Mudskipper

Two branches of life grabbed the Devonian opportunity to colonize a new environment: the land. The fastest evolving were the tracheophytes, a group of plants which developed internal plumbing to transport water and nutrients, and rapidly spread across the continents, growing into new ecosystems of massive forests which captured atmospheric carbon and buried them deep underground. Once a land ecosystem developed, the second group, our remote ancestors crawled out into it to eventually find the buried carbon and release it back into the air. But this is not the story that fascinates me today. It is the story of the remainers, our cousins in nerve and bone, the fish, that I find gripping. Over the eons that passed, they evolved more exquisitely into new opportunities in the main element of our planet: the water.

I have seen mudskippers now and then, mostly in the muddy mangrove forests of the east coast, a littoral of the world’s center of biodiversity, namely the Indo-Australian seas. A year ago, when I visited Jamnagar I realized that I was in an unique place. The special shape of the Gulf of Cambay causes enormous tides, and creates an unique ecosystem: a huge expanse of tidal mud flats, and a second hot spot for mudskipper diversity. I watched one flopping in the exposed mud at low tide. Its fins were placed far ahead on its body, very close to the head. As I watched it walked on its fins from one shallow pool of water to another. Which species was it? I am not an expert on identification. But from its shape and the stripes on its body, my guess is that it was the Boleophthalmus dussumieri, common across east and west coasts of India all the way to the Arabian gulf.

The bulge behind its head came from a bubble of water it holds to keep its gills moist, as it breathes through its skin and the mucous membrane that lines its mouth. The one I concentrated on had its mouth closed, but the others kept opening their mouths to breathe. The males create burrows in the mud where females lays eggs. In high tide the burrows fill with bubbles of trapped air where they retreat to hide from aquatic predators. One mystery which has received a lot of scientific attention is how they survive in such low oxygen content. The other mystery dawned on me slowly as my companions left me to go watch the numerous birds which stalked the flats. Why do they not feed on these exposed mudskipper? They are eaten by the fishermen of Gujarat. Are they toxic to birds?

Why do I find the story of mudskippers so gripping? Its because I was wrong about them; they are not remnants of the ancient group of fish which flopped on to land and gave rise to tetrapods. They are part of most recently evolved group of fishes: the percomorpha (coloured in the evolutionary tree shown above), and are more recent arrivals on earth than the mammals. Mudskippers are close cousins to seahorses and mackerel and eels, and the many other percomorphs in modern seas. Mudskippers (Gobioidei) began to evolve along the western coasts of the giant ocean called the Tethys, just as the first mangroves were beginning to colonize tidal mud flats, and Gondwanaland was breaking up into Africa, Australia and India. That is a remarkably elegant and parsimonious explanation of the present global distribution of mudskippers. What a wonderful solution to that mystery.

Green thoughts

Newspapers have written a lot about tremendous drops in insect populations and their imminent extinction. With the climate changing before our eyes, mountain ecosystems moving to higher altitudes, the Arctic losing its ice cover, this was very clearly part of a vast and immediate problem. Or so I thought until I saw a headline which said: Insects are declining in India and we don’t even have data. Umm, if we don’t have data, how do we know? It was time to do a web search. The results were not exactly reassuring, but not harbingers of doom either.

Insect populations are definitely declining worldwide, and extremely rapidly in some places. But, as an article in The Atlantic said “The claim that insects will all be annihilated within the century is absurd … Indeed, insects of some sort are likely to be the last ones standing.” Last year the journal Insect Conservation and Diversity put together a special issue on the topic of rapid decline of insects, where many of the articles pointed out that declines have been seen in several insect species, but increase was clear in others. Climate change and direct human intervention upsets all kinds of balances in nature. An article (pay walled, unfortunately) set out a further program for study, opening with the sentences “Many insect species are under threat from the anthropogenic drivers of global change. There have been numerous well‐documented examples of insect population declines and extinctions in the scientific literature, but recent weaker studies making extreme claims of a global crisis have drawn widespread media coverage and brought unprecedented public attention. This spotlight might be a double‐edged sword if the veracity of alarmist insect decline statements do not stand up to close scrutiny.

So I am reassured that I can continue to worry about the numbers of green jewel bugs (Chrysocorix stolii) as I photograph them.

On a clearer day

A couple of warmer days cleared the haze a little. I can now see a smudge above the trees which is the horizon. With the relatively mild amount of pollution the sunrises and sunsets are glorious. I sipped my second cup of tea and looked at the enchanting yellow morning light on the mango tree. The tree is still in bloom, but if you look at the inflorescence carefully, you can already see the green spheres which are the new fruit. A year has rolled around. Last year this time everyone was busy not paying attention to dark clouds. This year everyone is looking at that little bright patch in the clouds, the vaccine, and telling each other that the storm is over.

But one can still make the best of the day. The Family breezed in and announced excitedly “Grey hornbills.” As I searched for my spectacles, she impatiently handed me my camera, knowing that it would be the next thing I would look for. There they were, on a gulmohar tree far away. Indian grey hornbill (Ocycoros birostris). Two of them. Probably juveniles, judging by the orange coloured bare skin around the eyes, and the incompletely developed horn above the bill, the casque. So the nesting pair which had lost its usual nesting hole when last year’s storm blew down the tree did manage to find another tree in the garden.

