"Birds from different species recognize each other and cooperate.
Researchers show for the first time how birds from two different
species recognize individuals and cooperate for mutual benefit."
When I read the lead above on Sciencedaily.com, I was puzzled. Isn’t “for the first time” an over-statement? As an amateur but avid bird-watcher, occasional Bird-writer, and a bird-book collector, I know that birds do very well at recognizing and cooperating between species. Most bird books on Nepal say so, dating back many years. A “first time” doesn’t apply to what’s already documented.
Birds communicate in chirps, tweets and twitters, cries and shrieks, hoots and caws, clucks and crows. And they sing melodiously, especially to attract mates. Bird vocalization may express fear, alarm, or pure pleasure. A few species are noted for duet calls; that’s when a male bird sounds off immediately followed by his mate’s call, so soon that it seems like one voice speaking.
Not all bird sounds are vocal. While reading up on the subject, I learned new words, like ‘sonate’ -- the act of producing non-vocal sounds intentionally modulated by ‘non-syringeal structures' such as wings, tails and other feathers, As well as beaks and feet. Next time you see a Great Hornbill flying through the Chitwan forest, listen to its wings; such a sound as you might expect from a prehistoric paradactyl.
Babblers are one of the largest bird families in Nepal, with diverse, species-specific voices ranging from the ‘poo-koo-poth’ and ‘whert-whert-zzzzzz’ of Slaty-Headed Babblers; the ‘which-which-whichi-ri-ri-ri...’ of Common Babblers; the ‘tit tit’ or ‘chit chit’ of Red-capped Babblers; the ‘cheer’ of Striated Babbler; and the ‘beat-you, he’ll-beat-you’ of Spotted Babbler, to name a few.
The exotic and elusive Spiny Babbler (Turdoides nipalensis), endemic to Nepal, Is an especially good mimic with a variety of squeaks, chuckles, and chirps. Its Common call is a long, descending ‘tee-tar—tee-ter-tar—tee-tar’, preceded and concluded with a ‘preep—pip-pip-pip’. Its alarm call is a ‘churrrrrr.’Other Babbler alarms sound like ‘pee-a-wee’ of Black-chinned Babblers and ‘pic-pic-pic’ of Red-capped Babblers.
Why and how birds vocalize to communicate and cooperate in the bush is what the researchers featured in the Sciencedaily article have studied. They describe a type of Australian wren that not only recognizes individual birds from its own species but uses vocalization to form long-term partnerships with other species both to help defend shared space and forage as a group.
In Nepal such a discovery is old news.
Mixed Hunting Parties
I first heard of mixed hunting parties in ‘Search for the Spiny Babbler: Bird Hunting in Nepal’ (1953) by S. Dillon Ripley, a world-renowned ornithologist. Ripley describes them as –
“groups of birds commonly found in forest and scrub environments, roving in cooperative bands of mixed species, profiting from each other’s foraging behaviors. Salim Ali, India’s most famous ornithologist, once described a scene of ‘Babblers rummaging amongst the fallen leaves for insect food [who] disturb a moth which is presently swooped upon and captured in mid-air by a drongo...’and of a “woodpecker scuttling up a tree-trunk in search of beetle gallenes [that] stampedes numerous winged insects... promptly set upon by a vigilant flycatcher or warbler’.”
In ‘Birds of Nepal’(1976), Fleming, Fleming and Bangdel add Laughing Thrushes, Yuhinas and Warblers to various Babbler species in such parties. And Salim Ali, in ‘Indian Hill Birds’(1949), describes flocks of six or more Quaker Babblers (also known as Nepal Babblers)–
“invariably to be found among the mixed hunting parties of small Insectivorous birds that rove the forest. The birds hop from sprig to sprig, often clinging upside down, sideways or back to ground to peer into the angles of the leaf-stalks and various nooks and crannies for lurking insects...The clear, whistling, quavering song of four notes... is constantly uttered as the birds move about... The scattered members of a flock keep in touch with one another by a harsh, rather subdued ‘chur-r, chur-r’.”
In ‘The Book of Indian Birds’ (12th ed., 1996), also by Salim Ali’s books, Jungle Babblers are described hopping about in flocks or ‘sisterhoods,’ rummaging on the ground together, chattering and squeaking, “which sometimes develops into loud discordant wrangling.” This group behavior, Ali says, goes beyond foraging, for they are also known to band together to ward off attacks by owls, Hawks or cats. It’s called “mobbing” in bird lore, combining their voices to repel predators.
As Dillon Ripley searched for the Spiny Babbler in Nepal in 1947 (by special permission of the (then) Rana Prime Minister), he found one in a mixed hunting party while birding in low shrubs and heavy grass–
“Halfway down the slope and near a large bush, I heard a series of low chuckles and ‘querr’ noises. I stopped short. There must be a flock of laughing thrushes or babblers about, the sort of birds that go around in small family parties, constantly talking to each other. After waiting carefully, stock-still for several moments, I saw a group of birds hopping about ... They were dark and bulky-looking, as big as a thrush, and they flicked and flirted their tails as they hopped about, in the characteristic manner of the noisy nervous babblers or laughing thrushes.”
After collecting one as a scientific specimen, he described it as –
“A brownish bird the size of an American robin or an English Blackbird. The throat and upper breast were white, the rest streaked brown. The feathers of the upper side, particularly the forehead and crown, had stiff wiry shafts as did those of the throat. As this bird lay in my palm, I could think of no species of laughing thrush known to me which it remotely resembled...
“It was not really until the next day that I began to ponder seriously over my new bird... Holding my prize and thinking about It, I began to turn over all the Indian species in my mind. What could this bird be? In the field a problem like this was not an easy one when books were not ready to hand, when there were several hundreds of species to choose from. Finally, the stiff wiry shafts of the feathers gave the bird away... it could only be the Spiny Babbler... a species that had defied scientists for years. None had been collected for one hundred and six years, since 1843 and 1844...”
Despite its rarity in Dillon Ripley’s day, Spiny Babblers are fairly common in Nepal, though hard to spot. You may hear them babbling in cutover scrub Brush and tangled thickets where they move about singly or in small scattered parties. They’re a grayish-brown bird with white on face and chin, streaked and pale below, and the tell-tale ‘spiny’ feathers, stiff and wiry, around the throat.