The BAYA WEAVER is a
weaverbird found across the Indian Subcontinent and Southeast Asia. Flocks of
these birds are found in grasslands, cultivated areas, scrub and secondary
growth and they are best known for their hanging retort shaped nests woven from
leaves. These nest colonies are usually found on thorny trees or palm fronds
and the nests are often built near water or hanging over water where predators
cannot reach easily. They are widespread and common within their range but are
prone to local, seasonal movements mainly in response to rain and food
availability.Among the population variations, three subspecies are recognized.
The nominate race philippinus is found through much of mainland India while
burmanicus is found eastwards into Southeast Asia. The population in southwest
India is darker above and referred to as subspecies travancoreensi.
DETAILS
These are sparrow-sized
(15 cm) and in their non-breeding plumage, both males and females resemble
female house sparrows. They have a stout
conical bill and a short square tail. Non-breeding males and females look
alike, dark brown streaked fulvous buff above, plain (unstreaked) whitish
fulvous below, eyebrow long and buff coloured, bill is horn coloured and no
mask. Breeding males have a bright yellow crown, dark brown mask, blackish
brown bill, upper parts are dark brown streaked with yellow, with a yellow breast
and cream buff below.
BREEDING
The breeding season of the baya weavers is during the
monsoons.The breeding condition is initiated by environmental characters such as
day length and comes to an end after summer although this termination is not
influenced by short day length as in temperate birds.They nest in colonies
typically of up to 20-30, close to the source of food, nesting material and
water. Baya weavers are best known for the elaborately woven nests constructed
by the males. These pendulous nests are retort-shaped, with a central nesting
chamber and a long vertical tube that leads to a side entrance to the chamber.
The nests are woven with long strips of paddy leaves, rough grasses and long
strips torn from palm fronds. Each strip can be between 20 and 60 cm in length.
A male bird is known to make up to 500 trips to complete a nest. The birds use
their strong beaks to strip and collect the strands, and to weave and knot them
while building their nests. The nests are often built hanging over water from
palm treesand often suspended from thorny Acacias and in some cases from
telephone wires Although the birds prefer thorny trees, they sometimes use
avenue trees in urban areas. Nests are often located on the eastern side of the
tree, where they are believed to provide shelter from the Southwest Monsoon;
however, late breeders are more likely to build their nests in other orientations
relative to the trunk of the nest tree. Abandoned nests are sometimes used by
mice (Mus booduga) and other birds such as munias.Nests are built mainly in colonies but isolated nests are
not unknown.Nests are often built from thorny Acacia or palm trees ( mainly
Phoenix sylvestris )and hang over open water. Young males may build experimental
nests among reeds. In Burma, birds often build nests under the eaves of
buildings, but this habit is uncommon in India.The males take about 18 days to
construct the complete nest with the intermediate "helmet stage"
taking about 8 days. The nests are partially built before the males begin to
display to passing females by flapping their wings and calling while hanging
from their nests. The females inspect the nest and signal their acceptance of a
male. Once a male and a female are paired, the male goes on to complete the
nest by adding the entrance tunnel. Males are almost solely in charge of nest
building, though their female partners may join in giving the finishing
touches, particularly on the interiors. Females may modify the interiors or add
blobs of mud.A study has found that nest location is more important than nest
structure for the female when it selects the nest and mate.Females prefer
nests high in trees, those over dry land, and those on thin branches.
Both males and females are polygamous. Males build many
partial nests and begin courting females. The male finishes the nest only after
finding a mate. The female lays about 2 to 4 white eggs and incubates them for
about 14 to 17 days. Males may sometimes assist in feeding the chicks. The
chicks leave the nest after about 17 days. After mating with a female the male
typically court other females at other partially constructed nests.
Intraspecific brood parasitism is known, that is, females may lay their eggs in
the nests of others.
Young birds leave the nest in a juvenal plumage which is
replaced in their first moult after about four to six months. The young
disperse to new locations not far from their nest and young have been located
up to two kilometres away from their origin.Females are capable of breeding
after a year while males take half a year longer. Prior to breeding they go
through a prenuptial moult. Adults also go through a second moult after
breeding and thus there are two moults each year.Histochemical studies have
shown increased lipid metabolism in the crown region of male Baya during the
breeding season. Lipids are known to be involved in the transport of the yellow
carotenoid pigments that form the crown and are subsequently metabolized.
The nest, being suspended from thorny trees and overhanging
water, is protected from many predators, but nest predation by crows is not
unusual. Brood may also be destroyed by lizards such as Calotes versi color or rodents such as Vandeleuria oleracea which may take over the nest.Nests may
sometimes be taken over and used for nesting by Indian silverbills (Euodice
malabarica).
IN CULTURE
A widespread 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. Clay, however is known to be used in the nests of baya weavers. Males
alone have been seen to add blobs of mud and dung to the nest chamber prior to
pairing with a female.It has been suggested that the clay may help to stabilise
the nest in strong winds.
In earlier times, the baya weaver was trained by street
performers in India for entertainment. They could pick up objects at the
command of their trainers.They were trained to fire toy cannons, string beads,
pick up coins and other objects. These uses have been noted from the time of
Akbar.
COMMON NAMES
Tokora
Tokora chorai (Assamese);
Baya,
Son-chiri (Hindi);
Bayya chirya ;
Baya chadei (Oriya);
Sugaran (Marathi);
Tempua (Malay);
Sughari (Gujarati);
Babui(Bengali);
Parsupu
pita,
Gijigadu/gijjigadu (Telugu);
Gijuga (Kannada);
Thukanam kuruvi (Malayalam);
Thukanan-kuruvi (Tamil);
Wadu-kurulla,
Tatteh-kurulla,
Goiyan-kurulla(Sinhala);
Sa-gaung-gwet,
Mo-sa (Myanmar);
Bijra (Hoshiarpur);
Suyam (Chota
Nagpur),
Bagra(Maithili)