This pair afforded us a good view of what hornbills do when they are not building nests or looking for food. One sat and preened its chest feathers, the other scratched behind its ears with one claw. They looked content. I watched for a while, clicked off a couple of dozen action photos of birds doing self-care, and wandered off. Half an hour later, when I came back, they had gone. I guess the young eventually leave the vicinity, find a mate and a nesting site, and settle down to produce brood year after year. Our garden has had a single breeding pair for year. The young do not seem to come back here to nest. Perhaps that is for the best. Since they can survive in trees that humans grow in gardens and cities, they will keep finding new nesting spots. At least one of this group of magnificent large birds has thrived in an urbanized world.

Egrets, regrets

When a cattle egret (Bubulcus ibis) flew up to sat on a tree at dawn, I had to take out my camera to take some photos. After having spent some time in my initial years of watching birds, I’ve given up looking at these white egrets. They are very common, and since the four species are not terribly easy to tell apart, I don’t usually bother to either record them or to look hard. Cattle egrets are the easiest to tell apart from the others; they always have some yellow on them. In the breeding season it covers their head, neck, and back. In winter, the yellow recedes to a small patch on its forehead, as you see in the photo above.

To identify the other white egrets you have to look at the feet and beaks. Since the birds are usually seen in extremely muddy places, this is not easy. The little egret (Egretta garzetta) has a dark beak, dark legs, and yellow feet. In breeding season it has two long plumes hanging behind its nape. The large egret (Casmerodius alba, formerly Ardea alba) has dark legs and feet. Its beak is dark in the breeding season, and yellow otherwise. In both seasons it has a dark line extending from the beak under its eyes and beyond. This is called the gape line. If you see it flex its somewhat longer neck, you might see a kink in the neck. In the photo above (taken last February near Jamnagar), the gape line clearly extends beyond the eye, and there is a definite S-shaped kink in the neck, both telling us that this is a large egret. The intermediate egret (Mesophoyx intermedia, formerly Ardea intermedia) is the most confusing. Its legs, feet, and beak are very similar to that of the large egret, but the gape line stops below the eye. Also, its neck is a little shorter, and does not kink into an S-shape. Distinguishing them is always a puzzle, and I’m never sure that it worth taking the time to solve.

Against the light

The warm mid-morning sunlight and the cool air of the garden made me lazy. There were butterflies fluttering around the edges of the lawn, but I did not want to get up to photograph them. “I have a monster zoom,” I told myself, “let me use it.” Easier said than done. These marvelously bright and colourful creatures can disappear into the background when they want to. I saw a common pierrot (Castalius rosimon) flying around a tree, but every time it sat down I would lose sight of it. Eventually I managed to figure out where it was going back to sit each time, and focused on those leaves. After I got the photos (one is featured) I realized that it was disappearing into the bright light reflected from the surface of the leaf. The bright patterns on its wing broke up its outline very effectively, exactly like the camouflaging stripes on a tiger’s skin. You cannot imagine a tiger being unspottable when you see it in photos, but when you are trying to spot one in the dappled sunlight of the jungle it is very hard to see. The common pierrot is similar.

I’ve usually been extremely lucky with the lemon pansy (Junonia lemonias). I’ve often caught this butterfly with its beautiful black and white spots on tan forewings, the four eye spots bright, sitting with its wings stretched out on a sunny leaf. This time it was fluttering around a hedge, coming down in the open and suddenly vanishing. I followed it with my eyes for a while, and then looked through the camera. The camouflage was incredible. It would disappear on the open lawn. As it came to rest on blades of grass, the pattern would fool the eye into seeing it as little bits and pieces of brown earth. The eye spots serve a different purpose: distraction. When a predator, such as a bird pounces on it, it can be fooled into thinking that these spots are eyes, and bite at that part of the wing. You may have seen butterflies without part of their wings. That’s often due to birds misjudging where to strike. Losing a portion of the hind-wing does slow down a butterfly, but it can still manage a slightly slower flight. Laziness taught me something that morning!

A musical garden

You don’t need to look up from your work to know that there are purple sunbirds (Cinnyris asiaticus) around you. Their sound fills a garden. The Family spent a while trying to look for them, but it was useless. The males are small, dark, and have a handsome song. The females are drab and brown, but easier to photograph. Waiting pays off. After a day I saw two of them screaming songs at each other from the open. The dark plumage makes them one of the hardest of birds to take a good photo of, but I think the silhouettes you see here are reasonably interesting.

I’ve written about them before, and given you their songs, so I won’t do that again. I will just leave you to imagine the sunlit patch of garden, surrounded by tall trees, where these birds flit from branch to branch. Through the trees you can see the distant Kalsubai hills, and below that the enormous lake behind the Bhandardara dam. A restful place to work from.

