Tag Archives: Birds

Did you know that jays fall for magic tricks and don’t always like it?

Eurasian jay

Some time ago, a video of an orangutan vividly reacting to a disappearing fruit trick circulated on the internet.

Besides collecting YouTube likes, showing magic tricks to animals can also help to understand animals’ cognitive processes and their perception of the world.

Recently, scientists studied how Eurasian jays (Garrulus glandarius) react to magic tricks and unfulfilled expectations. Jays are corvids – a group of birds known for their highly developed cognitive skills. They even use tricks themselves – when they know they are being watched, they act as if they are hiding food in many places, but only truly do so in some, cleverly manipulating the food with their beak.

Recently, scientists showed jays a trick in which they pretended to insert a treat in one of two plastic cups, but actually hid the treat in their hand, just as a magician would do when trying to fool people. They then turned both cups upside down and the bird could turn them over to get the treat. The trick was that beforehand, the scientists had already put a treat into the chosen cup, either of the same kind as they showed the jay, or a different one. If they put in a different one, it could be either more or less desirable to the particular jay than the shown treat.

The trick of ‘swapping’ food. Diagram from the original article

The jays consistently picked up the cup into which the scientist ‘inserted’ the food, but reacted differently depending on what they expected and what they found. If the birds found the same treat that they ‘saw’ being placed in the cup, they just ate it quickly, regardless of whether it was their favourite treat or not. However, if the bird found a better treat under the cup than the one the human showed to it, it took a little longer to eat it and sometimes the jay would look into the cup as if to check where the expected food was. However, the most dramatic reaction occurred when the bird expected a favourite treat but found an inferior one. Then it often checked the cup again, looked under the other one and in about half of the cases did not eat the food at all (even if it would normally eat this treat when it was expecting it).

This strong reaction to an unpleasant surprise is similar to how humans react when they lose something. No one likes it if they are promised something but they don’t get it. And just like in humans, those jays that were more dominant showed stronger dissatisfaction – they were more likely to reject food that was worse than they expected.

I am curious to see what future experiments using magic tricks will teach us about animals.

If you want to see recordings from this experiment, click here.

Jay photo by Steffi Wacker from Pexels.

Did you know that birds use cigarette butts to fight parasites?

Male house sparrow

Recently I took part in a cleaning action in my village. It was actually already rather clean, and we found little rubbish on the streets and sidewalks. However, about two out of three pieces of garbage were cigarette butts. This reminded me that some birds living in cities use those remains of smoked cigarettes to line their nests. Why do they do that?

More cigarettes – less parasites

Research conducted in Mexico City on house sparrows and house finches shows that there were fewer parasites in nests that contained more cigarette material. Adult birds and chicks are vulnerable to attacks by parasites such as ticks, mites and fleas, which not only suck blood but also spread disease.  The filters of smoked cigarettes are saturated with nicotine, which tobacco plants produce to fight small herbivores. Nicotine and other toxic substances in cigarettes repel or even kill parasites. Nests with more cigarette material had better hatching success and chick growth and survival rate.

Cigarette treatment

However, do the birds use butts specifically for their medicinal purposes, or simply for insulation, and their anti-parasitic effect is just a bonus? To test this, scientists replaced the original nest lining of house finches with an artificial one – either without parasites or with added live or dead ticks. The birds that got live ticks added more cigarette butts to their nest than birds from other groups. This show that birds use cigarette butts in response to parasites as a way of self-medication.

There is no such a thing as a free cigarette

However, we know that cigarettes are harmful to human health. They contain nicotine and other toxic substances. Are they not harmful to the birds? Unfortunately, it seems they are. Birds with more cigarette material in the nest have more DNA damage, which can lead to cancer (although a direct link between cigarette use and cancer in birds was not investigated). More DNA damage occurs in both the chicks and their parents – especially the ones that spend more time building the nest or incubating the eggs.

Adding cigarette butts to nests seems to be birds’ adaptation to city life – the use of human waste for self-medication. However, we still do not know if the short-term benefits outweigh the long-term costs. Therefore, smokers have no excuse to throw their cigarette butts on the street.

Photo: JrPol, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=40108812

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Did you know how smart chickens are?

When I was a child, I often went to visit my grandmother in the countryside. She had a small flock of chickens that freely roamed the front yard. At that time, I was mostly interested in exotic animals and paid little attention to the chickens. But now I regret that I didn’t observe their behaviour more, as chickens’ cognitive skills are more advanced than many people think.

