I wonder whether anyone has tried crossing the Congo peafowl (Afropavo congensis) with either of the Pavo.

An interesting thing about the feathers is that they never fade. That is a clue that the colours are not due to pigments; pigments would oxidize over the years and change. The iridescent colours are due to, well, iridescent diffraction of light. Microstructures in the feathers produce the specific wavelengths that are seen, and a little change in the shape and size is enough to change colour. I’m surprised that a comparative study of the feathers of the peafowls has not been done. It seems that feathers don’t fossilize well, otherwise it would have been possible to examine the feathers of the extinct European peafowl (Pavo bravardi in the south and Pavo aesculapi in the north) and tell their colours. It is strsnge that so little is known about birds as spectacular as these.

Changeable lizard wears red

Noticing a changeable lizard (Calotes versicolor, also Indian garden lizard) sunning itself on a fallen trunk of a tree, I stopped the jeep. In these hottest days of summer, everyone is constantly following the weather, watching for the arrival of monsoon. Today we look at satellite pictures, but once the changing colour of this lizard told people about the coming rains. Monsoon is its breeding season, and just before it the males change from their dusky olive or brown to this bright form, with the bright red head and black patch on the throat. I’m always surprised by how large the males are: more than 30 cms in length, with that wonderfully long fourth digit on its rear legs. We saw this one in Corbett NP, in the Terai grassland.

The very next week I saw another near Kanha NP, in the central Indian jungle. Notice the difference in the ground colour, with the dark stripes on one. The shapes of their heads and jaws also seem to be somewhat different. Growing up on the Gangetic plains, I would see both varieties in gardens. I was a little confused by these differences. Were they the same animal? Eventually I decided to treat them as the same. But it turns out that the “species” hides multiple species across its range from Pakistan to south-east Asia, which are just beginning to be enumerated. Different subspecies began to be enumerated in the 1990s, but now genetics seems to establish three different species in Myanmar and four in India (with some overlap in their ranges). It also turned out that the “type specimen” which used to be held in Paris had been misplaced. So a new “type specimen” was collected and described in 2016, but, because of the loss of the original specimen, it may not yet fully accepted as an example of Calotes versicolor. It seems possible that the name C. versicolor applies only to the second photo, whereas the header photo could be of the newly identified species Calotes vultuosus.There are mysteries peering at you from your garden!

The threatened Jackal

We were watching birds in the Bijrani range of Corbett NP when I saw a sleek shape lope past on a parallel path. Our driver-guide was quicker than me, and immediately backed our jeep at speed. “Don’t worry, you’ll get a good photo,” he told me as I tried to focus through the bumps. Golden jackals (Canis aureus) like to travel on human roads, their adaptability is part of their tragedy. They are still seen as not needing the helping hand that we hold out to tigers and leopards, although they are disappearing faster. Our guide was right. The jackal turned with the road it was on, and came to a halt at the junction with the road we’d taken, just perfectly positioned for a close shot. It decided that we were a threat, and abruptly changed direction to backtrack. But there was another jeep ahead of us, so it came back, crossed the road, and disappeared into the growth next to it. I got a few good shots. The afternoon light was terrific, and these were about the best shots of jackals that I’ve ever got. The best of the driver-guides whom I’ve met in national parks in India know animal behaviour inside out. It is a pleasure to be with them.

Don’t you find yourself with some sympathy for underdogs? The beautiful Golden jackals are the underdogs of Indian wildlife, and they need all of our sympathy. Not as charismatic as the tigers or even leopards, not as impressive as the elephants and rhinos, they are slipping through the safety net of public sympathy towards extinction. The invention of key conservation species like the giant panda and the tiger was supposed to buy forest workers some breathing space, as they regenerated the habitats around the advertised species and made it safe for other, less saleable, creatures. Unfortunately, stardom has skewed these projects, and they are now geared towards the big few rather than the whole biosphere. As a result, the jackals of this world continue to suffer threats.

