The big loop trail of Lac d'Anterne and Lac de Pormenaz

Le Dérochoir is the result of successive landslides. The first known and documented dates back to 1471. The second and last, at least for the moment, occurred in 1751. At the foot of the cliff stands a huge landslide cone which forms an unstable slope.
These various landslides created a passage making it possible to cross the Fiz ridge.

Many mountaineers dream of climbing mont Blanc, the highest peak in Western Europe. But it has not always been that popular. In the past, the inhabitants of mountain villages were scared of the mountains environment which led to numerous superstitions, as you can tell from the names given to the summits (“Mont Maudit”, meaning Damned mountain, Aiguilles du Diable, meaning Devil peaks, etc.). Only shepherds, chamois hunters and crystal miners (mining rock crystals) frequented these hostile environments. The first ascents were made by daring "outsiders" who employed these mountain experts as guides.

Everything about this bird is exceptional! With a wingspan up to 2 meters, each couple controls a territory as big as 10 000 football pitches! Its X-ray eyes detect prey movements for over 1 kilometer of distance. Its eyes are like magnifying glasses that magnify 6 to 8 times what its perceives and it has a 240 degrees field of vision. In addition to colors, it is able to detect ultraviolet light, a major asset for this great hunter who can swoop down on its prey at a speed of 350 km/h. But no one is perfect: it misses 9 prey out of 10!

It is the smallest and most discreet of the mountain Galliformes species.
It is much less known than the Black Grouse or the Rock Ptarmigan because it lives exclusively in the forest!
But it is as important as the others from a biological and scientific point of view: it is an indicator species of environmental changes. Its specific demands in terms of vegetation and diversity of tree species ask for an adapted forest management. Bad preservation management of this habitats is one of the main causes of regression of the species.

It is a small tree growing in forest edges. Its fruits are red orange berries loved by thrushes and blackbirds.
The fruits can be used to make to make brandy, jelly or jam. But be aware that they are toxic at maturity, so you have to pick them earlier!
In the nature reserve, the Mountain Ash is part of a participatory science program intended to measure the impact of climate change on the ecosystems of the mountain.

Groundhog is the favorite meal of the Golden Eagle and an important item in a fox diet.
Always vigilant, standing up, it surveys its environment to avoid to be caught. Thanks to a very wide field of vision, and excellent hearing and smell abilities, nothing goes unnoticed. In case of alert, it warns the others with an alarm call: very high-pitched and brief for a danger coming from the sky, whistled and repeated for a danger on the ground. And that danger may be you!

The alpine cabine is a small building which, gattered with others, forms a small hamlet. These constructions were originally intended for the organization of agricultural life in the mountains. These cabins were used in the summer to shelter the shepherds and their family. They were also used for milking and the production of cheese and other dairy products.

These are livestock guardian dogs, their presence is allowed in nature reserves. They defend sheep and ewes from larger predator attacks, such as wolfs. Often large sized dogs, qualified as "molossoid", they spend their lives protecting herds to which they are very attached.

When approaching the herd, it’s very important to observe carefully the dog’s behavior and to take it in account while respecting the following instructions:
- Stay away from the herd (bypass it if possible) - Announce your presence by speaking out loud to avoid surprising the herd and dogs
- Keep calm and avoid sudden movements, keep walking without running. Talk gently to the dogs so that they get used to your presence and accept it.
- Avoid looking straight into the dog’s eyes and hold an object between you and the dog.

The wolf made his return in France, on its own, since the 90’s. Coming from Italy, the species first colonized the southern Alps, then the whole alpine region.

Since the summer of 2019, there is evidence of its presence in some of the nature reserves of Haute-Savoie, which explains the presence of livestock guardian dogs watching over several herds.

Indeed, the wolf is carnivorous. It feeds mainly on wild animals such as Chamois or Roe Deer. But it can also consume ewes or sheep, especially from unprotected herds.

So in order not to interfere with the work of the dogs, please follow the instructions!

This large perennial plant, more than 1m high, is found in meadows, moors or forest clearings of the mountain and subalpine levels.
Used in phytotherapy, it should not be confused with the highly toxic False Helleborine – also called White Hellebore-, next to which it grows and which looks very similar!
Only the flowers are not alike, those of the Gentian are yellow. When not flowering, you can use the leaves to distinguish both species: Gentian is opposite-leaved, while the leaves of the False helleborine borne along the stem alternately (alternate-leaved plant).