Logical inference

Wild and free-range chickens live in groups with a hierarchical social structure. There is one dominant rooster and a dominant hen, subordinates of both sexes and chicks. The subordinates are not all equal, but form a so-called pecking order. Chickens can peck others who are lower in the hierarchy without fear of retaliation. If a new chicken is added to the group it has to find its place in the pecking order. But that does not mean that it has to fight each other chicken. Chickens watch each other’s fights and can draw conclusions from the results.

For example, if a new chicken beat a chicken that is dominant over the observer, the observer should avoid fights with the new chicken (if the new one is stronger than the dominant one, then the new one must be stronger than the observer). But if the new chicken lost to the dominant, then it might be worth it to attack the new chicken as there is a chance of winning. Chicken behaviour seems to indeed follow this logic. It is an example of self-assessment combined with transitive interference – a reasoning ability that humans develop only at the age of seven.

Numerical abilities

Even a few days old chicks can count, add and subtract (at least up to five). For example, in one experiment researchers showed chicks two sets of balls and then hid them behind two opaque screens. Afterwards they moved the balls between the screens, one ball at the time, while the chicks watched it. Afterwards chicks were able to indicate the screen behind which more balls were hidden.


When given the choice between two keys to peck, one of which gave brief access to food after a brief delay, and one of which gave much longer access to food after a longer delay, hens preferred the second option. Therefore, they were willing to wait a longer time for a greater reward.  In other words, chicken pass a kind of marshmallow test for self-control!

Communication and manipulation

I wrote some time ago about hens paying attention to great tit alarm calls. But chickens of course also listen to each other. They can adjust their calls to a specific situation and they can even cheat.

Roosters give one alarm call when they spot a bird of prey and a different one for a terrestrial predator (for example a raccoon). And hens react appropriately to each call and situation. When the rooster is in a safe place (for example under the cover of bushes), it will call longer. It seems to understand that it is safe from the predator.

Roosters also have a specific call and behavioural display they use to notify hens when they find tasty food, in order to increases their mating chances.  However, if a subordinate rooster finds food when a dominant rooster is nearby, it will only perform the display and omit the call, reducing the risk that the dominant rooster will notice him and chase him away. But when the dominant rooster is distracted by something else, subordinate roosters will also call.

Sometimes a rooster cheats and calls even if he doesn’t find food, but hens quickly learn not to trust this male.

Personality and its consequences

Like many other species that have been studied, chickens have personalities.

Some hens tend to be more nervous than others, which in turn affect their chicks’ stress level. Roosters’ personalities can affect result of a fight. If two roosters of the same size fight, the outcome can be predicted by studying their typical behaviour: usually the bolder, more active, more explorative and more vigilant individual wins.

These are just some examples of chickens’ cognitive abilities. Additionally, they have time perception, episodic memory, emotions and other skills often attributed to “more advanced” animals. They are much more than just “machines” for egg and meat production.

If you have a chance to observe (relatively) free-range chickens, take the opportunity to have a closer look at their behaviour. And if you want, let me know what you saw.

Photo: Quang Nguyen Vinh, Pexels.com

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Did you know that chickens listen to great tits?

Naked Neck hens and a great tit (small insert)

Maybe you are familiar with this situation: a group of crows is searching for food in a meadow. Suddenly one of them gives an alarm call and all birds fly off.

When animals live in groups often one of the group members will warn the others when it detects danger. Additionally, wild animals often react to alarm calls of other species, especially if they have common predators.

Domesticated animals also warn members of their group about danger. Free-range chickens behave appropriately when another chicken gives an alarm call. But do they react to alarm calls of wild birds? This is a valid question since, first of all, chickens were bred for hundreds of years for their meat or egg laying rather than survival skills. Secondly, most of the time humans provided at least some protection against predators. And lastly, unfortunately, in recent decades most of the chickens lived (and still live) indoors, completely isolated from nature and any predation besides humans.

Recently scientists decided to check if chickens respond to alarm call of wild birds, and specifically great tits. These bird species are both preyed upon by for example buzzards and goshawks. Researchers installed speakers on a free-range farm of Naked Neck chickens in France and played recordings of either great tits’ alarm calls or of their songs.

For the majority of the time hearing great tit alarm calls, the chickens were vigilant – they kept an erect posture and scanned their surroundings. When great tit songs were played the chickens spent less than half of the time vigilant.

At this moment it is unclear whether the response to alarm calls is instinctive or learned. However, if you plan to open a free-range chicken farm, it may be profitable to do it somewhere where many song birds live, even if they sometimes steal some chicken food.