Clever little mynas

One morning in Corbett NP I was watching a herd of elephants walk through tall grass and noticed that a flock of common mynas (Acridotheres tristis) followed them. Sometimes they sat on the elephants, hitching rides on their back, ears, tusks, and even, once, on a trunk. At other times they swooped and swerved between the bulky herbivores. I’d seen them in association with other large herbivores before: gaur (Bos gaurus, the Indian bison), Indian one-horned rhinoceros (Rhinoceros unicornis), nilgai (Boselaphus tragocamelus), and even sambar (Rusa unicolor). I knew something about what they were doing: rendering a service to the host by picking ticks off them, and also keeping an eye on the many insects thrown up from vegetation by the passing of these large animals. This mutually advantageous behaviour is unlikely to be genetically programmed, partly because the birds seem to be able to generalize from one large herbivore to another. In every jungle, the mynas find more than one large herbivore which provides the same opportunity for mutual benefit. If humans did something like that, we would call it cultural learning.

Later that day when I saw a sambar (Rusa unicolor) in the distance with a myna on its back, I didn’t think much more about it. But now, looking at the photo I realize that it was a jungle myna (Acridotheres fuscus), easily told from the common by the tuft of feathers that it has over its beak. So this mutualism between herbivores and birds is deeper. In Africa I’d seen oxpeckers (genus Buphagus) riding on herbivores; it is still an open question whether there is an element of parasitism in this relationship. Oxpeckers are not in the same family as mynas, but may be closely related. So this mutualistic behaviour between some mammals and dinosaurs could have evolved earlier, and the culture could have passed on even though the species evolved into new ones. This may seem weird, but then humans may have inherited the culture of using hearth fires from ancient ancestors called Homo erectus. I wonder whether there are other examples of cultures being preserved for times long enough for biological evolution to disperse it across multiple species. For example, was the use of tools a discovery made so far back in our ancestry that both chimpanzees and humans took the idea from a common ancestor?

Which hawk-eagle?

One species that I find most confusing in the field is the Changeable hawk-eagle (Nisaetus cirrhatus). The least confusing aspect is that there are two morphs. The one you see in these photos is called the light morph. The dark morph does not have the streaked white chest, and is much darker uniformly. But more than that, the field identification is rendered more confusing because of controversies about subspecies and cryptic species. This has left a legacy of birders looking at multiple characteristics and distinguishing between features which could perhaps be widely variable without distinguishing species or subspecies. I will not enter that controversy (you can read a condensed version in its Wikipedia article) but will go with the Linnaean wisdom: if two things have the same binomial, they are one species.

It’s a common enough bird, easily spotted across India, south of Jammu, below the Tibetan plateau, and eastward across Asia right up to Banda Sea, in central and South Vietnam and the Philippines. What was uncommon about this sighting in Kanha NP was that I found it in a little muddy pool drinking water in great gulps. It looked up as we stopped, but after that it didn’t pay us much attention. It is the apex predator in its own niche, after all. I’d never seen it drinking water before, so I didn’t know whether it was extra thirsty because of the heat or what looked like an orgy of drinking was normal. But then, just a week before, I’d seen a small but feisty Jungle owlet (Glaucidium radiatum) drive one away by flying directly at it. I wouldn’t have thought that was normal either, except that a much more experienced birder said that he’d seen smaller raptors shooing away bigger ones before. The longer you watch birds, the more interesting behaviour you see. I suppose all that it means is that, within their physical limits, creatures have more autonomy and adaptability than they were once supposed to have. Hawk-eagle, thy name is change.

The shapers of jungles

Kanha is one of the most beautiful national parks. The first thing you notice are the enormous sal trees (Shorea robusta) forming patches with closed canopies. Then you notice that they are actually stands of trees in a larger grassland. The stands are carpeted with fallen leaves. The sunny grasslands are full of herds of chital (Axis axis, spotted deer). At the edges between the open grasslands and the forest are the more cautious sambar (Rusa unicolor) and barasingha (Rucervus duvaucelii, swamp deer). But if you look closer you see the species that shapes the landscape by removing litter and tilling the ground: termites. Some are visible by their mounds dotted throughout the forest, others hide in living trees and dead logs.

I spent quite a bit of time trying to figure out how high the termite mounds were. It sounds silly, but then I was in a jeep which spent three days rushing through the forest in search of tigers. Most tourists holiday in nearby resorts, and spend their times in swimming pools and air-conditioned rooms, making a couple of forays into the jungle. Of those who come to the forest, most are interested in tigers. So tigers are a boon to the locals who make their living on tourism, and their behaviour is geared to such people. A very few visitors come to the forest to see more, and the guides and jeep drivers are happy to talk to them about their own experiences. But you just cannot get off jeeps to make measurements. So I had to improvise by taking photos of termite mounds with different things to give a scale. Everything simplified when I saw two people, forest workers, walking between two mounds. That photo clearly told me that the large mounds were about two meters high. I saw the Northern plains gray langur (Semnopithecus entellus, hanuman) crouched behind a smaller mound. These langurs are about a meter tall. So that sort of verifies my estimate by eye that the larger mounds are twice as tall.

