The osprey has not yet returned from its stay in Africa, where it spends the winter, but in Fontenay-le-Vicomte (Essonne), we are busy welcoming it.
At the request of the departmental council, a wooden platform 10 meters high, on which a nest is perched, has just been installed on an islet in the marshes of the town by means of a helicopter.
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Since 2005, a pair of this protected species (listed in Annex I of the EU Birds Directive) has settled from late March to August in this part of Essonne to breed there.
Two nests were built by this bird of prey with an average wingspan of 1.5o meters: one in the Misery marsh, located straddling the towns of Echarcon and Vert-le-Petit, the other a few kilometers away. from there, in the marshes of Fontenay-le-Vicomte.
Only 90 couples identified in France
But a few months ago, it was destroyed.
The pine tree on which it rested, threatening to give way, was cut down.
“He had become too dangerous.
We could not take the risk that it would fall when the little ones were inside, explains Julien Daubignard, in charge of forestry and European heritage for the department.
No other tree met the criteria for them.
They need to settle very high in order to protect themselves from predators, for example crows that eat eggs.
It also needs a wide field of vision.
"
The nest, perched on a platform 10 meters high, was installed by helicopter in Fontenay-le-Vicomte (Essonne).
LP / Nolwenn Cosson
To date, 90 couples have been identified in France.
Thirty of them nest on the cliffs in Corsica.
The others settle in the forest of Orleans.
Except one, which returns every year to Essonne, seduced by the tranquility of the two marshes and the many fish to taste.
It is therefore impossible not to find an alternative to the destroyed nest.
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The imposing wooden structure was set up by the company Smae (Société service material aménagement pour l'environnement), in its premises located in Bondoufle.
Then transported by helicopter because the area is inaccessible on foot.
"The other possibility would have been to build it directly on site, but it would have been complicated to bring all the equipment on site, and the island is really small", specifies one of the managers of the company.
In fifteen years, 17 babies were born on site
At the top of the platform, a few tree branches have been put down.
The rest of the work will be done by the ospreys.
In fifteen years, 17 young were born in one of the two nests.
“The male almost always arrives first.
His female, generally always the same, joined him shortly after, details Julien Daubignard.
One of the babies born in 2009 has returned every year since 2014. He first mated with his mother
(Editor's note: there is no risk of inbreeding for this species)
.
For two years, he has had a new female.
Last year they had three cubs.
"
In a few weeks, all eyes will be on the arrival of the couple.
“So far, only one of the two nests has been occupied,” explains Sylvain Larzillière, a specialist bander at the Center for Research on the Biology of Bird Populations.
But last year, other ospreys flew over the site for several days.
We hope that this year, two couples will settle here.
"
