The real chicken

All the chicken that you eat has probably descended from this colourful bird found in all jungles that I have visited. The red jungle fowl (Gallus gallus) was domesticated in India about 7000 years ago, and the wave of domestication spread east and west from the Ganges basin. It is likely that the yellow legs of domesticated chicken were derived from a hybridization with another wild species called the gray jungle fowl.

I haven’t often seen one of these birds on a tree. So this one on a tree in good light was definitely something to be photographed. Its glossy black tail showed highlights of green and purple in the light. Note the gray legs; that sets it apart from domesticated variety. The domestic variety is also smaller and less brightly coloured. As I watched, this bird flapped its way down from the tree. Its flight is so ungainly that I wondered how it got up there in the first place.

Sexual politics in the jungle

A couple of days ago I wrote about how gender shapes chicken and their ancestral relatives, the red jungle fowl, Gallus gallus. Males fight each other to try to monopolize breeding with groups of females. This leads to larger sizes and extreme combativeness among males. The female is solely responsible for rearing chicks. Not only is she smaller, she is also drab coloured, so as to be less noticeable. The pattern of males being larger and more aggressive than females is also seen in other animals with similar social organization, for example, spotted deer (Axis axis), lions (Panthera leo), monkeys such as Northern Plains Langurs (Semnopithecus entellus). There are conjectures that sex-linked size and aggression in Homo sapiens is also due to social organization of this kind when our ancestors roamed the grasslands of Africa.

Thurber's cartoon

One of the more commonly visible birds in Pench national park was the Oriental honey buzzard (Pernis ptilorhynchus). The first one we saw was sitting on a nest, probably incubating a clutch of eggs (featured photo). The Family saw it instantly since she was looking through her new binoculars. I was peering through my camera, and I saw the nest but not the bird, until I zoomed the image. We kept seeing these birds through the next couple of days: flying low over us, sitting on a branch, diving into the grass. Once I photographed it on a branch (photo below), just before it dived into the dry grass below the tree. I could see it wrestle and worry something in the grass, so I waited for it to emerge with something in its beak. Unfortunately it appeared without anything and flew away.

Male oriental honey buzzard in Pench National Park

This was the breeding season, and clearly the intense activity was related to that. The females sat in nests, either brooding over eggs, or looking after hatchlings. I guessed that probably the males were doing most of the flying. Later reading told me an interesting fact: apparently in this, and many other species of hunting birds, the male is smaller than the female. The reason again seems to do with social organization.

In honey buzzards and other raptors, a male and a female bond as a breeding pair. The pair cooperate in raising the young. The mother spends more of her time in the nest, while the father spends longer periods foraging for the family. The wing span of male and female honey buzzards is about the same. So the smaller body of the male makes it more manoeuvrable, and a slightly better hunter. The same holds true for other hunting birds. Interestingly, those which hunt faster prey have relatively smaller males. Vultures show almost no size difference between the sexes.

Traumatic beginning of adulthood

Interestingly, all birds abandon the young once they are grown. This is again a theme that recurs throughout the animal kingdom, even among H. sapiens. To get back to our main theme, the full story of sexual dimorphism among birds may be more complicated than this. Studies show that strongly coloured males and drab females arise in bird species where the male tries to dominate a breeding group of females, but a significant fraction of the offspring are not the dominant males. This is extreme sexual politics. However, the mutually supportive roles of the two parents in the cooperative rearing of offspring prevents sexual politics from arising amongst honey buzzards.

The Chicken and Tyrannosaurs

We eased into the jungle with a sighting of the red jungle fowl, Gallus gallus. There are two interesting bits of information about these birds. The first is an insight due to Darwin himself, who realized that this is the ancestor of all the chicken which run around in farmyards across the world. This story has been enriched by modern molecular data. These established that there were gene exchanges between domesticated and wild populations, probably due to chicken which fled the coop. It is likely that chicken were domesticated multiple times in different places, and the domestic variety was crossed with other related wild species. The first domestication probably happened about 8000 years ago in India. Although chicken is the default meat in India today, my grandparents never liked it. Their generation thought of chicken as faintly unclean. I wonder how many cycles of food fashion have affected the chicken in its millennia of association with humans. The second fact is that Gallus gallus is the closest living relative of Tyrannosaurs, a fact that was only discovered in 2008 after T. rex tissue samples were first found.

These ancestral chicken wander around the undergrowth in the jungles of Pench National Park, kicking up leaves and pecking at things like thuggish dinosaurs. They are wary of humans and disappear quickly into thickets when they see people. So the photos you see here are about the best I have ever got. The large male (featured photo) has a glossy black tail which shows iridescent greens and blues, rich dark brown and orange back, dark and glossy underparts, and an orange and yellow neck and crown feathers. The individuals we saw had big red combs, small wattles, white ear patches, red eyes and a strong curved beak. I always thought the much smaller females were drab, until the light caught the one whose photo is below. Then I realized that they are a lovely golden-gray in colour.

The remarkable sexual dimorphism is selected by the life style of this bird. The dull colours of the female serve to camouflage her as she tends to eggs and chick, a task that she performs alone. Selection pressures, on the other hand, drive the male to be larger, in order to be able to overcome rivals and maintain its harem. The same pressures make it aggressive enough to be the stars in cockfights around south-east Asia. Interestingly, the comb and wattle are subject to sexual selection. Apparently the females of the wild species prefer larger combs and are indifferent to wattles. You can see the result of this preference in the featured photo.

Female red jungle fowl in Pench National Park

With the intense heat it is hard to accept that this is still spring. The big male had chased away all other males from its winter’s flock, and was surrounded only by a few females. Moreover, it still had its breeding plumage. From June to the end of the monsoon its warm gold neck feathers will be replaced by dusty black eclipse plumage. Except in springtime, the red jungle fowl lives in mixed flocks in which males and females have separate but strict “pecking order”.

It seems that there has been little study of the social structure of these birds, although it is recorded that there is a variety of different calls. Some of these calls are communicative. Our guide was of the firm opinion that these birds are good negative predictors of the presence of tigers, because they run away before a tiger appears. I did observe this on one occasion when some of these ran from a muddy pool before a tiger family came along. Chicken will be chicken, I suppose.

That left me with the question whether Tyrannosaurus rex was also chicken, at least in the sense that it ran away from confrontation.