Baya Weavers Malaysia

Am posting these two amazing photographs of a group of baya weavers' nests. Really beautiful. Previously I made a posting about Baya Weavers at this link here, of several nests that I observed at Samudram Lake, Tiruvannamalai.

For absolutely no reason that I can understand some miscreant burnt down the acacia bush that was home to the lovely nests. It boggles belief that anyone could be mean-spirited to needlessly and spitefully burn down the tree and destroy the nests.

Maybe in Malaysia the nests in the above photographs are in a protected area, or maybe people there have a better understanding of conservation!

Smart Crows!

Further to my recent posting on Crows, found the following excellent stories about discoveries on the intelligence of Crows. Click on each of the three narratives for the full story.

Crows are the Einsteins of the avian world
Tailcams' reveal cleverness of crows
Crows can be craftsmen, too

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Crows may be smarter than apes

Researchers found evidence that the birds are able to outsmart people’s closest relatives when it comes to finding a way to access food without it falling into a trap.

Many studies have investigated the remarkable ability of crows from the Pacific island territory of New Caledonia to make tools from leaves, and customise them with great dexterity to extract grubs and caterpillars.Now a team from Auckland University, led by Prof Russell Gray, publishes what it says is "the most conclusive evidence to date" that the birds are indeed smart, showing that they can reason causally and use analogy in a way not seen even in our closest relatives, the great apes.

In the Proceedings of the Royal Society: Biological Sciences, Prof Gray, Alex Taylor and colleagues describe experiments that were designed to work out what was going through the birds' minds.

The scientists presented crows with the trap-tube problem, where an animal had to extract food from a horizontal tube in a direction that avoids a trap, which swallows up the treat so they cannot eat it.

This problem can be solved by associating the relation between particular features of the trap-tube, such as the position of the hole or colour of the rim of the hole, with food. Alternatively an animal may "understand" how the task works but, until now, here has been no conclusive proof that animals reason causally when solving complex problems such as the trap-tube.

In this study, six New Caledonian crows were presented with a trap-tube with three arbitrary features inside it.

When the crows were presented with variations of the problem where these features were removed, three of the crows continued to solve the problem, suggesting the crows had not simply learn to pull the treat away from these features.

The scientist then presented the crows with a trap-tube with two holes. One hole allowed food to fall through it and out of the trap, so the bird could eat it. The other hole had a base and so trapped food that was pulled into it.

The three smartest crows failed to consistently solve this problem and appeared reluctant to pull the food into either hole, suggesting they were using the holes to guide their actions.

Finally, the crows were presented with a trap-table problem. In this problem an animal has to choose between pulling food across a wooden table or pulling food into a hole set in the table.

In a recent study 20 individuals from the great ape species were unable to transfer their knowledge from the trap-table and trap-tube or vice versa, despite the fact that both these problems work in the same way.

Strikingly the crows in the University of Auckland study were able to solve the trap-table problem after their experience with the trap-tube. By solving the trap-table the crows demonstrated that they had not just learnt to pull away from the specific hole in the Perspex trap-tube, but could generalise what they understood to a novel problem.

"The crows appeared to solve these complex problems by identifying causal regularities" said Prof Russell Gray of the University of Auckland. "The crows' success with the trap-table suggests that the crows were transferring their causal understanding to this novel problem by analogical reasoning.

However, the crows didn't understand the difference between a hole with a bottom and one without. This suggests the level of cognition here is intermediate between human-like reasoning and associative learning."

"It was very surprising to see the crows solve the trap-table" said Alex Taylor, a PhD student at the University of Auckland. "The trap table was visually different from the trap-tube in its colour, shape and material.

Transfer between these two distinct problems, the trap-tube and trap-table is not predicted by theories of associative learning and is something not even the great apes have so far been able to do".

[By Roger Highfield, Science Editor -- Telegraph UK]

The Crow

Both the House Crow and Jungle Crow are to be found throughout Tiruvannamalai District. As I was sitting in my garden this afternoon I noticed both varieties feeding and generally taking over the area. Since I moved into this house nearly three years ago, I have regularly put food out for birds and animals but it was only about six months ago that the crows started to visit -- which was a pity because as I mention in the below posting both the House and Jungle Crows are great bullies to small ornamental birds.

I became so irritated with the 'Caw Caws,' as I nickname them, that I spoke with several farmers and villagers and also did some serious 'Goggling,' to find out how to deter both kinds of Crows visiting my garden. Well I found the most popular and supposedly 'fool proof' method practised in both India and the West is to kill a crow and hang it in a prominent spot -- meant to work like a charm -- but thought it a little too gruesome so went on to Plan B.

Plan B a local farmer assured me, was equally foolproof and that was to tie black rags in my trees at prominent spots. Well the day after this was done, I sat and waited to see what my regular Crow visitors would do. If ever a bird could look 'startled' -- that is exactly how I would describe the reaction of the visiting Crows. Well the black rags worked for about a day and a half and then the rags lost their dramatic impact, and the Crows happily returned in number.