I’ve found termites (order Blattodea, infraorder Isoptera) fascinating for a while. They are cockroaches (order Blattodea) which adapted to eating wood by harbouring a microbiome of bacteria, protists, and fungi in their stomach. In fact, the study of termites gave the first clue that many animals could have flourishing ecosystems inside them, a discovery that is now increasingly used in treating human disorders like Type II diabetes. In a forest they munch up fallen logs and leaves and are important recyclers. But they bore into trees and wood, which makes them pests for us at home or in farms. This bunch of cockroaches also developed eusocial behaviour some time in the Triassic or Jurassic, becoming differentiated into castes of workers, queens, and kings. When I was young I would see yearly swarming of termites, as a queen and her retinue set off from their old palace in search of a new home. So I know that a termite is only a couple of millimeters in size. The mound is a thousand times larger. Calling it a palace is shortchanging the mound, because I know of no human queen who lives in a two-kilometer tall palace. Perhaps one should compare it to a medieval citadel, a city which houses the court and also all the industry which supports it.

I’d spent some time photographing termite mounds up close in the Bijrani range of Corbett NP. You can see from these photos that they have a contoured surface which is rather smooth. The material glitters in the sun, which makes me think that bits of minerals in the soil, or insect chitin could be incorporated into it. I found an interesting group of papers which studied the strength and engineering of these mounds in a non-destructive way. They found that two castes of termite workers continually build pellets of wet mud. Other castes of workers then cement these “bricks” into walls using liquids that they secrete from the body. The wetness of the mud allows the suspended granules of mud to settle into any cracks in the walls that need repair, and the termite-spit then makes it proof against the hard monsoon of this part of India. Another paper led me to believe that the two meter tall termite citadels could be several hundred years old.

But which termite made these mounds? I’m as sure as I can be, without a photo of a termite, that they are made by Odontotermes obesus. I wish this common forest termite in had an easier name. This is the species which builds these tall conical mounds with flutes which look like Gaudi could have dreamt them up. But I’d seen and photographed other shapes too. Not knowing enough about termites, I’d assumed that they were merely citadels in the early stages of construction. But apparently not. Very often, the shape of a mound tells you with certainty which species built it. But Chhotani, in his 45 year old gem of a paper on the termites of Kanha NP tells us of multiple species which can be found in the mounds and fungus gardens of O. obesus. And more interestingly, he describes four different shapes of mounds, all of which seem to be built by O. obesus. With this observation he speculates that when there are more detailed studies one would find that what we call a single species now will be resolved into multiple species, each one building a mound of a given shape. Unfortunately, the study of termites in India is in its infancy. Even a paper from five years ago, which claims that there are 286 species of termites in India, making up 10% of the world’s termite biodiversity, added six new species. I was not surprised that no one has performed a gene profile of O. obesus from Kanha to check Chhotani’s conjecture. So we don’t yet know whether we can really tell the species of a termite from the shape of its mound. There are so many angles to termite life, so many loose ends in their story, that one really has to look at several pictures to piece them into one view of these shapers of jungle landscapes.

Chital

We crossed the last river bed on the way back from Bijrani range in Corbett. This was goodbye. We stopped to see a Woolly-necked stork (Ciconia episcopus), our last addition to the trip’s list of birds. A family of chital (Axis axis) was grazing between the pebbles at the bottom of the stream. A healthy buck (the featured photo), a doe, and two fawns (photo below) ranged slowly over the stones, picking delicately at small shoots. Strange that they would venture here for such slim picking; they must find these leaves delicious.

Chital lie in a genus of their own, Axis, the last remnants of a five million years old twig on the tree of life. Fossil Axis are found from Iran eastwards to Southeast Asia. They are most closely related to the Barasingha (Rucervus duvaucelii, the swamp deer). Once these were common in the Dhikala range, north of this river. But when its homeland was inundated in the 1960s by the floodwaters gathered behind a dam in the neighbourhood, they went locally extinct. The Chital are now only found in India; a landscape with wild chital tells you definitely that it was taken in India. When they become extinct, a five million year old story will come to an end.

Science da kamaal! Posts appear automatically while I travel off net.

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