A little about Bird Migration

Geese gathering at Alrø bird reserve

The migratory birds move thousands of kilometres each spring and autumn, in spring to the north to their breeding places in Scandinavia in order to nest and have kids. Here is a lot of space and food in summer. In autum the migratory birds fly south to their winter-quarter in the warm countries, where they can rest and find food while snow and frost cover the earth in Scandinavia.

Denmark is a crossroad for both water birds and land birds Birdwatchers estimate that about half a a billion birds pass the southern Scandinavia each autumn.

The land birds prefer to fly over land as far as possible before the flight across sea - therefore they follow the coastline until they are forced to cross the sea.
The water birds prefer to fly across water as far as possible -  therefore they also follow the coast line  until they are forced to fly over land.

An extreme example of bird migration is the Arctic tern which breeds far north near Arctis and overwinters at Antarctis. The species fly usually a yearly migration of ab. 34.000 kilometer. Some individuals can even traverse over 80.000 kilometer yearly, which is the double of the circumference of the earth.

The birds' orientation, the ability to find their way, is genetically determined. How the birds orient themselves is not quite clarified, but it is known that birds use several methods like the Terrestrial magnetic field, constellations, the sun and moon position, polarized light and visual Memory.

Some examinations have shown that the birds not only feed on their fat-reserves but that some of their organs grow smaller during the migration - so the birds exploit the bound energy from fx muscles, stomach, liver and other inner organs. In this way the birds get both energy and a lower weight, which makes the flight easier.

During the migration the birds feed on metabolic water, which is released as a biproduct during the metabolism when the stored fat is burned. The biggest loss of fluid during the flight happens via the exhaled air,  but the birds lose only little fluid through their droppings.

Most of the big birds, like swans and geese, must be taught by their parents in order to find the right migratory route between the winter quarter and the breeding place.

Several migratory birds can fly at least a week in a row without landing.

Some species, like geese and swans, fly in formation during the migration like the V-formation (the wedge formation). A common misunderstanding is that a formation like this has a leading goose in front,  but the birds change place alternately.

It is relatively easy to imagine that a big bird of prey can hover all the way to southern Europe or Africa on spread wings, but it is difficult to imagine a little bird on such a long trip. A bird weighing 10-15 gram has to bring fat in order to be able to survive the tour over long stretches, where it might have no possibility to seek food, water or shadow.

And what I have found here above is just a small part about this fantastic bird migration, the source is wikipedia, the photos; grethe bachmann . 


The bird migration is a wonderful miracle, isn't it? 

The Quill / The Goose Pen

The number of geese in Denmark was in 1800 estimated to ab. 123.00, but in the first livestock-counting in 1888 was registered 213.530 geese. The largest part of geese was driven down through the Jutland peninsula for sale in Sønderjylland and at Funen. The slowly walking geese could at most walk ab. 14-15 km a day and if a geese became too tired, it had to be carried!

The geese were kept for delivering food for the table, but also in order to provide feather and down for pillows and duvets. 200 geese were necessary to deliver feathers and downs for a one bed-clothes. But the feathers were used for other things too, as toothpicks, pipe cleaners and as a paint brush for oil-brushing the breads before baking. The long stiff flight feathers were fine in a duster, and the ribbed feathers could be tied in bundles as scrubbing brush for pots and pans.

The Quill

The large flight feathers were through many centuries used as writing materials. With a special pen-knife the end of the feather was cut off slantwise. The tip was not slit; if the line had to be thicker, then this did not happen by pressing harder, but by giving the feather a turn, so the ink could float out broader.

In several districts the farmers had a duty to deliver suitable goose feathers for the parish school. The school pens were cut by the teacher - but the tip soon lost its elasticity and had to be cut again. The pen feathers were an export article.

The quill was an excellent writing tool. The old documents with their tortuous initials with elegant sweeps show this clearly. The history of the goose-pen can be traced back to the 400s, where they replaced the thin metal-pens in copper or bronze, which were known by the Romans. From the Mediterranean the quill spread across Europe and arrived in the North together with the Latin script and the parchment.

The steel-pen with a slit was invented in the late 1700s, but not mass-produced until ab. 1830. This happened in Birminghan and developed into a good business for the enterprising manufacturer. The feather pen was during a few decades almost out-competed, and in 1880 the production had grown to 15 million steel-pens a week.

In linguistic history we still write with the goose-pen, since the word pen origins from Latin, "penna" meaning feather.

Source: Skalk, archaeological magazine, nr. 5, 1989, V.J.Brøndegaard.


photo: grethe bachmann