Architects

The difference between artificial and natural objects appears immediate and unambiguous to all of us. Analyse these judgements, however, and it will be seen that they are neither immediate nor strictly objective.

Jacques Monod (Chance and Necessity)

On the last afternoon, after our last safari in the forest, The Family and I took a walk through the fields outside the village. Hedges and trees around the fields of ripening wheat were full of birds. We stopped to look at a thorn tree in the fields, close to the lake’s edge, from which four incomplete nests of Baya Weavers (Ploceus philippinus) dangled. There was quite a bit of activity, with birds landing on the tree or nests, and going in and out of them.

As I watched this activity, I began to doubt my identification. I’d thought Baya weavers were unambiguously identifiable. The females are drab, the size and colour of sparrows, but with a little more dark on them. The males have gold on the head and neck. There were females at the nest, but hardly any males. November is also the end of the breeding season in parts of India. I thought that if this were indeed a Baya Weaver’s nest and in use by the females, then it should have had a completed entrance tunnel by now. Would the nest be incomplete in November, and be visited by females with no males in sight? I began to doubt my identification. At the same time, I could rule out all other weavers by either colour or nest shape. What was going on? It was time to consult The Commander.

Elegance is best left to cobblers and tailors

Albert Einstein, quoting Ludwig Boltzmann

He assured me that my identification was correct. This was the Baya weaver. Since the entrance tunnel was missing, either the nests had been abandoned because no female had selected it, or the local breeding season was not yet over. A close look at the nests shows that the material at the edge of the opening is still green, so it could be that the nests are still being inspected by the females. Perhaps in this region the breeding season is not over. The ample water in the region could be a reason why the birds breed in winter when the crops are ripening. When you observe the world, little is rule-bound. There are local circumstances and caveats which constantly have to be taken into account. Pity the poor scientists who have to disentangle these accidents to get the underlying nature of things.

I am quite fond of this photo I took immediately after we walked away from the nests. It shows a Black Drongo (Dicurcus macrocercus) and a Baya Weaver. These two birds act in ways which we often think is special to humans. The drongo often warns other birds of danger, but can be a liar and a cheat: often giving alarm calls to make other animals flee so that it can steal food from them. The weaver is an architect and starts to build complex knotted nests in its search for a mate, abandoning it half built if no female likes it. Is there really an yawning gap between humans and the rest of the natural world?

Old favourites and a new acquaintance

I’d gone to Bhandup pumping station last week in the hopes of seeing an Eurasian wryneck for the first time after a couple of years. I heard the pair, but didn’t see them. The find of the day was instead the Malabar starling (Sturnia blythii, aka Blyth’s starling). A flock of glossy birds surveying their surroundings from a high perch were a lifer. The light was wonderful and I could see all the defining details: the yellow bill with a bluish-ash base, the white head with contrasting chestnut belly, and the grey and black wings and tail. This bird is resident in India, and was split off from the migrant species called the chestnut-tailed starling (Sturnia malabaricus) with which it was confused even at the beginning of the century. As I took the photos you see above and in the gallery, I realized that I’d been hearing their chitter for a while.

Most of the other birds I saw that day were old acquaintances. We arrived before sunrise, and the early part of the day was not very good for photos. So I missed shots of a common tailorbird (Orthotomus sutorius) which spent some time on a branch in front of my eyes. My photos of an eastern marsh harrier (Circus spilonotus) trying to snatch prey in midair have digital noise and are beyond rescue. Some of the others you can see in the gallery above. I should really start keeping my bird lists, but I can’t bring myself to admit that I’m slowly turning into a twitcher.

Baya weavers

Baya weaver (Ploceus philippinus)

The wasteland behind Bhandup pumping station was full of chittering flocks of Baya weaver birds (Ploceus philippinus). They breed in monsoon, and the males were still in their startling yellow breeding plumage. They looked wonderful in the soft morning light. Among these birds the male makes the intricate hanging nest, mates, and then leaves the rest of the child bearing to the female. I began to wonder how the female chose the nest and its maker. When it comes to common birds, almost every question you ask will have been answered. I found that the question had been answered fourteen years ago.

The female’s choice mostly depended on the location of the nest: nests high up on strong branches in thorny trees were preferred. This preference cannot be unknown to males, so there must be intense competition between them. The result is that the female most often chooses males who are able to chase rivals off their chosen site, whether she means to do it or not. In captive flocks the males are seen to create a pecking order which is pretty stable, indicating that this kind of competition is resolved with a minimum of physical violence. Among equally desirable sites, the female chooses nests made of finer fibers. Since nesting occurs during the monsoon perhaps this allows nests to be better knit and dry. So male behaviour seems to be pretty strongly driven by the choices of females. I wonder whether it works the other way round too.

The rest of the story

White eared bulbuls

I’d started a story from the middle when I posted about flamingos in the backwaters of Mumbai. In order to finish the story, I have to give you its beginning. We gathered before sunrise in the region between the Thane creek and the aeration ponds of the Bhandup pumping station. As The Night drove in, a flock of flamingos flew overhead. The sky was the light grey just before dawn. A coucal flew into the bushes ahead of us. As the horizon dipped below the sun, and the sky began to light up, we walked back down the canal.

We saw several birds on our slow walk. I’d seen most of the waders, and could still recall their names. I’ve just begun to notice the warblers, and the clamorous reed warbler which we saw was a lifer. One interesting thing about birds is that they are creatures of habit. If in addition they are territorial, then they tend to appear at the same time in the same place every day. We met birders who come to this place very often, and sometimes they told us to look out for some bird or the other, because it should appear soon. It usually works. Passing on socially acquired knowledge is characteristic of our species, isn’t it?

Eventually we went on to ducks and flamingos, but those are stories I have already posted.

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