Bouncy balls on an oak leaf? Frans Kapteijns knows more about it!

Forest rider Frans Kapteijns shares his knowledge about nature on the radio every week. Listeners can ask questions at [email protected] This time in Stuifmail, he is aware of a flattened beetle, a mouse in a feed house, snails in an aviary and red acorns.
Profile picture of Peter de Bekker

Every Sunday afternoon there is also a new episode of the Stuifmail podcast. Listen to it here:

Omroep Brabant also broadcasts the television program ‘Op pad’ on Tuesday, where viewers are taken into the nature reserves of Brabant’s Landschap. As a viewer, you can also follow the route from the program yourself. A walking app has been developed especially for the program.

Strange balls under an oak leaf
Ineke Doorn saw a series of strange balls on the underside of a leaf of an oak stem. She wrote along with the photo she sent that she was thinking of a girl. It is true! These balls are called velvet galls or bouncy ball galls. Insects called gray velvet gall wasps, also referred to as oak-hopping gall wasps, develop in these balls. As you can see in the picture, the galls actually look like a bouncing ball with their red and yellow striped appearance. In older galls, the stripes are more visible. The younger galls have more spots or dotted stripes. The wasps of this species grow to about two millimeters in size.

A house mouse on a candy hunt in a food box (photo: Christel van Hirtum).
A house mouse on a candy hunt in a food box (photo: Christel van Hirtum).

Strange ‘bird’ in a feed house
Christel van Hirtum saw a strange ‘bird’ in her feeder. She sent me the picture. What she found there was a house mouse on a candy hunt. This is more common, by the way, because house mice can climb very well, and so they can also enjoy the food placed in such a feeder. House mice belong to the group of true mice and can be recognized by having large round ears, a very long tail and dark eyes. In addition, they are super fast mice and they can jump really well. House mice grow up to ten centimeters in size and have a slender build. The fur varies greatly between brown and grey. The house mouse menu contains everything from bread and cheese to newspapers.

The female of the great woodpecker (photo: Leo van der Pluijm).
The female of the great woodpecker (photo: Leo van der Pluijm).

Strange bird at a feeder
Leo van der Pluijm sent me a photo of a bird enjoying a snack from the food he had hung in a bowl on the fence. He wondered what bird this is. In the picture you see a black and white bird with a strong beak. We are dealing here with the female of the great woodpecker. This black and white bird has a red belly, but the male also has a red spot on the back of his head. The females of the great woodpecker do not have that, and you can see that in the picture of Leo. In the near future we will hear their drumming again, because woodpeckers are resident birds that start the breeding season early.

A bat box (photo: Natuurmonumenten).
A bat box (photo: Natuurmonumenten).

How well do bat boxes work?
Theo de Rover sometimes sees bat boxes and he wonders if these boxes are ever used by bats. Especially since he runs into them in the strangest places. He also wonders if they spend the night there. Certainly not, because bats sleep during the day and not at night. In principle, bats can sleep during the day in these hives and also hibernate. We know this because a lot of research is being done on this, but there is still insufficient research available on which bat box model is best suited for which bat species and for which functions. Nevertheless, bat boxes have been hung up for a long time. The first bat boxes that look like bird boxes were already there in 1863. These boxes were invented by Constantin Wilhelm Lambert Gloger.

The mating of two brown snails (photo: Lieke Dijks).
The mating of two brown snails (photo: Lieke Dijks).

Snails in the aviary, how do I get rid of them?
Ben van der Vorst has many problems with snails in his aviary. Not only in summer, but also in winter. He is now asking me if I have a solution. First of all, it is very important to keep rooms, such as aviaries, as dry as possible. This is because snails prefer to be in moist areas. Another tip: empty the water bowls at night. In addition, you can place coffee grounds or eggshells in the places where snails enter an aviary. What also helps is making sure no food can be found at night. See where they come from, look at the slime trail and put the coffee grounds there. Or place plants in front of the aviary such as thyme, tranny, chives, wild columbine or rock carnation.

Awaiting privacy settings…

Dormus – Natural monuments
The sleeping mouse in the video above belongs to the sleeping mouse. Because the dormouse is an excellent climber and rarely comes to the ground, it is also called a monkey. As its proper name suggests, the dormouse loves hazelnuts. Together with the garden mouse, these are the only two species of dormice that occur in the Netherlands.

Stile-shaped oak acorns that are red inside (photo: Ingrid Wind).
Stile-shaped oak acorns that are red inside (photo: Ingrid Wind).

Why is it that acorns are sometimes red inside?
Ingrid Wind wonders why acorns are sometimes red inside. It has everything to do with the fact that oak trees have a protected substance. It is tannic acid. It has a red color. The tannic acid is also present in the fruits of an oak tree, so the acorn contains the red discoloration. During a hot and very dry summer, the acorns on the tree get less moisture and the tannic acid content present is more noticeable due to the imbalance. Then you see the red discoloration even earlier. In addition, again this year, as in 2018, many acorns fell prematurely due to the drought and were not really ripe. Even then, the tannic acid content in these acorns is higher than in mature acorns.

A dead stinking beetle (photo: Petra Jansen).
A dead stinking beetle (photo: Petra Jansen).

Beaten beetle
Petra Jansen had a strange animal at home. She killed the animal because she was afraid the dog would do something. What she killed is a stink bug. At least that’s what I gather from the photo she sent. You can still see the wings sticking out from under the short carapace, but the beetle used them too late. Usually, these beetles mainly hang around organic waste bins and trash cans, hence the nickname trash monster. If they are discovered, they immediately adopt a threatening stance. They lift their tails, their jaws open and their antennae stick straight out. They look a lot like a scorpion. If the potential enemy is not intimidated by this, they will spray a foul-smelling, milky-white liquid at that enemy. These beetles are also very useful insects, at least if you have a vegetable garden or a garden with many flowers, because they are real snail eaters.

Beautiful pictures
This time a picture from the beautiful Oisterwijk. Frost on Brandven.

Nature tip
Since Saturday, you can go on a nativity scene in Bavel. The third edition will take place until and including 2 January 2023. From five o’clock in the afternoon, the two hundred stables will be illuminated so that they are also clearly visible in the evening.

The Dorpshuis ‘t Klooster on Jack van Gilsplein, in the center of Bavel, has this year been chosen as the starting, resting and ending point for the nativity scene. Dorpshuis ‘t Klooster will be beautifully and festively decorated before, during and after Christmas. You are invited to have a drink or snack here. A comprehensive map with the route is ready for you there.

More information can be found via this link or via this link.

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