Hawks flying silently, eagles kicking snakes—The hidden ingenuity and passion of Kakegawa Kachoen seen on 'The Backyard' (Former professor, 776th day of retirement)

To a morning that begins with the sound of birds

It is now mid-May, and it has suddenly become hot. Lately, I cannot help but feel that spring and autumn are gradually getting shorter. Fortunately, perhaps because there is a lot of greenery around my house, spring is still somehow lingering. The mornings, in particular, are a comfortable time when a cool breeze blows through. For several days now, I have been woken up by the songs of small birds in the early morning. Yesterday morning, I even heard the call of a cuckoo. However, I will only be able to enjoy this for a little while longer. Next month, the great chorus of the Kumazemi cicadas will suddenly begin. While I can wake up peacefully to the sound of small birds, the cicadas start chirping around 5:30 in the morning, louder than an alarm clock. It is noisy beyond compare. I would like to enjoy the sound of the birds for a little while longer.

Behind the scenes of 'Kakegawa Kachoen' as seen on 'The Backyard'

With that in mind, this time I would like to cover the special feature on 'Kakegawa Kachoen' that I watched on NHK's 'The Backyard.' This bird and flower park is a theme park centered on 'interaction between flowers and birds,' visited by about 350,000 people annually. It is known not only as a tourist facility but also as a base for breeding rare bird species, passing on advanced horticultural techniques, and disseminating unique information. The program showed us not only the inside of the park but also the backyard in quite some detail, making for a very enjoyable time. (Please also see the title photo and the photo below: Note 1)

'Mandarin duck couple'—a myth? The realistic love lives of birds

About 600 birds of approximately 100 species live in the park, and you can observe their wild ecology and the unique characteristics of each individual up close. The first 'behind-the-scenes' story introduced by the deputy director was about the 'actual ecology of mandarin ducks' (photo above, bottom row). Generally, mandarin ducks are called 'mandarin duck couples' because the male and female are always seen snuggling together. This term is often used in the entertainment industry and elsewhere to describe a happily married couple. However, according to the director, the reality seems to be a little different. Mandarin ducks may change partners every year, and they are also known to cheat. Therefore, for those who know their ecology well, the expression 'mandarin duck couple' is not necessarily a compliment (laughs).

The secret to why hawks can fly silently

Personally, the part I enjoyed the most this time was the birds of prey corner. First, the flight characteristics of hawks were introduced. To hunt without being noticed by their prey, hawks fly very quietly and at low altitudes. In fact, when a guest was sitting facing backward, a hawk approached in a low-altitude flight and passed right by them, yet it was so quiet that they did not even notice. The guests were surprised by the sight of it flying truly without a sound. By the way, the hawk that appeared this time was a species called the 'common buzzard' (nosuri). Its name in Japanese is said to mean flying so low that it 'grazes the ground.'

So, why can large hawks fly agilely and silently? The secret was in their feathers. The 'flight feathers' that spread out when the wings are opened are said to be important. The feathers are shaped like tree leaves and have a core in the middle. By hollowing out the inside while maintaining the structure, they are both strong and light. In this way, birds that hunt have acquired wing shapes and movements that allow them to fly silently. On the other hand, prey animals like pigeons need to flap their wings quickly to escape, which is why their wingbeats are loud. (Please also see the photo below)

The deadly kick of the secretarybird

The program also introduced a slightly unusual bird of prey: the secretarybird. First of all, its appearance is quite different from other birds of prey. It has long legs like a flamingo or a crane, and while it can certainly fly, it sometimes walks 20 to 30 km a day to move around. Looking at the footage, it runs quite fast, and it might be a little scary if it were nearby. What was particularly interesting about this bird was its unique hunting method. In the program, they showed us this using a toy snake. The secretarybird uses its long legs to kick the snake repeatedly to attack it. Moreover, it does not just kick blindly; it aims accurately at the head, which is the vital point. It seems they understand which parts of the body will effectively weaken their opponent. The movement of swinging down its long legs is very dynamic, and I would like to see it in person at least once. (Please also see the photo below)

From GPS attachment to claw and beak care—The front lines of bird health management

The introduction to the backyard also provided a detailed explanation of the safety and health management of the birds. Birds that perform in outdoor shows were equipped with GPS in case they were blown away by the wind or went too far. This allows the staff to track the birds' locations and go retrieve them. There were also meticulous efforts made for daily health management. For example, if a bird stays in the same spot for too long, it can develop bumblefoot, which is like a callus on the sole of its foot. To prevent this, the perches were made of a prickly material to ensure that the bird's weight was not concentrated in one spot. Additionally, to prevent their claws from growing too long and injuring themselves, or their lower beaks from growing too long and making it difficult to eat, the birds were safely restrained and their claws and beaks were regularly trimmed to the appropriate length. (Please see the photo below as well)

A paradise in full bloom all year round, supported by an automatic irrigation system

Another star of Kakegawa Kachoen is the plants, which are kept in full bloom all year round inside the all-weather glass house. In this space, while the birds fly freely, maintaining the plants in a healthy state requires highly sophisticated management techniques. For example, there is the three-dimensional display of impatiens, which could be called the symbol of the park. Like a natural chandelier, pots hung from the ceiling filled the entire space with color. This is kept in full bloom all year round by an automatic irrigation system in the backyard. (Please see the photo below as well)

This automatic irrigation system operates using a precise mechanism that utilizes unglazed ceramic sensors and capillary action (photo above). Countless pots hanging from the ceiling each have a tube running down from above, with an automatic irrigation device connected to each pot. An 'unglazed' component that detects soil dryness is attached to the tip of the device. When the soil in the pot dries out, water inside the unglazed sensor is drawn toward the soil through capillary action. As water exits, the water level inside the device drops, and the internal pressure decreases. This drop in pressure triggers the valve to open, and water is supplied drop by drop, like an IV drip. Furthermore, when sufficient water has been supplied and the soil reaches the appropriate level of moisture, the water supply stops automatically. The greatest advantage of this mechanism is that it prevents overwatering while maintaining the optimal amount of moisture for the plants at all times.

Kakegawa Kachoen was a fascinating facility where visitors could interact with birds and flowers up close. However, behind the scenes, there were professional and meticulous efforts accumulated, such as ingenuity to maintain the birds' wild abilities, safety management using GPS, delicate health management like claw and beak care, and an automatic irrigation system to maintain the beauty of the plants. Also, the background to gaining enthusiastic fans seems to be their unique information dissemination, such as the book 'Kakegawa Kachoen Bird Incident Report' by the breeding staff. It is said that it introduces affectionate daily episodes that only the staff can tell, such as a 'ranking of how painful it is to be bitten by a bird' and rare incidents, which sounds fun.

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Note 1: From the NHK 'The Backyard' special feature 'Kakegawa Kachoen'