Towards the end of June 2008, Tan Teo Seng brought me two old and used nests of the Baya Weaver (Ploceus philippinus).

I was interested in making a detailed study of these nests (left), namely the fibres and strips of leaves used and how these materials were put together. Madoc (1956) reported a total of 3,437 fine strands of grass, varying in length from 2.5 to 60 cm were used in a nest. And this was only the so-called “male” nest - the partially completed nest minus the downward pointing entrance tunnel that is usually added once the female gives her approval.

I sat down and tried to untangle the fibres, count them and measure the longer ones. For a few days I tried to do so but with partial success.

There were a total of 260 fine fibres making up the entrance tunnel. These were easily untangled as they were loosely weaved around one another and the ends never knotted (below left). The longest was 42 cm long.

Untangling the outer layer of the main nest posed much problem. Many of the fine fibres ran the length of the nest, from top to bottom. The top end of these fibres invariably originated around the nest attachment - firmly twisted round and round as well as knotted to a twig or twigs. The other end was simply knotted around other fibres at the lower part of the nest. Along the way, there were a few entanglements as other fibres were twisted round it. Others fibres ran down the nest, to turn sideways or upwards, twisting round others in the process (above right).

Many of the fine fibres ran round the nest, breaking up into two halves way down, each end again knotted, while along the way it may be twined around other fibres and narrow leaf pieces. These fibres were relatively strong and rough along the edge, having come from the edge of grass leaves.

The inner materials were mostly narrow grass strips, placed along the length of the nest and not knotted. However, they were loosely tied together here and there. These leaf pieces were mostly dried and brittle, breaking off easily. Because of the irregular knotting and brittleness of the materials, an accurate count was not possible. I stopped counting after 500, covering only the surface of the nest, not counting the 260 fibres from the tunnel.

The longest fibre was 78 cm, although most were 40-60 cm long.

The inner nest chamber was lined with feathers, below which was a layer of floss from lalang grass (Imperate cylindrical) fruits (left top). A close examination of these feathers showed a total of 26 downs, semiplumes and retrices (left bottom). In nests that were earlier examined, feathers were never found.
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Reference:
Madoc, G. C. (1956). An introduction to Malayan birds. Malayan Nature Society, Kuala Lumpur. (revised ed.)

An earlier post dealt with the seven species of broadbills seen in the Thai-Malay Peninsula. This post deals with some of their nests.

The nest is an untidy woven structure, globular to oval, or pouched-shaped. It is hung some distance from the ground from overhanging branches. There is a side entrance, sometimes with a crude porch. The base of the nest is untidy, with strands of plant materials hanging loose. The inside of the nesting cavity is lined with green leaves. In many instances, the completed nest is adorned with bryophytes, spider silk and cocoon silk. This works well as a camouflage.

The nests of the Black-and-red (Cymbirhynchus macrorhynchos) (above left), Dusky (Corydon sumatranus) (above right), Long-tailed (Psarisomus dalhousiae) (below left) and Silver-breasted (Serilophus lunatus) (below right) are shown here.

Both parents help in nest construction, but with the Green Broadbill it is reported that only the female is involved (Bruce, 2003). Depending on species, nest construction can take between one to seven weeks, as the birds may collect nesting materials in small amounts. Generally, the birds do not reuse the old nests.

Much of their habits and behaviour have yet to be recorded. The birds are both insectivorous and carnivorous. The recent posting of the Silver-breasted swallowing a cicada is a new feeding record.

All images by Willis.

Reference:
1. Bruce, M. D. (2003). Family Eurylaimidae (broadbills). Pp.54-93 in: del Hoyo, J., Elliott, A. & Christie, D. A. eds. Handbook of the birds of the world. Vol. 8. Broadbills to Tapaculos. Barcelona: Lynx Editions.
2. Wells, D.R. (2007). The birds of the Thai-Malay Peninsular. Vol. II, Passerines. Christopher Helm, London.

This post is a cooperative effort between NaturePixels.org and BESG to bring the study of bird behaviour through photography to a wider audience.

Tan Teo Seng brought me a nest of the Yellow-vented Bulbul (Pycnonotus goiavier) from his fruit farm in Kota Tinggi, Johor, Malaysia (above). The chicks had just fledged and he collected the nest that was built attached to the slender stems of his hibiscus bush (Hibsicus rosa-sinensis). The plant is less than a metre tall but very bushy, such that the birds built the nest near to the ground.

