Posts Tagged 'plumage'

baya weavers nesting

Posted by on 04 Sep 2016 | Category: photography, prakriti

It is nesting season for the baya weavers!

Baya weaver birds are small, sparrow-size birds which resemble the sparrows during the non-breeding season. During May-June, as the breeding season approaches, their gonads (sexual glands) become active and the adult males develop yellow and black color plumage on head, breast and throat; and their bills also darken. By the time the monsoon starts, the males are in bright yellow summer colors, and ready for breeding through the monsoon season (June-September).

baya weaver nest building

Why do they breed during the summer monsoon? Obviously, the grass is green during this side of the monsoon! Baya weavers forage in flocks for seeds on wild grass like these below, which are plenty after the monsoon rains. This is also the time when insects are plenty, especially to feed their young. How many bayas can you count in the image below?!

a group of baya weaver birds feeding on grass seeds

Nesting success? Baya weaver nests are exclusively built by the males and then displayed to the females. What are the factors on which the female makes it selection? Among birds, elaborate nests and decorations built by males may help females to assess a male’s quality. One of the most popular architectural attributes of the weaver nest is the entrance tube, which can get as long as 90 cm. Female birds are also selective in choosing nests which provides safety (in terms of nest height and location). So what does the baya weaver base their selection on? Is it the architecture or the location?

baya weaver nest building at Pune, Maharashtra

Safer on thorny trees: Observation shows that the female weavers are inclined towards nests which are safely located in thorny trees, farther away from the trunk and situated high above the ground. Thornless trees have higher rates of snake predation than thorny trees. Nesting success also increases with with thickness of the supporting branch and for nests which are woven with fine fiber.  Thick branches may stabilize nests during strong monsoon winds, and may also be less likely to break.

baya weaver and a garden lizard against the blue sky

Despite these precautions, garden lizards like the one above, and tree mouse do occasionally raid these nests.

Some history: Baya weavers and their unique nesting nature were first recorded in Ain-i-Akbari, the 16th-century document recording the administration of Akbar’s empire, and which is part of the a much larger document, the Akbarnama. The Volume III translation by Colonel H. S. Jarret talks about wild/domesticated bayas: “The baya is like a wild sparrow but yellow. It is extremely intelligent, obedient and docile. It will take small coins from the hand and bring them to its master, and will come to a call from a long distance. Its nests are so ingeniously constructed as to defy the rivalry of clever artificers.”

Species: Ploceus philippinus
English: Baya weaver
Location: IITM colony, Pune, Maharashtra
Date: 3 Sep 2016

References:
1. Balasubramanian, K. S., & Saxena, R. N. (1973). Effect of pinealectomy and photoperiodism in the reproduction of Indian weaver birds, Ploceus philippinus. Journal of Experimental Zoology, 185(3), 333-340.
2. Fazl, A., & Jarrett, H. S. (1983). The Ain-i-Akbari:. Royal Asiatic Society of Bengal. (No. 61).

3. Quader, S. (2006). What makes a good nest? Benefits of nest choice to female Baya Weavers (Ploceus philippinus). The Auk, 123(2), 475-486.

nest raiders at our backyard

Posted by on 01 Jul 2009 | Category: photography, prakriti

One day we heard a lot of commotion just outside of our house. We saw 3 or 4 purple sunbirds, red whiskered bulbuls and yellow browed bulbuls at the same location, hovering and squeaking around. Though the possibility of a snake was there, it was ruled out because we saw a crow-pheasant (greater coucal) nearby, which is another enemy and nest raider of the smaller birds. Probably there is some bird nest nearby and the crow-pheasant was after it.

greater coucal, centropus sinensis

The greater coucal, Centropus sinensis, at the scene of action.

As usual, we took our camera and though the birds were in a distance, captured some photographs. These photographs were taken on 15 Feb 2008, from our home at Kerala. As usual, the photographs were processed and closely checked very late, more than a year later. We were taken in for a surprise. All of a sudden there is a snake in the picture! That too, a long snake with its long tail entwined all over the all-spices tree in our backyard…

purple sunbirds and the snake

The male purple sunbird, cinnyris asiaticus (~ nectarinia asiatica), as you see, is in the breeding plumage. They are glossy purple during breeding time and have brownish upper and greyish-white under sides during non-breeding time. You can see the predating snake sneaking through the all-spices tree on the right.

Birds, especially the smaller ones, have an effective (well, sometimes) defense system against snakes. If one of them finds a snake, they make sure that the whole world knows about it, by flapping and chirping out loud. This brings the rest of the community to the scene of action. Altogether, they make an aggressive attempt to mob and drive the snake away.

red whiskered bulbul, pycnonotus jocosus

Red whiskered bulbuls, pycnonotus jocosus, at the scene of action. We had earlier discovered that the red whiskered bulbuls are nesting nearby. Some of these >> red whiskered bulbul nests were photographed around the same time. So it is of ultimate interest to both these birds to get rid of the enemy off their domain.

yellow browed bulbul, lole indica

Yellow browed bulbul, lole indica, at the scene of action.