10 BIODIVERSITY, OCCURENCE OF ORGANISMS AND THEIR EXTINCTION IS THE RESULT OF EVOLUTION

Animals in each of the four seasons of the year

Autumn

Significant features in the life of animals in autumn are:

• Activities of insects and invertebrates which hide in various places in nature and in people’s homes are on the decrease. There are some exceptions, for example the codling moth is developing and aphids are laying eggs. Ants are gradually gathering in deeper underground parts of anthills where they protect themselves, their larvae and pupae against freezing.

• Beekeepers gradually start insulating the beehives for winter, protecting them from low temperatures in winter.

• Snails look for shelters under leaves and close the opening of their shells with a a calcareous lid. During autumn fish gather on the bottoms of water bodies and streams where they spend the winter in shoals without accepting food. In this season, the fish harvesting from ponds start. Three- and four-year old carps and other types of fish are transferred from ponds to fish farms so that they are ready for the Christmas season.

• In nature amphibians (newts, salamanders, frogs) and reptiles (lizards, snakes) are disappearing. The temperature of their bodies depends on the temperature of their environment. Therefore they must look for shelters in hollows of the stumps, burrows etc. where various species spend the winter collectively. Toads hide away in underground hollows where they burry themselves, for example into the soil, usually as early as the end of September. Frogs hide away a little later; they spend the winter buried in the mud on the bottoms of ponds.

• Flocking and migration of migratory birds. The reason for their migration is, primarily, lack of suitable food in our country. Compass orientation in birds when migrating is still not unequivocally explained. It is assumed that birds use topography, the position of the Sun, stars, geomagnetic field, and inborn instincts for orientation. A part of the birds’ population which live in the proximity of people stay in our conditions in winter. Ornithologists usually ring birds in autumn.

Mammals change their behaviour and their ways of life in autumn. Some species make food reserves and look for shelters. At the end of October the hedgehog builds its shelters with dry grass and leaves under heaps of wood, in heaps of leaves or in various holes where it spends the winter hibernating. The mole digs its corridors deeper in autumn than in summer. In the deeper layers of soil where it does not freeze. It also finds food better there too. Bats spend winter hibernating with their heads hanging down in caves, cellars, lofts etc. Squirrels are very active in autumn. They collect various seeds and fruits which they store in their shelters in roots, in tree hollows etc. Mammals change their hair in autumn. By gradual moulting they get rid of their summer hair and winter coat starts growing. It is thicker and of a lighter colour so that they are protected from frost and they are not too visible on the snow. In autumn wood, from about the middle of September to the beginning of November, a rutting call of the roe deer can be heard.

Winter

Significant features in the life of animals in winter are:

• Absence of mainly invertebrates, amphibians, and reptiles. A variety of birds are missing and some species of mammals are hibernating.

• We find sings of animals’ presence (footprints, remains of food, bite marks, droppings etc.)

• In water, fish usually gather in shoals on the bottom. Common roaches that are fish of cooler waters can be spotted in inshore water. Perches get ready for spring spawning and towards the end of winter they get very ferocious. Burbots even spawn in winter.

• Low temperatures and a lack of food make birds, which stay over winter, come closer to people’s dwellings (tits, common chaffinches, common chaffinches, wood nuthatches etc.). Providing supplemental feed to those birds is our contribution to protection of bird species.

Spring

Significant features in the life of animals in spring are:

• Activities of invertebrates (bees and bumblebees) increase. We can see earthworms in unfrozen soil, snails and slugs under bushes and in grass.

• In water spring fish spawning starts. A female fish lays eggs on suitable places, dips on the bottom, to holes in sand, on the leaves of aquatic plants etc. A male fish fertilizes the eggs with its soft roe. Early in spring pikes spawn. Small pikes feed on plankton and later they attack fries including their own kind.

• Amphibians and reptiles are also active. Frogs search for water where they can reproduce. Female frogs lay eggs in clusters or strings in water. Male frogs fertilize the eggs. The eggs hatch into tadpoles that are dependent on water (they breathe through gills). Lungs and limbs develop gradually and they can live on land. Similarly, newts and salamanders are in their breeding season as well. Lizards and snakes, for example the sand lizard, the viviparous lizard, the slow worm, the grass snake, the Aesculapian snake, the smooth snake, the dice snake and the common European adder leave their shelters.

• Migratory birds return in spring. The first ones to return are larks, later starlings, thrushes etc. At the end of March and at the beginning of April great crested grebes, bitterns, common gallinules, water rails and greylag geese return to water bodies. Between February and April storks return searching for elevated places near people´s dwellings in order to build their nests. At the end of March swallows and little later martins return.

• The young of domesticated birds hatch from eggs (chickens, goslings, ducklings). They are symbols of Easter.

• In spring “winter sleepers” wake up, for example hedgehogs, moles and badgers. All of them look for food in order to replenish their fat reserves. For mammals spring mating is typical, for example in the fields and meadows hares run around at the height of their breeding season which is known as „March madness“. In May a variety of mammals´ young are born (young roe deer, fawns, wild boar piglets). Importantly, the young of domestic animals are born (lambs, kids, calves, foals, piglets, bunnies) which are also symbols of Easter.

• Mammals moult and their hair changes into a thinner coat. They are also coloured more distinctly.

Summer

Significant features in the life of animals in summer are:

• Great activity of insects, colourful butterflies, beetles, bees, wasps, mosquitoes, but acarids as well, for example ticks.

• Activity of amphibians and reptiles (croaking of frogs, reptiles basking in the sunny places).

• Abundant bird singing and their activity

• Mammals guide their growing young.

• Between July and August the roe deer’ rutting season starts, characterized by the males’ special barking voice, known as “bleating”.