Summer Visitors and Some Residents
In the second part of our series on birds, our blog this week looks high and low amongst the canopies and undergrowth of Ranthambhore’s forests in the peak of summer. May and June are invariably the hottest periods of the year in Ranthambhore and as many trees lose their leaves and the grasses shrivel and retreat in the heat, few creatures of the forest bother to stir unless they absolutely must. Not so with our feathered friends. Summertime sees an influx of some migratory birds to Ranthambhore who are currently here to escape the chill of the hills, from as far away as Central Asia. Other, residents – such as our male peafowl – develop such outrageously brilliant plumages, they forced Charles Darwin to splutter, “the sight of a feather in a peacock’s tail, whenever I gaze at it, makes me feel sick.”
But before we move on to examining nuances of a peacock’s tail, a quick look at the dashing colours we are frequently seeing flying between the trees these days. By all accounts, birds are the most studied and frequently seen group of animals on earth. A casual walk in the garden will yield more bird sightings than sights of mammals, reptiles, or amphibians. But what explains the sudden profusion of colours in bird species (notably migrants) in summertime? This comes down partly to annual morphism, whereby birds (like many other species) will alter their colouration, streak patterns or feather structures to optimise their chances of mating successfully. Another reason for the vividness, is simply our own eyesight, which sees colours more (or less) vividly depending on the way light falls on a bird. As Simon Barnes observes, “bird feathers refract light like a prism”. For the birds themselves, colouration allows for instant recognition. One of India’s largest Kingfishers, the Stork-billed Kingfisher for example will be able to identify or recognise a fellow Stork-billed Kingfisher from its colour patterns. The eyes of birds are a complex and sophisticated construct with four known light receptive cones inside them, (we humans must make do with 3D vision). This allows birds to see colour in four dimensions. This effectively means that birds can see what we can’t.
Looking at the Indian (formerly Asian) Paradise Flycatcher, we are startled by the coppery-rufous-reddish-brown stream of its tail floating through the forest. A fellow flycatcher will likely see colours our eyes cannot even imagine, iridescent-ultra-violet shimmers which reflect light in the most bizarre ways. Males of the species are polymorphic, both white and rufous in colour. Females are rufous too but missing the streaming tail and were it not for their ability to see – and see as vividly as they can – the colours of certain sub-adult males would appear no different to the female flycatchers from their own.
In the case of the male peafowl – the peacock – the extravagant ‘tail-feathers’ seem to serve no purpose at all. A lot of research and counter research, argument and counter-argument has occurred and we are nowhere closer to known – for certain – whether a peahen will actually pick a mate based on the size of his plumage. What we are sure about – the opinion of learned judges of the High Court notwithstanding – is that peafowl reproduce like any other bird on the planet, through sexual intercourse. What is mistakenly called the peacock’s tail does in fact grow out from its back, covering its lower body and trailing it like a cloak or shimmering gown. It is not much use as camouflage in Ranthambhore’s dry-deciduous forests in summer time.
One of the surest signs of the arrival of Summer are the regular bursts of yellow flying low between trees and waterholes. These are not nuggets of gold hurtling through the air, but the flight of our Golden Orioles. Nothing stands out more starkly against the dry canopy of the Dhok trees than the passerine Orioles on their branches. Flying at speeds of almost forty kilometres an hour, you can often miss them. But of all the summer visitors to Ranthambhore, the one you are most likely to miss, unless you are very lucky or unless it comes and presents itself to your vision is the Indian Pitta. This small creature, barely twenty centimetres in length resembles a largish quail that might have donned a ‘fancy-dress’. Superbly coloured but rarely seen, the Pitta inhabits the undergrowth – largely – through the day, skipping amongst fallen leaves foraging. Although it is rare to see one up a tree, that is where they perch.