White Stork Migration Has Changed
The migration of the white stork ( Ciconia ciconia ) has changed. A few decades ago, once the brood ended, most would fly thousands of miles. Thus it took them a month to cross half of Europe, fly over the Strait of Gibraltar and the Sahara desert.
If they survived this harsh crossing, they reached the areas of sub-Saharan Africa (Mali, Niger, Chad) where they would spend the winter season.
The white stork: the migratory bird par excellence
Not all specimens faced this feat: it was very hard and long, and several birds died during migration.
To avoid crossing the Mediterranean, where the upward warm currents they needed to maintain flight are formed, the storks followed tough migratory routes:
- One over the Bosphorus and the Dardanelles across the Balkans and Turkey.
- Another above the Strait of Gibraltar through the Iberian Peninsula, which is why there are many storks in Spain.
For some decades, however, the migratory habits of these birds have changed. We explain how in the following paragraphs.
The migration of the stork has changed
For several decades now, the migration of the white stork has been different: many specimens, in fact, spend the winter in the nesting places.
This is partly due to the rise in temperatures which causes less severe peninsular winters. Similarly, storks now have food available all year round thanks to the presence of landfills.
As for the Iberian Peninsula, here the storks find a multitude of lagoons and wetlands where they can spend the winter and find food. Some examples are the Tablas de Daimiel national park, in Castile-La Mancha, or the Campillo lagoon in the municipality of Rivas-Vaciamadrid.
The stork’s migration has become shorter
What has been said so far, however, does not mean that storks do not migrate at all. According to a study by SEO / BirdLife, in Spain many storks build their nests in rural areas; when winter comes, they move to cities like Madrid, where they find food in the Valdemingomez landfill, one of the largest in Europe.
This was demonstrated by the application of radio transmitters to a pair of storks, Goyo and Enara, who moved from the Sierra Nevada to the south of Madrid in August .
Everything seems to indicate that this change in the migratory habits of white storks is positive for the survival of the species. Not having to face such a long and dangerous journey, more and more storks survive. Likewise, the continued availability of food is certainly an advantage.
The younger specimens migrate far away
Another aspect that the SEO / BirdLife researchers observed is the difference between adult and juvenile specimens. According to what has been discovered, young people continue to migrate making the dangerous crossing to Africa. The adults, on the other hand, stay in Europe during the winter.
The same study indicates that many birds from other colder European countries choose Spain as their winter location. Thus the quantity of storks in the Iberian country increases substantially: to those that do not reach Africa are added those that come from Northern Europe.
The migration of the white stork: the routes in detail
The Spanish Society of Ornithology, in collaboration with other European bodies, has for years been dedicated to the study of the migration of the white stork.
In fact, they recently presented a detailed study in which, for the first time, data collected by GPS radio transmitters affixed to some migratory storks are included. The results obtained are varied:
- The researchers confirmed the hypothesis that young storks migrate to the Sahel, while adult specimens remain in Spain during the winter.
- Central European storks, many of which spend the winter in Spain, have a higher survival rate (around 50%) than Spanish storks that migrate to Africa. Of the latter, only one in ten returns to the nesting site.
- Most adult specimens spend the winter in Europe. This allows them to survive.
In light of what we have read, we can say that the new migratory habits of the stork are crucial for the species. These changes help us predict the general behavior of many migratory birds.
Although a priori the absence of migration of the white stork appears to have a positive effect in terms of survival, the future repercussions of climate change will need to be assessed.
