Architect-engineer: Build it like the baya weaver

In many parts of India, the sight of a baya weaver bird, building its nest indicates that rains are around the corner. Identified by their bright yellow crest, there are four species of the bird indigenous to the country—the baya weaver, streaked weaver, black-breasted weaver and Finn’s weaver.

Once a common sight in India, weaver birds are today an endangered species. With rapid urbanization, the bird is vanishing from not just urban areas, but rural pockets as well and, the beautiful nests of these birds are hard to find on trees these days. According to the International Union for Conservation of Nature's, (IUCN) Red List Category, the baya is classified as a least concern species. However, this bird is not immune to threat, particularly related to human activities and is protected under the Indian Wildlife Act 1972.

<img class="wp-image-15149 size-full" src="https://indianarrative.com/wp-content/uploads/2020/09/P1-Male-baya-At-work.jpg" alt="" width="1000" height="746" /> The male baya weaver at work on its 'flat' (Photo: Mrityunjoy Kumar Jha)

After the lockdown curbs lifted, one fine September weekend, we went to Sultanpur wetlands in Gurgaon to shoot some common birds. The day started with lovely grey and black francolins, Knobilled ducks, Redshanks, flocks of egrets, common sandpipers and ashy prinias—busy with their early morning chores. On the way, we saw some Baya Weavers (Ploceus philippinus) building nests on a tree. We stopped to observe them. The males were in full breeding plumage, looking very handsome with their striking yellow headgear. It was a wonderful sight to behold nature’s expert architects in building one of the most beautiful nests of the world.

The male baya weaver has enviable building skills, and perhaps even some lessons on consent. The little, sparrow-sized bird will build nests from grass and leaves during the monsoon. They are woven in intricate, gravity-defying patterns, and the nests hang, rather than rest.

<img class="wp-image-15150 size-full" src="https://indianarrative.com/wp-content/uploads/2020/09/P4-Pair-in-the-nest.jpg" alt="" width="2048" height="1426" /> A pair of baya weaver birds in a newly built nest (Photo: Mrityunjoy Kumar Jha)

The responsibility of constructing these nests rests on baya weaver males. They tear long strips from leaves of grass, reed, palm or bamboo to use as “threads”. The work begins with tying leaf strips around an anchor point (it can be a branch, a palm leaf or even an electric cable) to hang the nest. Then with a loop here, a tuck there, and the twist of a knot, the bird will make a wreath before moving on to the master bedroom, and finishing with a narrow, downward-pointing tunnel as the front door.

Weaver birds’ nests look neat and clean and well finished, as if made by an expert, without straws sticking out. The nests have a definite design that includes a loop attachment to the branch, a roof, the egg chamber and entrance tube. This entrance is strategically located at the base and turned downwards to avoid entry of predators.

Normally, weaver birds sport a dull yellow color with black markings and look like a sparrow at a glance. “As breeding season approaches, the males grow brighter in color with the yellows and markings becoming more prominent. Nests are built over two week’s time and they are quite sturdy,“ said my fellow expert birder Kamal Sahansi. The female baya weaver looks exactly like common sparrow but they have a very lighter shade of yellow on their throat and chest.

<img class="wp-image-15151 size-full" src="https://indianarrative.com/wp-content/uploads/2020/09/P8-Bay-Weaver-A-male-baya-weaver-with-its-distinctive-yellow-crown-and-blackish-mask.jpg" alt="" width="2048" height="1398" /> A male baya weaver with its distinctive yellow crown and blackish mask (Photo: Mrityunjoy Kumar Jha)

So how the baya weaver bird engineer such a complex and intricate nest? Apparently, baya uses its claws to keep the grass thread in place around the branch and knots it. It even makes reverse windings to strengthen it further. According to the experts it is the product of a whooping 3,437 “threads” and each thread-stripped and converted to the nest is 20-30 cm long. The male baya takes about 18 days to build the nest making up to 500 trips to complete one.

Strangely, the male and female bayas have their works distinctly demarcated. While the male has the onus of building the intricate nests, the female brings up a hungry brood of chicks. The male baya, being a polygamist, is capable of acquiring many partners; he painstakingly weaves a splendid nest that is half-finished and invites a lover to inspect the construction. The male baya will build several nests on one tree, and then it waits for a female to come and inspect them. Females will check the nest during the 'construction process' and will not 'accept' it if it is not up to their 'standard'.

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The breeding season is usually from March to July. Females can lay up to six eggs and the chicks leave the nest after about 15-20 days. After that the male bayas break the old nests so that they can make new nest to attract a female to that.

The intelligence of the Baya weaver birds is said to have earlier prompted humans to train and use them as performers street but watching them work in live in their natural habitat lives might be more useful.

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A folk belief in India is that the baya sticks fireflies with mud to the nest walls to light up the interior of the nest at night. That’s an incredible vision.

These little birds are truly masters at building structures out of twigs, stems and other odds and ends. Watching them at work is, well, mind-blowing. The next time you see a nest, just remember what some birds are capable of creating!.