If you take the time to look at how most birds walk, such as a chicken or a pigeon, you will notice that they bob their heads. This seems extremely impractical as if we bobbed our heads like that, we would likely become dizzy and vomit quite soon. So why do birds do it and why does it not make them dizzy?
A major difference between birds and human beings is the way our vision works. In humans, our eyes are constantly moving at a rapid rate (saccade) to collate information and stabilise images. Even when we are walking and our head is moving around, our eyes use various sensory information and reflexes to fix our vision at one point, giving us a clear picture. This is such a powerful reflex that one test to check a person’s brainstem function (for example, when they are in a coma) is to move the head and see if the eyes stay fixed on a point or if they follow the head (doll’s eye test). If the brainstem is intact, the eyes will keep looking at a fixed point despite head movement.
Birds on the other hand, cannot fix their vision this way. Instead what they do is they keep their head absolutely still in three-dimensional space when their body is moving. If you hold a chicken in the air and move the body around, you will find that the head stays stationary. This means that when they are walking, the bird’s head will stay still while the body takes a step forwards, then it will move to catch up to the body. From a third person’s point of view, this makes it look like they are bobbing their head, although they are just keeping it very still. In 1978, Dr Barrie J. Frost did an experiment where he put pigeons on a treadmill surrounded by a still backdrop and found that the pigeons did not bob their heads because there was nothing to see.
When children grow up and learn to become independent, parents must let go of their children and allow them to fly free. However, it is the inevitable human condition that the parents will be saddened by this change. For many parents, the moving out of their children can lead to depression and a loss in purpose. This phenomenon has been named empty nest syndrome as it happens as the children leave the metaphorical nest that is home.
As obvious as it sounds, empty nest syndrome can have a serious effect on the parent’s well-being. Common symptoms include depression, loss of purpose, anxiety, stress and a feeling of rejection. The suffering parent continues to obsess whether they brought up their child in a way to prepare them for the big world. At the same time, they feel that they are losing their identity as a “parent” – something they may have defined themselves as while they were bringing up the child. They may also feel rejected as they may believe that the child “does not need them anymore”. It has been observed that mothers are more likely to suffer empty nest syndrome (occasionally, menopause may be a confounding factor). Other factors that contribute are parents who find change difficult, have an unstable relationship with their spouse or those with an unhealthy obsession with their children or with the idea of being a parent.
Empty nest syndrome is a natural part of parenthood, but it is important to know how to prevent it from becoming too severe. The best way to cope with this syndrome is to keep in touch with the children and accept that they are young adults who are moving on with their life. Not only that, but the parents must also recognise that a new era has begun for them as well. This is important as failure to do so will lead to the identity crisis mentioned above. A good way to remedy this is through discovering hobbies and interests while maintaining healthy social networks with other people. Essentially, the parents have to “begin a new life”, just like their children. It is also worth noting that it helps if the children recognise this as well and try to keep in touch with their parents to make sure they are coping well without them.
An airplane flying across the sky faces many dangers. But a very common yet not well-known type of accident is the bird strike. Just as the name suggests, a bird strike is when a plane collides with a flying bird. This may not sound so dangerous, but considering a plane typically flies at 800~900km/h, the energy from the collision is quite significant. If a plane flying at 800km/h collides with a 5kg bird, the energy generated is 92 tonnes. This is not only enough to instantly kill the bird, but also enough to damage the plane.
The most common type of bird strikes is when a bird collides head-on with the windshield or gets sucked into the engine. The latter can cause severe damage to the engine and even cause it to fail. For example, in 1960 a plane flying above Boston collided with a flock of starlings, leading to all four of its engines failing and causing it to crash, killing 62 passengers. Since birds typically fly below an altitude of 9000m, bird strikes most often occur during take-off and landing. However, there are case reports of much higher altitude crashes, with the record being held at 11300m.
According to statistics, the most common type of bird involved are waterfowls and gulls, with 15% of bird strikes being severe. Bird strikes cause $1.2 billion worth of damage annually worldwide and has cost 200 lives since 1988. The first bird strike occurred with the invention of the airplane, as recorded by the Wright brothers (inventors of the modern airplane). As bird strikes cause so much damage, airports place many countermeasures to prevent them. The most frequently used methods are driving away birds from runways by using scarecrows and other methods, or modifying the plane and engines to be more bird-resistant.
