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Our winged workers... At the table!

Updated: Jan 10, 2022

Bloodsucker, aggressive with man, carrier of diseases... for one; remarkable acrobat, zinging its clear and fluid song at the season of love, adorable flag-bearer of the colours of the summer... for the other. Each one has its reputation but the bat and the blue tit both bring us a precious help.

At night!

Because of its phalanges connected by a membrane, it is known as chiroptera which in Greek means "flies with the hands". There are 1,200 species of bats out of the 6,500 species of mammals in the world. It is the only mammal to be capable of active flight. The characteristics of each species are quite different. The smallest of them are less than your thumb, the largest approach 1.70 m. Each species has its own call. Most of them prefer the night, but others prefer the day. Some feed on fruits, others on amphibians, others on small mammals or for some, only on the blood of large mammals (including man!) that they wound with their sharp teeth and then lick the blood that comes out of the wound with their anticoagulant saliva. Their bad reputation is not to be made any more.

At home, one of the smallest is the most often encountered and it contributes to the balance of our gardens. Here, it is not a question of blood-drinking bats; the pipistrelle feeds only on insects, like the 31 species listed in France. It is synanthropic, i.e., close to humans and adapts to our cities as well as to our countryside. Its species is thus threatened because of a habitat often little visible and thus destroyed during renovations or gardening. From its first autumn, the male attracts females to its mating site by singing during its outings; a harem of about ten females is then created. The females and males hibernate in a mixed colony until the beginning of spring, some of them more than 30 000 individuals. The spermatozoa living 6 months, the females begin their gestation in early April, after hibernation. They then separate from the males and settle in maternity cottages. They will give birth 1 month and 1/2 later to 1 baby pipistrelle most often and will leave once the young became autonomous.

These small bats, greedy for our insects, each feed on nearly 3,000 insects per night and are thus particularly useful in "cleaning" the vineyards.

Studies by the CIVB (Conseil Interprofessionnel des Vins de Bordeaux) have shown that the presence of pipistrelle bats reduces the population of butterflies by up to 4 times. And even when they have a large choice of food, they are still content to hunt their favourite insect.

So, we work to accommodate them by providing them with food and shelter throughout the year. Our barns, workshops and fallow areas participate in the long-term conservation of the species by allowing the installation of colonies, our 10 nesting boxes distributed in our vineyards throughout the estate take over for the mothers and their toddlers by offering them a nesting place. These shelters meet their specific needs: installed in height, entry from below, opening less than 2 cm wide, possibility of hanging inside, far from noises and lights... They can therefore go about their business each night in complete serenity. They deserve it!

As by day!

The blue tit is a small bird of 10 to 12 cm, a little chubby, that everyone has already been able to observe in his garden or in a park so much he got used to our presence. It is recognizable with its head and its back of colour... blue, its belly of yellow colour related to the carotenoids present in great quantities in its preferred larva and its black tie. It is cavernicole and likes to live in cavities, even close to humans.

During the breeding season, the blue tit is essentially an insectivore and eats up to 500 insects per day; spiders and larvae are its favourite foods.

When it comes to hunting, it is extremely agile, and plays the acrobats suspended by swinging from branch to branch.

Blue tits are monogamous, and mother and father raise their 1 to 2 clutches of the year of 7 to 13 eggs together. Everyone will fledge when the chicks can fend for themselves, about 2 months after birth.

At the end of autumn and in winter, when the insects become rarer or disappear, the blue tit has two possibilities: dominant bird, it will know how to take what is at its disposal and will become sedentary, its diet will change and will be composed of seeds and the few late insects. We like it! Or it will migrate to less hostile lands and rich in insects.

As for the bats, we installed blue tit houses which can be used as nesting places. This small hut was not built at random, but to meet the requirements of the whole family. To facilitate their arrival and to push back the intruders, the diameter of the hole of flight is 28 mm; the selection is made at the door! The great tit, for example, prefers the 30 mm opening. In its cosy nest, the blue tit requires a ceiling height of 23 cm and a living space of 13 cm². It is done, in the 6 nesting boxes skillfully distributed on the vineyard in order to avoid the quarrels of neighbourhood...

We do not force the arrival of Pipistrelles bats or blue tits; too many of them would influence the biodiversity of the domain, which we want to be as multiple as possible. Each one has his role, each one at his post! Nevertheless, we do not use insecticides on our vines, so their presence is welcome to participate in the cleaning of our plots, 24 hours a day!

Sources: Guide Delachaux Les Chauves-souris d’Europe, Office National des Forêts, Géo le magazine,, Les Cahiers Techniques du CIVB, LPO, SFEPM, (schéma nichoir mésange bleue), Fledermausbrett (nichoir à chauve-souris)

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