Next I tried Plan C which was to tie shiny CD-Roms onto tree limbs and let them waive around in the wind. And the Crows actually didn't seem to like that especially on a sunny day (i.e. most days at Tiruvannamalai) when the revolving CDs shimmer and dazzle in the sunlight. Part two of Plan C (which I have yet to do) is to put wind chimes in the trees -- as this supposedly is meant to irritate Crows. We shall see!

In the meantime hope you enjoy the information and photographs I have gathered explaining the difference between two of the most numerous birds in Tiruvannamalai District i.e. the House Crow and the Jungle Crow.

House Crow
The House Crow (Corvus splendens) is a widespread resident of Tiruvannamalai District and can be found all over India except in high altitudes and forests. Its size is about that of a pigeon; around 42 cms with weight ranging between 250-350 gm. The bird has a glossy black plumage, except for its grey collar. Its bill, legs, and feet are black.

There are four geographical races of the House Crow which are based largely on paleness or darkness of the collar. Sexes alike. Its normal call is a harsh The voice is a harsh ‘caaa-caaa’ or a nasal ‘kaan kann’. It reserves its softer calls for resting and during courtship! Its name in Tamil is: Nalla Kaka, Maniyan Kakai

The bird is vocal, gregarious and seemingly unafraid of people. Audacious, cunning and uncannily wary. It is aggressive and will attack and chase off large birds of prey. Breeding pairs will repeatedly dive bomb humans near their nest. This species is able to make use of resources with great flexibility and appears to be associated with humans.

It is perhaps the most familiar bird of Indian towns and villages. It is a highly opportunistic bird and given its omnivorous diet, it can survive on nearly anything that is edible. It feeds largely on human scraps, small reptiles and other animals such as insects and other small invertebrates, eggs, nestlings, grain and fruits. Most food is taken from the ground, but also from trees as opportunity arises.

The House Crow is a useful scavenger but also a great bully and therefore a serious menace to defenseless ornamental bird species in urban areas. It enjoys community roosts in selected trees or groves where large numbers collect very night but is a solitary nester except in areas of high population density.

Its nest is generally a platform of twigs frequently intermixed with iron wire, with cuplike depression lined with tow, coir fibres. And in high density areas, sometimes there are several nests in the same tree. The House Crow will use trees, buildings, or other artificial structures for its rough stick nest lined with coir or other fibre. It lays 4-5 pale blue-green eggs, speckled with brown. Breeding season March through July. Its nest is regularly brood-parasitized by Asian Koel.

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Jungle Crow
The Jungle Crow (Corvus macrorhynchos), or Indian Corby, is a widespread Asian species of Crow. It is highly adaptable and able to survive on a wide range of food sources. This bird has a large bill and due to this it is sometimes called Large-billed Crow or Thick-billed Crow. There are three sub-species within this group with one of them i.e. with Corvus (m.) Culminatus ‘Indian Jungle Crow’ being found in Tiruvannamalai District and other parts of India.

The bird is glossy jet black with a heavy bill and deep and horse ‘caw’. Sexes alike. Singly, pairs or loose parties. It is larger than the House Crow and is found throughout the Indian Union. Local Tamil names for it are Kaka and Kakam.

It is generally found in the countryside, but small numbers are also in towns and villages. The Jungle Crow associates with vultures to feed on carrion and its movements often lead to discovery of large cat kills hidden in the jungle which the bird is quick to locate. The bird is omnivorous, and highly destructive to eggs and chicks of other birds including domestic poultry and young of small mammals.

It has a long bill with the upper one thick and arched, making it look heavy and almost Raven-like. Generally, all forms have dark greyish plumage from the back of the head, neck, shoulders and lower body. Their wings, tail, face and throat are glossy black and the depth of grey shading is almost black. It will take food from the ground or in trees and attempts to eat anything, alive or dead, plant or animal. It is also one of the most persistent species. It is quite bold, especially in urban areas.

The nest is a platform of twigs, usually high up on a tree. There are normally 3-5 eggs. The egg is a broad oval, pointed at the smaller end. The colour is any shade of blue-green, blotched and speckled. In Peninsular India the Jungle Crow breeds from December to April. The nest is built in a fork of a tree, and is a shallow cup of sticks, sometimes neat and well made, sometimes sketchy and ragged; it is lined with grass roots, wool, rags, vegetable fibre, and similar materials. Some nests have been found to be built partly or exclusively of wire. Both sexes share parental duties. Nests frequently parasitized by Koel.

Gregarious at roosts with many thousands at some sites. Large flocks may be seen at dusk arriving at major roosts. The birds’ voice is deeper and more resonant than the House Crow with its usual sound being "caaa-caaa-caaa".