On the occasion of the World Migratory Bird Day, which will take place on Saturday, May 14, Katie Zell and I from the League for the Protection of Birds (LPO) are counting these birds that arrive in Alsace for a time or season. ).
Katie Zell is responsible for communication at the LPO, the League for the Protection of Birds, in Alsace. If she is not a migration specialist, she knows enough to sum up these migratory birds. We asked him three questions.
The question may seem silly (feathered), but the answer is quite difficult.
“Birds breed in a place that is suitable for their childhood, for their survival. This place must meet at least three criteria: climatic conditions, environment, rich in food and ecological niche. In fact, birds compete for the most difficult territories. more conducive to reproduction, so for millennia some species have adapted to these empty ecological niches to survive.
When the time changes, food decreases. Birds leave this place in another, more favorable. The environment (for example, for the oriole), the length of the day (swallows, April 15) cause this migration.
Thus, there are two types of migration.
– Premarital migration in the spring (before reproduction). The bird leaves the wintering zone (Africa, Spain, southern France) and joins its breeding area, more or less remote (France, including Alsace, Northern or Eastern Europe). The front of migration is quite wide, even if some axes are well visited (Rhine or Elijah for terns and terns). The first chibionki, Eurasian curls, black kites, white storks, swallows, gray wagtails and larks arrive in Alsace in February-March. In April, the common cuckoo, nightingale, tern, domestic and shore swallows, reeds arrive. Various migrants arrived in May, including a buzzard.
– Postmarital migration (after reproduction) : The bird leaves the nesting place and reaches the wintering place, this is the “autumn migration”, even if for some birds it begins in July (black kite, black swift). Lasts until October-November (blackbirds, finches, melody line (). Migration stops are often longer than in the spring. Migrants can be found almost everywhere, but privileged passages are used during this post-marital journey. In Alsace, the Vosges and Alsatian Jurassic passes are places where post-marital passage is concentrated.
World champion in migration? Polar tern, which breeds in the Arctic and winters in Antarctica.
“It is very difficult to say: there are more than 10,000 species of birds in the world. Some of them are too far to go through Alsace, that’s for sure, but there are so many left! It is difficult to make an inventory of places. We know one thing, there are never absolute rules when it comes to living things. One certainty: Alsace is an important migration corridor. Mission migration regularly counts.
Geographically, Alsace is already well located. In Northern and Western Europe, migration flows usually follow the north-east / south-west axis, and Alsace, located on this trajectory, is one of the transit routes for European migrants. Then Alsace is a real air corridor for the phenomenon suction between the Vosges and the Black Forest is favorable for air flows. Then there is also, above all, drinking water. Of course, the Rhine, as well as Plobsheim, the first major watering place for migrants from the Scandinavian countries.
Different types of migrants can be observed.
– Great travelers wintering in Africa after breeding in Alsace or further north: swallows, black swifts, Eurasian curls, nightingales, hoopoes, European orioles, kite falcons, black kites, red-backed shrike. Water points are also a desirable stop for the migration of waders and other birds that nest in northern Europe.
– Partial migrants the amplitude of movement of which is smaller and part of the populations of which do not carry out migratory movements (sedentary bird): finch, thrush, blackbird, robin, goldfinch, titmouse. Thus, the Vosges passes are particularly intersected by East / West migrations, such as Markstein or Alsatian Jura. Some birds, such as bullfinches, simply flee the harsh winter in the Vosges mountains.
In winter in the Rhine Valley there are a large number of waterfowl (ducks, geese, swans, loons, toadstools) from the northern areas, where food has become inaccessible due to frost. These migrants are “wintering”. They are counted annually in January by Wetlands International.
Over the last decade, there have been between 50,000 and 90,000 waterfowl in the Rhine Valley each winter. These figures are lower than the original estimates, where 100,000 birds were regularly reached in January during the 1970s and 1980s.
“Global warming is disrupting migration, that’s for sure. Winterers are moving less and less away from breeding areas, as temperatures are becoming softer. We see this a lot: a reduction in travel, with the exception of some very programmed ones like swallows, which continue, despite everything, to cross the Sahara or Spain. Storks have adapted. They cover less distance when they don’t just stay put. “
“Light pollution is a very important risk factor. It is also the theme of this World Migratory Bird Day. Anpcen has conducted research on this. Artificial lighting is increasing by at least 2% per year worldwide and is known to adversely affect many bird species. Light pollution poses a serious threat to migratory birds, disorients them during night flights, causes collisions with buildings, disrupts their internal clocks or prevents them from migrating further. There were millions of light-disoriented birds in the United States spinning in a circle and dying of exhaustion.
For example, did you know that a stork born in March goes to the place of wintering itself? Without parents, without a guide? By nature, she knows where she is going, sub-Saharan Africa. And so back. These birds with “innate migration” are oriented at the same time thanks to the stars, due to the magnetic field and certain visual points. We better understand why our artificial light can interfere with them.
So if I had to conclude, I would say: take care of migratory birds, they are precious. Do not destroy their nest, do not shoot game. They have traveled thousands of miles to come to us, they are exhausted, they have withstood the storm, escaped from the clutches of their predators, greet them. A cup of water, seeds… so that they find at least their habitat.