September 2016

Photos Arne Ader

Translation Liis

Maple leaf

Calendar autumn started at 17.21 on September 22

We will see whether there will be time for anthocyanins to be created in the leaves, to colour the leaves beautifully red?

Or will the yellow and orange carotenoids remain dominant in the tree crowns – colours that were present in the leaves already in summer and that simply become visible when the chlorophyll breaks down?

The early autumn nights have been warm this year. But for the birth of an autumn in red colours in tree crowns we need light frost bites at night and sunny autumn days. In places the south sides of maples are eye-catching with beautifully coloured leaves. Whether we will get a fiery autumn the nearest future will show.

… but we see colours everywhere.

Photo Arne Ader

Translation Liis

Rowan tree and cattle

We have lately been spoiled with amazingly beautiful days and star-filled nights. The phenological autumn has started, about ten days before the equinox – with the colouring of leaves on trees, harvesting of grain and flocks of migrating birds.

The autumn colouring of the tree canopy is however very different from year to year. We ask an expert: Why are leaves more red in some years than in others?

Plant physiologist Evi Padu at the University of Tartu: ”The leaves of deciduous trees lose their green colour each autumn and become many-coloured with yellow, red and purple hues. From an aeroplane it is very well visible above the mid-latitude forests how the green foliage recedes slowly as a well defined frontier day by day towards south.

Text and photos  Aare Lindt, www.loodusmuuseum.ee
Translation Liis

Brown-spot pinion

Brown-spot pinion    Täpik-sügisöölane       Agrochola litura

Today the brown-spot pinion occurs all over Estonia but it is not common. Five decades ago the species was still quite rare and then occurred mainly in western Estonia. The moths fly in deciduous and mixed tree stands from the end of August to early October.

Text and photos  Aare Lindt, www.loodusmuuseum.ee
Translation Liis

Founced chestnut

Flounced chestnut     Puna-sügisöölane          Agrochola helvola

The flounced chestnut occurs in the whole of  Estonia and is quite common. It flies in mixed forests and parks and also gardens from the end of August to the end of September, enduring even the first night frosts.

Text and photos Kristel Vilbaste
Translation Liis

Death marked trees

Tuesday morning was a morning like any other. You can still go barefoot across the grass to the mailbox to get a fresh Postimees newspaper to the morning coffee. The cold has still not crept into your marrow on returning from the trip.

But cold bit at my heart when I read the newspaper. The report that told that on the Toomemägi slope at the Pirogov site a felling of trees that are dangerous to people will start today.

Screencap from spring by  Olga, LK forum

Translation Liis

Posted in Estonian by Looduskalender  06.09.2016

The work will take place on  September 9-11.

 At last the  time has come when we can do something in practice for the main actor of this year..

Text and photos  Aare Lindt, www.loodusmuuseum.ee
Translation Liis

Grey chi

Grey chi    Hall-kribuöölane     Antitype chi

The grey chi is a common moth in Estonia. In August and the first half of September they should be seen everywhere but they often remain unnoticed by us thanks to their good camouflage colouring.

Text and photos  Aare Lindt, www.loodusmuuseum.ee
Translation Liis

Sallow

Sallow     Vaarika-kollaöölane     Cirrhia icteritia

The sallow is present in the whole of Estonia and is common everywhere. The first moths hatch in mid-August and their flight lasts until the beginning of October. Meeting them is a sign to us that autumn is approaching.

Science news for the Year of teh Great Tit edited by UT Bird ecology researcher Marko Mägi,marko.magi@ut.ee
Photo Arne Ader
Translation Liis

Despite the fact that it is easier for birds acting together in a group to notice dangers and sound warning calls they too must keep eyes and ears open at foraging to become aware of an approaching threat. Such a mode of foraging is characteristic for many birds feeding in groups. But what happens when warning calls do not reach their aim? For instance in a noisy environment where the efficiency of warning calls is small or one’s mates do not even perceive the calls. Today humans are ever more accompanied by artificial sounds, particularly in cities where traffic noise is several times louder than the natural background of sound. Yet many birds prefer to breed, winter, forage in cities – is then the noise no problem for them?