This corvid bird, a familiar species of mountain environments, lives mainly in noisy flocks, including sometimes an impressive number of individuals, especially in winter, when snowfall at high altitude forces it to come down to the valley to feed! It is often mistakenly called "Jackdaw", a completely different species of corvid living rather in the plains!
The Chough can be recognized by its black plumage, its lemon yellow beak and its red legs. It’s a fan of aerobatics and there is no doubt that their group movements will amaze you!

In August 1920, a hydroplane left Lausanne, on the shores of Geneva lake, to fly over the Alps. The aircraft, which had just been overhauled, had engine trouble above the Chamonix valley. The pilot noticed the lake of Anterne and estimated that he could land there, which he succeeded. The lake being too small, the plane, even repaired, could not take off again. The engine was removed, and taken down to the valley, and the abandoned hydroplane gradually disintegrated.

These small, shallow bodies of water are mistakenly called lakes.
Locally they are called "laouchets", which means "small bodies of water". Shallow, these bodies of water are home to a rare and protected species, the Sparganium or Narrowleaf Bur-reed, as well as to significant biodiversity. Eventually, these “laouchets” will fill in and become peat bogs.

What you see on the surface of Laouchet is not an algae but a flowering plant with long narrow leaves, like ribbons with changing reflections, that float on the water. The Narrowleaf Bur-reed grows in calm, cold and shallow waters of mountain lakes and ponds. It has, below the surface, stems filled with nutritive reserves called rhizomes. With the natural filling process of Laouchet, the Narrowleaf Bur-reed spreads, intensifying the process by the accumulation of its wilted stems and leaves each winter.

The mountain of Pormenaz is hosting several mines which were exploited from Gallo-Roman times until the 12th century. Argentiferous lead, auriferous and copper pyrites and antimony were extracted from these mines. It was mainly lead and silver that were sought after. About 125 kg of lead and 1 kg of silver were extracted from one ton of ore.

Odonates, more commonly known as dragonflies, are insects.
There are two stages in their lifecycle: a "larva" (or nymph) stage which is aquatic followed by a terrestrial stage, when the adults are grown to adults.
Dragonflies are predators: they are carnivores that feed on different types of prey depending on their stage. They eat other insects as well.
Their distribution is strongly linked to climate conditions and any change has a strong impact on their presence. Destruction of their wetland habitats is one of the main threats to dragonflies.

This amazingly colored lake was probably formed by the landslide of the Dérochoir rock (Fiz ridge to the north) in 1471.
There are several explanations for its emerald green color, including the surrounding vegetation consisting mostly of spruces, which are reflected in its waters. But the presence of blue algae or cyanophyceae in the lake is also a probable cause.
The water comes from sources providing the lake by its surface and underground.

Kissing a toad transforming it into a charming prince is a myth! You must not touch this protected species, which is sensitive to diseases that humans could transmit.
But you can look it in the eyes to observe its horizontal pupil and its orange iris. You will also notice its parotid glands on the back of its head. They are used to secrete a venom, the "bufotoxin" intended to keep away any possible predator.
The toads and frogs are not the same species; toads live mostly in the forest, out of the water, joining it only during the breeding season !

Minnows are very common in highly oxygenated waters. Its presence in high altitude lakes is due to trout fishing activities. Used as bait by fishermen, it colonized these mountain lakes.

The Chub is a rather large fish, very widespread in France. It is an omnivore, which means that it eats everything. In many European countries, especially in the east, it is of highly culinary interest.

In their nest perched against a rock wall, two chicks will soon emerge from their eggs. Only one will survive: the weakest one will be killed by the strongest! In biology, this behavior is called "cainism".
This phenomenon is common for diurnal raptors, since it is part of the species survival strategy: selecting straight away the strongest in order to increase its chances of reaching adulthood. For the parents, it's indeed a great job to feed a voracious juvenile which, from 100g at birth, must reach 5kg by the time it starts flying!

The exhibition an information office Maison de la Réserve naturelle de Passy is located in Plaine-Joux and welcomes you during the school holidays. The permanent exhibition about fauna, flora and landscapes will open the doors to the nature reserve. You may find answers to some of your questions here and can admire the wild species hidden in nature. If the Maison de la Réserve naturelle is closed, don’t worry, go up to the passageway. There is permanent free access to information about former (geological times) and present landscapes, the wonders of biodiversity and the great challenges of the mountains of the future (water, glaciers, global warming...).

The Ibex is not very shy, especially compared to the Chamois sharing its territory.
Unlike most other mountain species, it remains at altitude even when winter and snow arrive.
It then reaches ridges and snow-cleared areas where it will more easily find grass to feed on. This search for food costs a lot of energy. So, if you see it, do not approach and let it leave quietly in order to avoid wasting its precious energy, especially in winter.