Tuesday, September 27, 2011

The not-so-black bulbul


The trails of Namdapha National Park are treacherous, but they almost always seem to lead to wonderful new discoveries. How can one convey the excitement of a journey like this? The bamboo bridges you cross are rickety and fragile, held together only by cane; and the water you hope you will never fall into is freezing cold. Returning after days of tiring foot-slogging in the temperate forests and rhododendrons high up in the hills, we reached the village of Hazulu, where we were staying at the home of a friend. Along with a few others, I was on a Rufford Foundation funded bird survey for the Nature Conservation Foundation in the high altitudes of the hills to the east of Namdapha National Park in Arunachal Pradesh, near India’s border with Myanmar. And it was in Hazulu that I saw the bird.



blackbulbul1_ed

Black Bulbuls (Hypsipetes leucocephalus) are one of the commonest and most conspicuous bird species in the Himalaya and the Western Ghats. Birders who have spent time in these areas will be familiar with huge, raucous flocks of these birds flying over the forest canopy and feeding in fruiting trees. With smoky-black heads and bodies, and thin, coral-red bills, these birds are impressively attired, but balance their visual appeal with a range of loud and piercing cries, which some might call ‘cheery’, but are often more capable of inspiring irritation than joy.
India has three subspecies (or races) of Black Bulbuls. None of these races are strictly migratory, but flocks seem to move long distances in search of food, and changes in weather will often result in the almost magical appearance or disappearance of Black Bulbuls. In BR Hills (southern Karnataka), areas silent one day will become cacophonous the next, ringing with the squeals and cries of vast numbers of Black Bulbuls. It is like watching a session of the Lok Sabha in progress.
Asia has ten Black Bulbul races, from Afghanistan in the west to Vietnam in the east1. Three of these races have white heads (now you know why they’re called leucocephalus!), and breed in south China, migrating in winter to parts of Myanmar, Thailand and to other countries in Southeast Asia. These birds are certainly more handsome than their drabber Indian cousins, with bright white heads contrasting strongly with black bodies and red bills. The Indian subcontinent has only once seen these birds, in March 1995 in Bangladesh2.

blackbulbul2_ed

So imagine our surprise when we found these birds in Arunachal Pradesh! The friend who was hosting us told us first that there were strange black bulbuls with pure white heads around, we were incredulous and a bit dismissive. Juveniles, we said, whose pale grayish upperparts had been exaggerated into white. But the next morning brought a shock. In the persimmon orchards near the village were huge flocks of the ‘normal’ Black Bulbuls – and mixed with them in small numbers were birds with snow-white heads! They were spectacular. Even more so because they mixed freely with the all-black Black Bulbuls, and stood out in an otherwise drab flock. We found these birds once again at another village, again in a persimmon orchard, with other Black Bulbuls.
The resident Lisu people in the area say that these birds have been visiting the area for the past two winters, and have not been seen before. They should know, because Black Bulbuls frequently raid orchards in the area, and the local people know them well as a pest. In the Lisu language, they are known as Chamtakye. What makes these records really interesting is that these birds have been visiting the area for only the last two years. Global warming and changing climate has the potential to change the routes and timings of bird migration, and one could speculate that these sightings are the result of recent climate change in the area.

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