Sapphira By Gargi Mishra

Pigments impart colours to us, starting from our skin to the flora and fauna. But exceptions are the bright blue, white and violet feathers of many birds. 

What causes the above colours in these birds? I wonder every time when I see a blue bird like Tickell's Blue Flycatcher or a Verditer or an Indian roller. 

Vinod Saranathan of the Oxford University's Department of Zoology has some answers. He says, "Birds have evolved (as many as 44 species) to produce shorter and middle wavelength colours such as violet, indigo, blue and green structurally. The biophotonic nanostructures present in their feathers scatter light photons. No known blue pigments are found in vertebrates."

Here, I introduce TICKELL'S BLUE FLYCATCHER (Cyornis tickelliae), one of the most sought-after by the birdwatchers. S/he has been named after the British ornithologist Samuel Richard Tickell (born in the Cuttack city of Odisha). It is believed that the ornithologist had attributed the scientific name of the bird based on his wife's name. 

Tickell’s Blue Flycatcher is an Indian resident but moves locally depending upon the weather conditions. Their preferred habitats include bamboo groves, bush jungles, shady glades and abandoned plantations. 

Naturally, we spotted them in the bamboo groves in Camp Hornbill (Kyari Village, Uttarakhand). We spent half-a-day to observe and study the blue feathers of Tickell's Blue Flycatcher. 

The dark blue upperparts of the bird appeared shimmery with a touch of sapphire blue on his forehead, eyebrows and shoulder patches. The contrasting rufous-orange colour of throat and breast were merging with the off-white abdomen and the flanks (in some cases the flanks appear orangish too). The under tail-coverts were white. Brown iris, black bill and bluish brown legs are few other physical features of the bird.

Girls are duller in shade. Juveniles appear much scaly and streaked with only blue wings and tails.

I observed something amazing. The colour of feathers changes when the bird perches out of sunlight. The feathers appear glossy and darker blue under direct sunlight whereas they appear dull under shade (here I recall the research work done on the structural colouration of bird feathers by Vinod Saranathan). It is a proof that the Tickell's Blue Flycatcher's feathers have structural colours not pigments. 

Let me simplify the "structural colour" of a bird. A bird's feather has tiny air pockets in the barb (barbs and barbules are the primary and secondary branches of a feather respectively), which look like sponge with air bubbles under an electron microscope (called nanostructures). "These nanostructures absorb certain colours from the visible light. But what they cannot absorb is reflected from the structure and we see that particular colour." explains Vinod Saranathan. 

The one we spotted in Camp Hornbill was not very shy but at first, a little hesitant to come nearer. Finally, our unfettered efforts and stillness earned his confidence. He perched at a distance of only 5/6 ft. from us on a bamboo twig and later on a wire fence. He was occasionally flickering his tail as if saying, "I know you're here, but I trust you." 

We heard him replying to a sweet diminutive metallic 'trill trill' calls. But not sure about the owner of those calls whether it was a girl or a boy or a juvenile because the one was well hidden inside the canopy. The diving dedicated for catching flies and midges was often accompanied with "click-click" calls. The boy had let out a panicky "churr, churr" call when he didn't approve our presence near his mansion earlier. That might be an alarm call to alert others about our presence. 

Confusion among a Tickell's Blue Flycatcher and that of a Blue-throated Blue Flycatcher is very natural because both of them have uncanny resemblance. But the latter has a blue throat as the name suggests whereas Tickell's has an orange throat. 

In this age of habitat loss and lack of food security, Camp Hornbill is definitely a promising habitat for many beautiful birds. I hope this little Sapphira would definitely get ample opportunities here to thrive in peace. 

Photos By: Gargi Mishra 

Place: Camp Hornbill, Kyari Village, Uttarakhand