A champion

My only sighting of a Himalayan Birdwing (Troides aeacus) came one evening in the Mizo hills area of Tripura. A very large black and yellow butterfly flew past overhead, headed straight for flowers at the top of a nearby tree. I took a couple of photos, but it was sitting edge on to me, and in silhouette I could no longer see the attractive colours. We talked about the then record-holder amongst Indian butterflies, the Southern Birdwing (Troides Minos), of which one specimen collected in 1932 had a wingspan of 190 mm (7.5 inches). I’d not seen one then, and I still haven’t. The butterfly we had just seen was easily as large as a sparrow, perhaps larger. But the photo was not very good, and I put it away.

This March a new champion emerged. One specimen of the Himalayan Birdwing turned out have a wingspan of 194 mm, beating its southern cousin by a whisker! When I read that paper, by Shristee Panthee and Peter Smetacek in Bionotes (Bhimtal), I had to dig out the featured photo. It is not a good photo at all, but if you look carefully, you can see that the hindwing is yellow and the forewing is black, with some streaks of white or yellow. When you have only one photo of a champ you are proud of it, even if he is not seen at his best.

Golden langurs

Gee’s golden langur (Trachypithecus geei, or just the golden langur) is the rarest of monkeys. Scattered reports of it were found in literature since the 19th century CE, but the first specimens were captured, and a description published only in 1956. Three of us, The Family, our friend and first wildlife guide, Doe, and I, had a completely unexpected view of a small group in Trishna Wildlife Sanctuary in Tripura.

We’d reached the sanctuary late, walked for a bit into the forest, and given up hopes of seeing anything. Doe and The Family stood at the edge of the pond and chatted while I walked down a spit of mud to take photos of dragonflies. There was a bunch of about ten monkeys making a commotion overhead. Finishing my shoot I looked up, and found that they were pretty unusual monkeys. There are two populations of the golden langur, separated by about three hundred kilometers. One is in Tripura where we had our sighting, but the better known one is in Assam, north of the Brahmaputra, into south-east Bhutan.

The group was a little shy in the beginning, but as we stood there and took photos, they got used to the idea of being looked at, and went back to foraging. Eventually, as the sun was about to set, they relaxed and sat back to start grooming each other. They are classified as “endangered” in the IUCN red list, just a step up from the designation of “critical” which precedes extinction. The main danger they face is habitat loss, although, since they live near dense human habitation, there is incidental threat to them from power lines and dogs. The forest floor was quite dark as we walked back to our jeep, wondering whether the sun was setting on the species too.

Clouded Leopards

Clouded leopards (Neofelis nebulosa) are shy nocturnal creatures which spend days sleeping on branches of trees. In retrospect I realize that we were really lucky with wildlife sightings in Tripura. We saw two of these rare beasts in the Sipahijala wildlife sanctuary. Its habitat must have once ranged right from the central Himalayan range eastwards to Taiwan, across most of south eastern Asia and southern China. Now the population is fragmented; but a patchwork of forests and reserves from the Chittagong hills in Bangladesh, across Tripura and Mizoram, and into Myanmar holds a small number of these threatened animals classed as “vulnerable” by IUCN.

We spotted one sprawled across a sturdy branch near the bottom of the forest canopy above us. The grey pelt with the patches of darker fur give it its name. After a long unsuccessful wait to see its face we moved on, but luckily within a few hundred meters we saw another individual sleeping with its face towards us. We must have made some noise, because it raised its face a little, yawned, and then lay back down again. A list of sightings in the wikipedia page talk about a cluster of photos, apparently the first of this animal, taken in the early years of this decade, right about when we saw these animals. That makes me think that there must have been changes in land use just around then. The black topped road that allowed us to see these two magnificent cats probably were the first signs of human encroachment on their territory. It is sad to realize now that travelers like us are signs of the very destruction that we would like to prevent.

Day of lost species

November 30 is designated the Remembrance Day for Lost Species. I think I will use this time to refresh my memories of Phayre’s leaf monkey (Trachypithecus Phayrei, also called the spectacled langur). We saw a family group of six or seven (this included a juvenile) in Sipahijala wildlife sanctuary, sitting on a tree, munching away at leaves. At first we thought they were the familiar rhesus monkey, but when we looked at them we realized they were quite different. They are smaller, and the white fur around the eyes, the spectacles, is as distinctive as the moustache. The group size and behaviour was typical. When the juveniles are 4-5 years old they leave the group. Individuals can live up to an age of abbout 20 years.

Leaf monkeys developed in Southeast Asia about three million years ago and have radiated into about twenty living species, mostly threatened. The case of the Indian population of Phayre’s leaf monkey is typical. They are well protected in a few isolated sanctuaries, there are some international efforts at conservation, but the protected areas are small and well-separated from each other. As a result the populations are now quite inbred. The situation is not much better over the rest of its range: Bangladesh, Myanmar, Thailand, Laos, Vietnam and southern China. Much of this region is densely populated, and forest land is being lost fairly rapidly.

The spectacled langur is classed as “endangered” by IUCN. If habitat loss continues, it will inevitably slide to “critical” and then to “extinct”. I have encountered many beautiful and strange species since 2005, when I started to visit wildlife reserves around India. Sadly, a large fraction of them are threatened.