Alex (Avian Language EXperiment) was the name of an animal psychology experiment that ran for 30 years starting from 1977. The experiment was designed to see if birds could undertake complex problem solving and learn languages like primates. For this, Dr Irene Pepperberg bough an African grey parrot, named him Alex and started teaching him how to speak. Before Alex, scientists believed that animals needed a large enough brain like a primate to handle the complex problems related to language. But Alex proved otherwise.
Before Dr Pepperberg, scientists failed to establish any two-way communication with parrots. She used a new training technique called the model/rival technique, where two trainers act in front of the parrot to teach it things. The method is as follows. One trainer (the rival) shows the other trainer the desired student behaviour they want the parrot to learn. The other trainer then compliments the trainer and shows attention. The parrot sees that the behaviour gets the trainer’s attention and learns it to compete with the rival. This technique was extremely successful and Alex began picking up words at a very fast rate (technically it was more of a two-way communications code than “language”).
Once communication was possible, Dr Pepperberg taught Alex many different concepts. Over the course of his life, Alex learnt 150 words, how to differentiate between seven colours and five shapes and also understood the concept of numbers and sizes. If you showed Alex two objects, he could answer many questions regarding one object (thus showing that his response was not a conditioned one). For example, if you showed him a small blue key and a large green key, he could answer what colour the larger key was, or which one was the green key. Furthermore, if a plate full of objects of different colours and shapes was presented to him, he could correctly count how many green blocks (or any other shape or colour) there was among the objects. The important point here is that he could pick out just the green blocks, excluding green balls or blue blocks from his answers (showing he fully understood the question and could attribute more than one characteristic to one object). He knew how to express himself, such as saying “Wanna go back” when he was tired, and would give playful, incorrect answers when bored of the repetitious experiments. According to Dr Pepperberg, Alex had the intelligence equal to a dolphin, a great ape or a five year-old child. He also knew how to attain knowledge by asking questions, such as when he asked what colour he was to learn the word “grey”.
Alex, who told us so much about the intelligence of a parrot, unfortunately died in 2007. The night before he died, he said the following last words to Dr Pepperberg: “You be good. I love you”.
The northern white-faced owl, found in the Sahara Desert of Africa, is a small, cute bird of about 22~24cm length. It is famous for a very unique defence mechanism. As shown in the photo, it normally has a round, puffy appearance, but when faced with a fearsome predator like a hawk, it undergoes a drastic transformation. The owl shrinks itself as much as possible to avoid the enemy’s attention, while looking like a sick bird that has lost a lot of weight. This appearance gives the predator the impression that the owl is not worth the effort of hunting and lowers the chance of it attacking. The ability to shrink to half its original width is achieved through elongating its body and pulling in its feathers as much as possible. Also, when assuming this shape, the owl always faces the predator and poses at an angle to minimise its exposure.
This transformation is only seen when the owl is placed in front of a large predator like a hawk or a much larger owl. When in front of a similarly-sized owl, it exhibits a different transformation where it flares up its wings to make itself look much larger, intimidating the opposition. But this behaviour is common in many other species of owls, whereas the shrinking performance is a rare behaviour only seen in the northern white-faced owl.
When asked “name a bird you see often”, most city-dwellers would name a pigeon or a sparrow. These two birds are the most famous urban birds that are closely associated to humans. The sparrow, being very opportunistic and adaptable, have easily taken over environments around the globe, especially those where European settlements were made. Nowadays, they are regarded as a pest due to their foraging of agricultural crop and the spread of disease. However, citizens still view them in a positive light, especially in parks or gardens where the sparrows appear to be a “symbol of nature” (ironically, they are likely an invading species driving away native birds).
One interesting fact regarding sparrows that most people do not seem to know is how to differentiate a male and female sparrow. A female sparrow has very soft, brown feathers, with no marked features. A male sparrow has areas of dark brown or black feathers, especially on the head and eyes. Its beak is also darker than the female. If one observes carefully at sparrows, they can notice that the two behave slightly differently as well.