Archive for the ‘Birds’ Category

Jan
19
2010

Clever as a crow

The New Caledonian Crow has impressive abilities when it comes to solving a problem, and finding the right tool for the job.

In past experiments these crows have figured out how to use tools, such as hooks to retrieve food, and have even made tools by bending pieces of metal when ready-made hooks weren’t available. But in a recent study, the crows have solved a more complicated puzzle where they had to use a series of tools in the correct order.

In this test, they were presented with four horizontal transparent tubes. One tube contained the prize – a treat that was visible to the crow but completely out of reach. The other tubes contained hooked sticks of increasing length – which were also out of reach. One small hooked stick lay in the test area, with which the the crow could make a start on the tricky puzzle of getting to the treat.

Absolutely independently the crow worked out that she needed to use the smallest tool to extract the medium-size one, then the medium-size one to extract the longest tool, which she was finally able to use to reach the treat.


 

Now researchers at the University of Oxford have observed New Caledonian Crows using tools in their natural environment. The crows use tools for many purposes such as fishing out beetle larvae from dead wood. It has even been shown that they use tools more often than their beaks for some tasks. Like their laboratory counterparts, wild crows appear to be able to match the right tool to the job using longer tools for deeper holes and preferring to select leaf stems over twigs.  Adult crows were more adept at using tools, suggesting they have the ability to learn and to improve their techniques over time.

Sources

1.Bluff, L.A., Troscianko, A., Weir, A.S., Kacelnik, A., Rutz, C. (2010)  Tool use by wild New Caledonian crows at natural foraging sites. Proceedings of the Royal Society B. doi: 10.1098/rspb.2009.1953

2. Behavioural Ecology Research Group at Oxford University

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Jun
27
2009

Rooks are no rookies when it comes to using tools

Apes, crows and dolphins have been seen to make and use tools. Now, captive rooks have joined the band of animals who are “tool users.”

Rooks have not been seen to use tools in the wild. But not only can they use tools, they can use two in succession and they can make new ones. This BBC article reports research in which the rooks worked out how to get a food treat from a apparatus consisting of a tube and a small trap door. They needed to choose a suitable stone and drop it into a tube to release the trap door and get their treat. They chose the heaviest stone as the most likely to be weighty enough to make the trap door open. They also  had to choose from different-shaped stones, not all of which would fit into the tube. They chose the best-shaped stone! Here’s the film of the clever rooks with rocks.

Rooks are even more clever than we thought. Photo: foxypar4

Rooks are even more clever than we thought. Photo: foxypar4

The birds also quickly learnt how to bend a straight piece of wire to make a hook, so they could pull up a small container with food in it from the bottom of a test tube. It is amazing to see! Watch the film clip.

Betty, a captive New Caledonian crow, was the only captive bird who had previously been seen to do this. Crows in the wild do use tools, such as twigs and leaves. They use their beaks to make these tools into a satisfactory shape and then pick up ants and other insects. They also use grass stems. The rooks showed they can use and make tools too; three out of four made a hook in their first trial. One of the researchers pointed out: “The study shows the creativity and insight that rooks have when they solve problems.”

Rooks also understand that they can work in pairs to get a good food source. In this experiment, also reported by the BBC, researchers put two hooks on a small tray which had treats for the rooks, and then put a length of string through the hooks. The rooks were in an enclosure and the tray was just out of their reach. To pull the tray to them and get the food, each rook needed to pull on the strings at either side of the tray. The rooks all worked this out – some immediately and others took a bit longer. The rooks’ understanding of this “need for team work” is said to be as good as that of chimpanzees. Here’s the film clip of the dexterous rooks.

Rooks and crows are both in the corvid family, along with jackdaws, jays, magpies and ravens.  These birds have long had a reputation for being clever and researcher Nathan Bird at the University of Cambridge said: “I would rate corvids as being as intelligent as primates in many ways.”

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May
26
2009

Mockingbirds can place your face

Mockingbirds can quickly recognise individual humans who seem to be a threat to their nest. After only a short time, the birds recognise someone who has bothered them and make big efforts to drive them away. But they ignore other passers-by or nearby strangers.

This research took place at the University of Florida, where Professor Doug Levey, a zoologist, is reported as saying:

Mockingbirds can quickly learn to recognise individuals

Mockingbirds can quickly learn to recognise individuals

“We don’t know whether it’s unique to mockingbirds, but it does suggest these birds are a heck of a lot more intelligent than people have ever given them credit for. People have known for a long time that crows and parrots for example have a lot of intelligence. But these birds are fairly small. … It’ll change the way people view the intelligence of birds like this.”
The mockingbirds live in what is considered to be a natural environment, and researchers say their scientific paper will be the first published research to show that “wild animals living in their natural settings recognize individuals of other species.”

These clever birds show us yet again that we need to respect animals’ abilities when human actions affect their lives.

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Mar
13
2009

Breakfast is important

Western scrub-jays hide food, such as acorns, to eat later – called ‘caching’. Previously scientists have thought that the jays did this only on instinct and that there wasn’t much planning involved.  

Scientists had thought that only humans can plan for their future needs in a detailed way, but research seems to show that some birds can also think about storing food for the future.

In one experiment, each bird was kept in a cage which could be divided up. To start with, the birds were given only powdered food, which they couldn’t cache. Then in the morning, they were confined either to an area of the cage where they were not given breakfast – the ‘no breakfast’ area; or in an area where they were given something to eat – the ‘breakfast’ area.

Given the first chance to cache whole pine nuts in the ‘no breakfast’ and ‘breakfast’ areas of the cage, the jays cached three times more pine nuts in the ‘no breakfast’ area than in the ‘breakfast’ area.

Jays can make future plans

Jays can make future plans

This seems to show that they understood there might be no food given to them the following morning and so they tried to ensure they’d have something to eat.

Jays choose a varied diet
In a second experiment, the birds were initially fed only powdered dog biscuits for breakfast in one area, and powdered peanuts in another. After a few days, the jays were given whole peanuts and whole dog biscuits in the evening, with the chance to cache them in the ‘breakfast’ areas.

The jays took this first chance to cache both types of food in each breakfast area, putting peanuts as well as dog biscuits in the area where they were usually only given dog biscuits, and vice versa. This may indicate that not only can the jays plan for the future, they also need variety. 

Professor Nicky Clayton said, “The western scrub-jays demonstrate behaviour that shows they are concerned both about guarding against food shortages and maximising the variety of their diets in the future. It suggests they have advanced and complex thought processes as they have a sophisticated concept of past, present and future, and factor this into their planning.”

Earlier experiments had showed that scrub-jays could remember when and where they saved food, and which type of food they had saved.  This is called ‘episodic-like’ memory, and was also previously thought to exist only in humans.

Jays are members of the crow family. People through history have considered that crows are intelligent, and these findings appear to back that up.

The Cornell Lab of Ornithology also tells us this interesting research snippet about jays’ abilities: “Jays that had stolen the caches of other jays noticed if other jays were watching them hide food. If they had been observed, they would dig up and hide their food again. Jays that had never stolen food did not pay any attention to whether other jays were watching them hide their food.” 
  
The natural habitat of western scrub-jays is the west of the USA in areas of stunted trees – known as ’scrub’ – and they also now live near surburban areas.

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