The nest is a typical cup-shaped structure that the Yellow-vented Bulbul builds: 11 cm diameter and 8 cm high. The nest cavity is of 6cm diameter. It sits on a bed of dried leaves held in place by the fern stems.

The nesting material is mainly the pliable branched stems of the Dragon’s Scale Fern (Pyrrosia piloselloides) (left). These stems make up the outer layer of the nest, the longest being 32 cm. They are also used to attach the nest to the three slender main stems of the hibiscus.

Inner to the fern stems are a layer of dried leaves, including grass and bamboo leaves. Plant fibres line the inside of the nest cup, with a few strands of slender, herb stems.

The nesting materials consist of: 22 dried leaves, of which 3 are of durian (Durio zibethinus); 83 pieces of fern stems (Pyrrosia piloselloides); 24 bamboo leaves; and 118 fibre strands.

I was trimming my starfruit tree (Averrhoa carambola) to remove the branches that were infringing on to my neighbour’s airspace. When collecting the branches, I was surprised to find a small nest attached to one of the end branches. So the nest was constructed high up the tree.

It was a smallish, oval nest, 14 x 8 cm, had a round opening 4 x 4 cm near the top (above). It was an untidy structure, with fibres sticking out all over the surface, looking like a mass of dried plant matters stuck to the branch.

The nest was firmly attached tied to the branch with masses of fibres. The round opening was lined with a defined rim of twisted fibres forming a distinct rim.

The fibres were carefully removed, identified and counted. Most of the fibres came from banana (Musa) and palms, making a total of 637 pieces, the longest being 31 cm. There were also 4 raffia strands and a single grass inflorescence branch. Loose lalang grass (Imperata cylindrical) floss scattered about the inner lining of the nest. There were also a few pieces of what looked like yellow spider cocoon silk, not specifically used to bind the fibres.

The Common Tailorbird (Orthotomus sutorius) has always been around the tree, foraging for insects, mostly ants. So the nest was most probably that of the tailorbird. The bird is about 11-13 cm in length and appears to fit the nest.

Also, earlier postings of Common Tailorbirds’ nests appear to be of similar size and shape. However, they were always built inside one to a few leaves stitched together like leaves of simpoh air (Dillenia suffruticosa), ginger plant or garden creeper.

Can it be that this nest is incomplete? And that when completed one or more larger leaves (taken from somewhere else) would be incorporated?

“Round and oval objects are hanging on the branches of a mangrove tree, swinging slightly when the wind blows (above). These are the nests of the Baya Weavers (Ploceus philippinus) (below top). There are more than ten of them, hanging from the branches of a tree in Sempadan swamp along Bogowonto river in the coastal village of Pagak Purworejo, Indonesia. This is a favourite nesting area of these birds.

“The nest architecture is complicated. Each nest is constructed from grass leaves, plaited in a very complex way.

“The nest is as big as a soccer ball, oval, stretched with a hallway and an entrance with a 10 cm diameter opening (left bottom). This entrance is on the underside of the nest with less dense plaited grass. The upperside of the nest is spherical and the grass plaited is thick and dense.

“Other nests seem to have different shapes - rounded with two openings beneath. Nest construction here seems to be incomplete, probably the male Baya Weaver is having a rest or cannot find enough nest materials? Or probably the male does not want to continue building his pretty house for the female, because she is not pleased with the house he built and has to be abandoned by the architect.

“It is not only humans that have special courtship behaviour. Baya birds, in order to attract a female, needs to pay a “bride price” or a guarantee of a home to raise the young. The male has to build a “castle” for the female before the copulation is allowed.

“Not just weavers but many other birds that live in the tropics such as Indonesia, have to build a nest before copulation.

“The many male birds can be seen competing with one another to collect materials and construct the nest. They are all busy arranging the grass leaves piece by piece, plaiting them carefully to slowly construct the nest before presenting to the female for approval.

“The bird that builds the most “beautiful and comfortable” nest will win a female for the current breeding season.”

Text by Oka Dwi P., images by Swiss Winasis.
This post was received courtesy of Sunaring Kurniandaru, Kutilang Indonesia Foundation, Yogyakarta, Indonesia.