Photos: Great tit – Petr Ganaj from Pexels.com; Naked Neck chickens – Simone Ramella from Rome, Italy – Corte Cecina, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=3830746

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Did you know that birds can plan their next day’s breakfast?

A western scrub-jay

Many people think that only humans know about and plan for the future. They see animal behaviour that is useful for the future, like squirrels hiding nuts in autumn, as innate (instinctive). However, experiments show that animals can plan also in situations they would never experience in the wild.

For example, the western scrub-jays (North American birds related to crows) can plan ahead as far as their next day’s breakfast.

The experiments (which I will explain below) may seem complicated, but that’s precisely the point, to force the birds to use their cognitive abilities and not act instinctively. And I invite you to imagine you are a scrub-jay and play along as though you were taking part in the experiment.

Each bird was housed in a room that was divided into three compartments (see illustration below). The middle part was available the whole time. Every morning only one of the side compartments (kitchens) was opened, with each kitchen available every second day. In kitchen 1 there was always breakfast waiting, but in kitchen 2 there was never anything to eat. Therefore, every second day, the jays were hungry in the morning. A few hours later the other kitchen was also opened. From then, the food was freely available until evening.

Scrub-jays are famous for caching (hiding) food for later, but during most of the experiment they only got powdered peanuts that there were not able to cache.

After six days, after the birds had gotten used to the situation, they were given whole nuts in the evening, which they could store in ice-cube trays filled with corn cob placed in both kitchens.

If you were a western scrub-jay, where would you hide the food?

The birds hid most of the nuts in the same place that I expect most people would   – in the breakfast-free kitchen.

So, maybe they cached the food because they just love doing so, and did it in the place in which they experienced hunger (some other animals are known to do that) and it was just an instinctive behaviour?

A second experiment gives a strong indication that the western scrub-jays actually planned their breakfast. The basic setup of the experiment was the same, but now one kitchen provided powdered nuts and the other powdered dry dog food (this may sound weird but these birds like both types of food). On the evening of the sixth day, they got whole nuts and dog kibble.

What did the birds do? They hid more nuts in the “dog-food kitchen” and more dog food in the “nuts kitchen”. This way they had a multiple breakfast options, no matter which kitchen was open.

Not only humans like a varied breakfast, and can plan ahead to ensure it!

Experimental cage

Western scrub-jay’s photo from Msulis at English Wikipedia. – Transferred from en.wikipedia to Commons by Common Good using CommonsHelper., CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=6658580


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Did you know that great tits are conformists and can form traditions?

Probably everyone in Europe is familiar with this little bird – great tit. And the winter is a great period to observe them as they often come to birdfeeders in gardens and on balconies. They usually come in pairs or small groups.

It is known that these birds are innovative but they can also learn from each other and they seem to follow the behaviour of majority of a population (group of birds that live in one area). Therefore, showing conformity.

At least when it comes to opening puzzle boxes. A few years ago, researchers in the UK trained a couple of wild great tits from different locations to open a puzzle box by either sliding its door to the left or to the right (one bird learned only one method)*.

Then they released them into the wild and provided puzzle boxes filled with mealworms (a delicacy for the great tits) that could open either way (both to the left and to the right).

Within 20 day most of the birds knew how to open the boxes and it seems that they learned it from the trained individuals, as in populations without trained birds much fewer individuals managed to get to the worms.

But what is more interesting, most of the birds in a given area used the method that was used by the trained bird (left or right slide) even if the other way was equally difficult and rewarding. This shows social learning from others.

But here comes even a more amazing finding. There were birds that actually used both ways of opening the box (some probably learned the less common variant individually, by trial and error). However, most of these individuals still preferred the most common behaviour. And some of them even switched from the less common to more common behaviour. But never the other way round.

If immigrant birds came from areas with different traditions, most of them changed their behaviour to match the locals (A reader who is themselves an immigrant will probably understand this).

When researchers returned the next year, they saw that the local traditions were even more pronounced, with fewer birds using uncommon method to open the box.

All these observations show that not only humans follow societal norms and have traditions (group-specific, socially learned, and often arbitrary behaviour) that they learn through conformism.

Although, like in human populations, there were still few birds that did not follow societal norms and just slid that door against local tradition.

* How do you train the bird to open the box the way you want? Well, block the door so it can open in only one way. The training part is quite simple (in case you want to train your own pets – please do not capture wild birds!). First show the birds an open box with worms inside that they can just pick up. Then, each time close the door more and more until the birds can reliably open it even if it’s fully closed (great tits learned that in 4 days).

Photo of great tit by Petr Ganaj from Pexels.com

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